D Z h All h

MEDICATION CARE UNIT

Dr Zahra AllamehClinical Pharmacist

Imam Hossein children hospital

دارويي خطاهاي گزارش فرم

پزشكي دارويي خطاهايبا� كه است اين مبحث اين ارائه از هدف

بيماران� دارودرماني در محتمل خطاهاي انواع بهتر شناختخطاها� ايجاد كننده مستعد عوامل شناختخطا� ايجاد از ي شگ پ هاي اه شناخت خطا� ايجاد از پيشگيري هاي راه شناخت

بخشيد� بهبود را بيمار ايمني توان .مي

مطالب سرفصلهايخطا� اپيدميولوژيخطا� انواعكننده� مستعد عواملپيشگيري� هاي راه

Epidemiology

� More people in USA die in a given year as a result ofmedical errors than from motor vehicle accidents, breastcancers, or AIDS

� Majority are medication errorsMajority are medication errors

� Indian study of paediatric intensive care unitreported 68.5% of all errors were medication errors

5

Medication Errors

� Most medication errors do not result in patient harm� potential error/ near miss/ actual error/ harm

� S di ti lt i t t hi h� Some medication errors result in catastrophic harm ordeath

Classifying medication errors

A circumstances exist for potential errors to occur

B an error occurred but did not reach the patient

C error reached the patient but did not cause harm

D patient monitoring required to determine lack of harm

NCC MERP. accessed Jan 2012. www.nccmerp.org

E error caused temporary harm and some intervention

F temporary harm with initial or prolonged hospitalization

G error resulted in permanent patient harm

H error required intervention to sustain the patient’s life

I error contributed to the patient’s death

Types of medication errors� Medication Administration

� Environment light� Wrong time error (after 60 min)� Omission error (in 24 hour)� Errors in dilutionErrors in dilution� inhalers

� Monitoring and Reporting of Medication Effects on thePatient� Compliance

اپيدميولوژيشود� مي بيمار آسيب به منجر كه نيست خطايي آن تنها دارويي .خطايهمكاران� و فرضي مطالعه طي80در در كه كردند عنوان پرستاران درصد

اند داشته دارويي خطاي گذشته .ماهسال� به95در رسيد92اين .درصدن� نشا ا ا خطا ا ا ا ش ا گ ل نميدهد� نشان را دارويي خطاي ميزان اين ها گزارش .ولي

خطاها� دهي گزارش سيستم در نقصاسم� بدونشدن� مواخذه از ترس بدون

High risk with High Alert Drugs — highly toxic drugs or drugswith a narrow therapeutic range have a high risk of causing

devastating injury or death

High risk with High Alert Drugs — highly toxic drugs or drugswith a narrow therapeutic range have a high risk of causing

devastating injury or death

باال هشدار با داروهايدارو دوز و وزن است/نوشتن ضروري كيلوگرم

تلفظ و شكل نظر از مشابه )نوشتاري(داروهاي

� Most medication errorsoccur during physicianordering (39%)

� and medicationadministration (38%)administration (38%)

B- According to category�Most frequently reported types of medication errors:-

15

Dosing Errors in Children

� Current research shows that, in pediatrics, dosing errors are the mostcommon type of medication error due to:

� Lack of standard doses for many drugs (often off label) used in children

� Individual doses based on age, weight or body surface area requirel l ti th t t f il ( i id l tti )

16

calculations that are prone to failure (even in ideal settings)� Tenfold errors are common dosing errors, and are often associated with

higher toxicity than other types of dosing errors� Failure to correctly estimate a child’s weight continues to be a common

problem

CASE: Jose Martinez was a 2-month-old who exhibited early signsof CHF. His physician ordered IV Digoxin over an extendedlength of stay. However, due to a decimal point error, Josereceived a dose that was 10 times what was intended. Jose died.

Medication Errors in the ED

A recent study involving medication administration in a simulatedpediatric emergency scenario revealed numerous opportunities

for nursing performance improvement:

a. Communication – 45% orders were not verbally repeated back

17

b. Converting Dose –14.2% converted incorrectly (convert mg into ml)

c. Selecting medication – 7.3% wrong vials selected

d. Dilution & reconstitution – 40% Ceftriaxone not properly constituted

e. Measuring Dose – 32.7% measured doses ≠ to intended dose

Medication errors� The Joint Commission's sentinel event database

includes more than 350 medication errorsresulting in death or major injury.

Medication Errors� Of those, 63 percent related, at least in part, to

breakdowns in communication, andapproximately half of those would have beenavoided through effective medicationgreconciliation.

Medication Errors� Medication reconciliation is intended to be a

systematic process designed to enhance patientsafety by validating at every point of care apatient’s current medication regimen.p g

دارويي تلفيق فرم

Risk factors for prescribing errors

Work environment

Workload

Communication within the team

Physical and mental well beingPhysical and mental well being

Lack of knowledge

Organizational factors such asinadequate training

Low perceived importance ofprescribing

An absence of self awareness of errors

What is the nature of prescribingerrors?� Incorrect or irrational drug choices� Ineffective prescribing� Underprescribing� OverprescribingOverprescribing

What is the nature of prescribingerrors?� Knowledge-based errors� Rule-based errors� Action-based errors (slips)� Memory base errors (lapses)� Transcribing and other writing errors

� Transcribing andVerifying of Physician Orders� Handwriting (English or Persian)� Telephone orders ( sound alike drugs- inamrinon and

amiodaron)

� Dispensing and Delivering MedicationsDispensing and Delivering Medications� Look alike and sound alike drugs (capital letters) (similar

packaging report) niFEdipine and niCARdipine� Mathematical error

Approaches for reducing prescribingerrors

� Electronic prescribing� Computerized physician order entry systems

Role of prescribers� knowledge of generic names & brand names of available

drugs in their local setting

� Specify dosage form, drug strength & complete directionson prescriptions

� Using both brand name & generic name on prescription

� Purpose of medication

� Legible handrwiting

28

Types of medication errors� The medication use process has five stages, and each of them could be considered as

“Error Prone”…� Physician Ordering

� Prescription error (interval, dose, dosage form)� failure to consider patient’s age; renal or hepatic function� Inaccurate medication history taking (medication reconciliation)• Inappropriate use of decimal points ( 2 mcg / 1 0 mcg)• Inappropriate use of decimal points. (.2 mcg / 1.0 mcg)• “u,” “U,” or “IU” for units

• Micro gram µ• Use of abbreviations (e.g. AZT has led to confusion between zidovudine and

azathioprine).

� Using package units like “one tablet” instead of specific milligram dosage� Writing ambiguous or incomplete orders� Write route of administration on all orders

� Write out directions completely (e.g., “daily” not “QD” or “OD”)29

10 Strategies for MinimizingDispensing Errors� 1. Ensure correct entry of the prescription.� 2. Confirm that the prescription is correct and

complete.� Whenever in question, it is important to call the prescriber to

clarify any uncertainties or doubts regarding the prescription.� 3. Beware of look-alike, soundalike drugs.� 4. Be careful with zeros and abbreviations.� 5. Organize the workplace.� 6. Reduce distraction when possible.� 7. Focus on reducing stress and balancing heavy

workloads.

� 8.Take the time to store drugs properly.� 9.Thoroughly check all prescriptions.� 10. Always provide thorough patient counseling

� Approximately 83% of errors are discovered during counselingand are corrected before the patient leaves the pharmacyand are corrected before the patient leaves the pharmacy.

The Joint CommissionOfficial “Do Not Use” List1Applies to all orders and all medication-related documentation that

is handwritten (including free-text computer entry) or on pre-printed forms.

Do Not UseU (unit)( )

Potential ProblemMistaken for “0” (zero), the number “4” (four) or “cc”Write "unit“

Use InsteadWrite "unit"

The Joint CommissionOfficial “Do Not Use” List1Do Not UseIU (International Unit)Potential ProblemMistaken for IV (intravenous) or the number 10 (ten)Use InsteadWrite "International Unit"

The Joint CommissionOfficial “Do Not Use” List1Do Not UseQ.D., QD, q.d., qd (daily) Q.O.D., QOD, q.o.d, qod (every

other day)Potential ProblemMi k f h h P i d f h Q i k f "I" dMistaken for each other Period after the Q mistaken for "I" and

the "O" mistaken for "I"Use InsteadWrite "daily"Write "every other day"

The Joint CommissionOfficial “Do Not Use” List1Do Not UseTrailing zero (X.0 mg)* Lack of leading zero (.X mg)*Exception:A “trailing zero” may be used only where required to

demonstrate the level of precision of the value being reported,such as for laboratory results, imaging studies that report size ofy g g plesions, or catheter/tube sizes. It may not be used in medicationorders or other medication-related documentation.

Potential ProblemDecimal point is missedUse InsteadWrite X mgWrite 0.X mg

The Joint CommissionOfficial “Do Not Use” List1Do Not UseMS - MSO4 and MgSO4Potential ProblemCan mean morphine sulfate or magnesium sulfate Confused for

hone anotherUse InsteadWrite "morphine sulfate"Write "magnesium sulfate"

Additional Abbreviations, Acronyms and Symbols (Forpossible future inclusion in the Official “Do Not Use” List)

Do Not Use> (greater than) < (less than)Potential ProblemMisinterpreted as the number “7” (seven) or the letter “L”

C f d f hConfused for one anotherUse InsteadWrite “greater than”Write “less than”

Additional Abbreviations, Acronyms and Symbols (Forpossible future inclusion in the Official “Do Not Use” List)Do Not UseApothecary unitsPotential ProblemUnfamiliar to many practitioners Confused with metric unitsUse InsteadUse metric units

Additional Abbreviations, Acronyms and Symbols (Forpossible future inclusion in the Official “Do Not Use” List)

Do Not Use@

Potential ProblemMistaken for the number “2” (two)Use InsteadWrite “at”

Additional Abbreviations, Acronyms and Symbols (Forpossible future inclusion in the Official “Do Not Use” List)

Do Not UseccPotential ProblemMistaken for U (units) when poorly writtenUse InsteadWrite “mL” or "ml" or “milliliters” (“mL” is preferred)

The Joint CommissionOfficial “Do Not Use” List1Do Not UseµgPotential ProblemMistaken for mg (milligrams) resulting in one thousand-fold

doverdoseUse InsteadWrite "mcg" or “micrograms”

The Joint CommissionOfficial “Do Not Use” List1Do Not Use“HS” (at bedtime)Potential ProblemUse Instead(at bedtime)

ISMP List of Error-Prone Abbreviations,Symbols, and Dose Designations� AD, AS, AU� Right ear, left ear, each ear� Mistaken as OD, OS, OU (right eye, left eye, each eye)� Use "right ear," "left ear," or "each ear"

ISMP List of Error-Prone Abbreviations,Symbols, and Dose Designations� OD, OS, OU� Right eye, left eye, each eye� Mistaken as AD,AS, AU (right ear, left ear, each ear)� Use "right eye," "left eye," or "each eye"

ISMP List of Error-Prone Abbreviations,Symbols, and Dose Designations� BT� Bedtime� Mistaken as "BID" (twice daily)� Use "bedtime"

ISMP List of Error-Prone Abbreviations,Symbols, and Dose Designations� D/C� Discharge or discontinue� Premature discontinuation of medications if D/C (intended

to mean "discharge") has been misinterpreted as"discontinued" when followed by a list of dischargediscontinued when followed by a list of dischargemedications

� Use "discharge" and "discontinue"

ISMP List of Error-Prone Abbreviations,Symbols, and Dose Designations� IJ� Injection� Mistaken as "IV" or "intrajugular“� Use "injection"

ISMP List of Error-Prone Abbreviations,Symbols, and Dose Designations� IN� Intranasal� Mistaken as "IM" or "IV“� Use "intranasal" or "NAS"

ISMP List of Error-Prone Abbreviations,Symbols, and Dose Designations� HS� Half-strength� Mistaken as bedtime� Use "half-strength" or "bedtime“� hs� At bedtime, hours of sleep� Mistaken as half-strength

ISMP List of Error-Prone Abbreviations,Symbols, and Dose Designations� o.d. or OD� Once daily� Mistaken as "right eye" (OD-oculus dexter), leading to oral

liquid medications administered in the eyeU "d il "� Use "daily"

ISMP List of Error-Prone Abbreviations,Symbols, and Dose Designations� Per os� By mouth, orally� The "os" can be mistaken as "left eye" (OS-oculus sinister)� Use "PO," "by mouth," or "orally"

ISMP List of Error-Prone Abbreviations,Symbols, and Dose Designations� q.d. or QD**Every day� Mistaken as q.i.d., especially if the period after the "q" or the

tail of the "q" is misunderstood as an "i“� Use "daily"

ISMP List of Error-Prone Abbreviations,Symbols, and Dose Designations� Qhs� At bedtime� Mistaken as "qhr" or every hour� Use "at bedtime"

ISMP List of Error-Prone Abbreviations,Symbols, and Dose Designations� Qn� Nightly� Mistaken as "qh" (every hour)� Use "nightly"

ISMP List of Error-Prone Abbreviations,Symbols, and Dose Designations� q6PM, etc.� Every evening at 6 PM� Mistaken as every 6 hours� Use "6 PM nightly" or "6 PM daily"

ISMP List of Error-Prone Abbreviations,Symbols, and Dose Designations� SC, SQ, sub q� Subcutaneous� SC mistaken as SL (sublingual); SQ mistaken as "5 every;"

the "q" in "sub q" has been mistaken as "every" (e.g., aheparin dose ordered "sub q 2 hours before surgery"heparin dose ordered sub q 2 hours before surgerymisunderstood as every 2 hours before surgery)

� Use "subcut" or "subcutaneously"

ISMP List of Error-Prone Abbreviations,Symbols, and Dose Designations� Ss� Sliding scale (insulin) or ½ (apothecary)� Mistaken as "55“� Spell out "sliding scale;" use "one-half" or "½"

ISMP List of Error-Prone Abbreviations,Symbols, and Dose Designations� i/d� One daily� Mistaken as "tid“� Use "1 daily"

ISMP List of Error-Prone Abbreviations,Symbols, and Dose Designations� TIW or tiw� 3 times a week� Mistaken as "3 times a day" or "twice in a week“� Use "3 times weekly"

ISMP List of Error-Prone Abbreviations,Symbols, and Dose Designations� Drug name and dose run together (especially problematic for

drug names that end in "L" such as Inderal40 mg;Tegretol300 mg)Inderal 40 mgTegretol 300 mgMistaken asInderal 140 mg

� Mistaken asTegretol 1300 mgMistaken asTegretol 1300 mg� Place adequate space between the drug name, dose, and unit

of measure

ISMP List of Error-Prone Abbreviations,Symbols, and Dose Designations� Numerical dose and unit of measure run together (e.g.,

10mg, 100mL)10 mg 100 mL� The "m" is sometimes mistaken as a zero or two zeros,

risking a 10- to 100-fold overdose� Place adequate space between the dose and unit of measure� Place adequate space between the dose and unit of measure

ISMP List of Error-Prone Abbreviations,Symbols, and Dose Designations� Abbreviations such as mg. or mL. with a period following the

abbreviation� mg mL� The period is unnecessary and could be mistaken as the

number 1 if written poorlynumber 1 if written poorly� Use mg, mL, etc. without a terminal period

ISMP List of Error-Prone Abbreviations,Symbols, and Dose Designations� Large doses without properly placed commas (e.g., 100000

units; 1000000 units)� 100,000 units 1,000,000 units� 100000 has been mistaken as 10,000 or 1,000,000; 1000000

has been mistaken as 100 000has been mistaken as 100,000� Use commas for dosing units at or above 1,000, or use words

such as 100 "thousand" or 1 "million" to improve readability

ISMP List of Error-Prone Abbreviations,Symbols, and Dose Designations

ISMP List of Error-Prone Abbreviations,Symbols, and Dose Designations

بندي بسته و ظاهري شكل مشابهت گزارش

66

در داروشكلشباھت

���� ������ �����

����������������������������� �� �� �!"#$%�%�

&�� '�$

(�) '�$

73

Can you read this???

Neither can we!!!

Approaches to reducing dispensingerrors include

� Ensuring a safe dispensing procedure.� Separating drugs with a similar name or

appearance.� Keeping interruptions in the medicine

d d dadministration procedure to a minimum andmaintaining the workload of the nurse at a safeand manageable level.

� Awareness of high risk drugs such as potassiumchloride and cytotoxic agents.

� Introducing safe systematic procedures fordispensing medicines in the pharmacy.

Role of Pharmacist� Refer back to doctor if any confusion

� Basic knowledge of dosing regimens for commonly used drugs

� Computer reminder for serious confusing name pairs to avoidp g perrors in prescription

� Stickers of ‘Alert’ in areas where LASA drugs stored

� In case of wrong prescription, pharmacist should not react infront of patient

76

CONTRIBUTING FACTORS TO DRUGADMINISTRATION ERRORS

Failure to checkthe patient’sidentity prior toadministration

Environmentalfactors such anoise,interruptions,poor lighting

Wrong calculationto determine thecorrect dose

APPROACHES TO REDUCE DRUGADMINISTRATION ERRORS INCLUDE:� Checking the patient’s identity.� Ensuring that dosage calculations are checked independently by

another health care professional before the drug is administered.� Ensuring that the prescription, drug, and patient are in the same

place in order that they may be checked against one another.place in order that they may be checked against one another.� Ensuring the medication is given at the correct time.� Minimizing interruptions during drug rounds� Double check high alert medications� Ask unfamiliar orders

� Be sure to read labels at least 3 times, beforeduring after administration of the drug.

� Prepare the medicine in a well lighted room.� Check the expiry date of the drug before

administration

APPROACHES TO REDUCE DRUGADMINISTRATION ERRORS INCLUDE:

administration.� Be aware about ambiguous orders or drug names

and numerical and Consult doctor if any doubt.� Be alert to usually large dosage or excessive

increase in dosage ordered.� When in doubt, check order with prescriber,

pharmacist, literature ..

B- According to category� Types of reported medication errors that most frequently caused

harm:-

80

� Patient should confirm name & strength of prescribed drugsbefore leaving doctor’s office

� Educated about the storage conditions of drugs (e.g. Insulin)

Role of patient

� Keeping medicines away from reach of children also shouldbe emphasized

� Patient should carry all previous prescriptions to avoidrepeating the drug or notice any change in prescriptions

81

Conclusion

We care about HOW? Not WHO?and there is big difference.

82

Preventing Medication Errors (1)

� Establish consensus group of physicians, nurses, andpharmacists to select best practices

� Introduce a punishment-free system to collect andrecord information about medication-related errors

� Develop written procedures with guidelines andchecklists for IV fluids and high-risk medicines (e.g.,insulin, heparin, narcotics)

Five High 5s priority risk areas� 1. Managing concentrated injectable medicines

(concentrated injectables).� 2.Assuring medication accuracy at transitions of care

(medication reconciliation).� 3. Performance of the correct procedure at the correct

body sites (correct site surgery).� 4. Communication during patient care handovers.� 5. Improved hand hygiene to prevent health care

associated infections.

ايمني9 حل راهدارويي� خطاي از جلوگيري جهت مشابه تلفظ و نام با داروهاي به توجهخطا� از جلوگيري جهت بيمار فردي مشخصات به توجهبيمار� تحويل زمان در موثر ارتباطبيمار� بدن صحيح محل در صحيح پروسيجر انجامالكتروليت� هاي محلول غلظت الكتروليتكنترل هاي محلول غلظت كنترلخدمات� ارايه انتقالي مراحل در درماني دارو صحت از اطمينانها� لوله و سوند نادرست ازاتصاالت اجتنابتزريقات� وسايل از يكباره صرفا استفادههاي� مراقبت با مرتبط عفونت از جلوگيري براي دست بهداشت بهبود

سالمتي

مثالها�Orderكودك براي الزيكس داروي اشتباه بجاي3دوز ،5/1mgماهه

شده15 داده دستور ميليكردن� وارد هنگام سفترياكسون داروي افتادن قلم بهorderاز پرونده از

كاردكساشتباه� بيمار به اپركس داروي تزريقجايگزين� سرم سي10اشتباه سي1بجايkclسي سيامينواسيد� داروي دوز ثبت در جاي200اشتباه به سي سي20سي سيكاردكس� به پرونده از الزيكس داروي دوز انتقال در گرم50:اشتباه ميلي

جاي گرم5به ميليدستور4گرفتن� كردن وارد عدم دليل به سفترياكسون اضافه DCدوز

پزشك

87

Wow, that is a lot of todo’s and not to do’s…butultimately keeping kidssafe is our goal!

BASIC MATHEMATICS USED INPHARMACY PRACTICE

•Fractions•Decimals•Ratios and Proportions

COMMON CALCULATIONS IN THEPHARMACY

•Converting Quantities between the Metric and CommonMeasure Systems

•Calculations of Doses•Preparation of Solutions

Système International PrefixesPrefix Meaningmicro- one millionth (basic unit × 10–6, or unit × 0.000,001)milli- one thousandth (basic unit × 10–3, or unit × 0.001)centi- one hundredth (basic unit × 10–2, or unit × 0.01)deci- one tenth (basic unit × 10–1, or unit × 0.1)hecto- one hundred times (basic unit × 102, or unit × 100)kilo- one thousand times (basic unit × 103, or unit × 1000)

Common Metric Units: WeightBasic Unit Equivalent

1 gram (g) 1000 milligrams (mg)

1 milligram (mg)1000 micrograms (mcg),

one thousandth of a gram (g)

1 kilogram (kg) 1000 grams (g)

Basic Unit Equivalent

1 meter (m) 100 centimeters (cm)

Common Metric Units: Length

1 centimeter (cm)0.01 m

10 millimeters (mm)

1 millimeter (mm)

0.001 m

1000 micrometers

or microns (mcm)

Basic Unit Equivalent

1 liter (L) 1000 milliliters (mL)

Common Metric Units: VolumeTable 5.2

1 milliliter (mL)0.001 L

1000 microliters (mcL)

Measurement and Calculation Issues

It is extremely important that decimals

Safety Note!

It is extremely important that decimalsbe written properly. An error of asingle decimal place is an error by afactor of 10.

Conversion Instruction Examplekilograms (kg) tograms (g)

multiply by 1000 (move decimal point three places to the right) 6.25 kg = 6250 g

Common Metric Conversions

Table 5.3

grams (g) tomilligrams (mg)

multiply by 1000 (move decimal point three places to the right) 3.56 g = 3560 mg

milligrams (mg) tograms (g)

multiply by 0.001 (move decimal point three places to the left) 120 mg = 0.120 g

Conversion Instruction Exampleliters (L) tomilliliters (mL)

multiply by 1000 (move decimal point three places to the right)

2.5 L = 2500 mL

Common Metric Conversions

Table 5.3

right)

milliliters (mL) toliters (L)

multiply by 0.001 (move decimal point three places to the left)

238 mL = 0.238 L

�0.125 mg ? Mcg

�0.008 g ? mcg

�0.5 g ? Mg

�225mg ? g

Measurement Unit Equivalent within System Metric Equivalent

1 tsp (teaspoonful) 5 mL

1 tbsp (tablespoonful) 3 tsp 15 mL

1 fl oz (fluid ounce) 2 tbsp 30 mL (29.57 mL)*

1 cup 8 fl oz 240 mL

Household Measure: Volume

* In reality, 1 fl oz (household measure) contains less than 30 mL; however, 30 mL is usually used. When packaging a pint, companies will typically present 473 mL, rather than the full 480 mL, thus

saving money over time.

1 cup 8 fl oz 240 mL

1 pt (pint) 2 cups 480 mL*

1 qt (quart) 2 pt 960 mL

1 gal (gallon) 4 qt 3840 mL

1 drop 15 gtt 1 ml

Measurement Unit Equivalent within System Metric Equivalent

1 oz (ounce) 30 g1 lb (pound) 16 oz 454 g

Household Measure: Weight

1 lb (pound) 16 oz 454 g2.2 lb 1 kg

Measurement and Calculation Issues

New safety guidelines are discouraging use

Safety Note!

New safety guidelines are discouraging use

of Roman numerals.

Roman Arabic Roman Arabic

ss 0.5 or 1/2 L or l 50

I or i or i 1 C or c 100

Comparison of Roman and Arabic Numerals

I or i or i 1 C or c 100

V or v 5 D or d 500

X or x 10 M or m 1000

Terms to Remember

• metric system• meter• meter• gram• liter

Fractions

• When something is divided into parts, each part is considered a fraction of the whole.

Fractions

If we have a 1000 mg tablet, • ½ tablet = 500 mg• ¼ tablet = 250 mg• ¼ tablet = 250 mg

fraction

Terminology

a portion of a whole that is represented as a ratio

Numerical Ratios

Ratios represent the relationship between • two parts of the whole • one part to the whole• one part to the whole

Numerical Ratios

Written with as follows:

1:2 “1 part to 2 parts” ½ 1:2 “1 part to 2 parts” ½ 3:4 “3 parts to 4 parts” ¾

Can use “per,” “in,” or “of,” instead of “to”

Terminology

ratioa numerical representation of therelationship between two parts of thewhole or between one part and thewhole

Numerical Ratios in the Pharmacy

1:100 concentration of a drug means . . .

Numerical Ratios in the Pharmacy

1:100 concentration of a drug means . . .. . . there is 1 part drug in 100 parts solution. . . there is 1 part drug in 100 parts solution

Proportions

• An expression of equality between two ratios.

• Noted by :: or =• Noted by :: or =

3:4 = 15:20 or 3:4 :: 15:20

Terminology

proportionan expression of equality between two ratios

Proportions

If a proportion is true . . .product of means = product of extremes

3:4 = 15:203:4 = 15:203 × 20 = 4 × 1560 = 60

Proportions in the Pharmacy

• Proportions are frequently used tocalculate drug doses in the pharmacy.

• Use the ratio-proportion method any time• Use the ratio-proportion method any timeone ratio is complete and the other ismissing a component.

Terminology

ratio-proportion method

a conversion method based on comparing a complete ratio to a ratio with a missing component

method

Example 3 Solve for x.

Example 3 Solve for x.

Percents

• Percent means “per 100” or hundredths.• Represented by symbol %

30% = 30 parts in total of 100 parts,

30:100, 0.30, or

10030

Terminology

percentthe number of parts per 100; can be written as a fraction, a decimal, or a ratio

Percents in the Pharmacy

A 1% solution contains . . .

• 1 g of drug per 100 mL of fluid• 1 g of drug per 100 mL of fluid• Expressed as 1:100, 1/100, or 0.01

Percents in the Pharmacy

A 1% hydrocortisone cream contains . . .

• 1 g of hydrocortisone per 100 g of cream• 1 g of hydrocortisone per 100 g of cream• Expressed as 1:100, 1/100, or 0.01

Safety Note!

The higher the percentage of a dissolved substance, the greater the strength.

Percents in the Pharmacy

• Multiply the first number in the ratio (the solute) while keeping the second number unchanged, you increase the strength.unchanged, you increase the strength.

• Divide the first number in the ration while keeping the second number unchanged, you decrease the strength.

Equivalent Values

Percent Fraction Decimal Ratio

45% 0.45 45:1004545% 0.45 45:100

0.5% 0.005 0.5:100

100

1005.0

Converting a Ratio to a Percent

1. Designate the first number of the ratio as the numerator and the second number as the denominator.the denominator.

2. Multiply the fraction by 100%, and simply as needed.

Converting a Ratio to a Percent

5:1 = 5/1 × 100% = 5 × 100% = 500%

1:5 = 1/5 × 100% = 100%/5 = 20%1:5 = 1/5 × 100% = 100%/5 = 20%

1:2 = 1/2 × 100% = 100%/2 = 50%

Converting a Percent to a Ratio

2% = 2 ÷ 100 = 2/100 = 1/50 = 1:5010% = 10 ÷ 100 = 10/100 = 1/10 = 1:1075% = 75 ÷ 100 = 75/100 = 3/4 = 3:475% = 75 ÷ 100 = 75/100 = 3/4 = 3:4

Percent to Decimal4% = 0.04 4 ÷ 100% = 0.0415% = 0.15 15 ÷ 100% = 0.15200% = 2 200 ÷ 100% = 2

Decimal to Percent0.25 = 25% 0.25 × 100% = 25%1.35 = 135% 1.35 × 100% = 135%0.015 = 1.5% 0.015 × 100% = 1.5%

Basic Mathematics cont. (Problem Set #1)

�Convert the following fractions to decimal numbers:

a. 1/2b. 3/4c. 1d. 2/5

e. 1/3f. 5/8g. 50/100h. 12/48 e. 1/3f. 5/8g. 50/100h. 12/48

i. 11/2j. 2 2/3k. 5 1/4l. 3 4/5

Basic Mathematics cont. (Problem Set #1)

�Answers for problem set #1:

a. 0.5b. 0.75c. 1d. 0.4

e. 0.33f. 0.625g. 0.5h. 0.25 e. 0.33f. 0.625g. 0.5h. 0.25

i. 5.5j. 2.67k. 5.25l. 3.8

Proportional Calculations

a xb c

�solving for x by multiplying (a)(c) and dividing by (b)solving for x by multiplying (a)(c) and dividing by (b)

�write out the units for (a), (b), and (c)

Ratio and Proportions

If potassium chloride (KCl) elixir contains 20milliequivalents(mEq) of potassium (K+) ion in eachmilliliter, how many milliliters will be needed to provide130 milliequivalents of K+ ion.

Answer:If there are 20 mEq in 1 mL, 130 mEq will be in how manymLs?Simply, 130/20 =6.5 mLs

Ratios and Proportions cont.�A vial of drug contains 40mg/2ml. How many milliliters (ml) are

required to obtain 300mg of drug?

mg300= mg40. 1mg)300ml)(2mg)(X)= (40. (22mlX

mg)300ml)(2(. X = 3ml15. X=4(40mg)

5. TIP – Make sure your units cancel

Ratio and Proportion

Example 1.You have a 10-ml vial of aminophylline labeled "25 mg perml". How many milliliters must be injected to administerdose of 125 mg?

25 mg 125 mg-------- = -----------1 ml X ml

25mg (X) = (1 ml) (125 mg)X = 5 ml

Percentage expressionPercentage expression is a unique concentration term used in pharmacy that signifies the number of parts of solute per 100 parts of total solution.

There are four different percent expressions:

Percent weight by volume(%w/v): refers to the number of g of solution 100 mL of solution.

e.g.1%(w/v)is 1g in 100 mL

Percent volume by volume (%v/v):refers to the number of mL of liquid in 100 mL of solution.solution.

e.g. Alcohol, U.S.P. is 95 % (v/v). This means that it has 95 mL of pure alcohol (100%) per every100 mL of solution.

Percent weight by weight (%w/w):refers to the number of g of solute in 100 g of mixture. e.g. Nitro‐Bid®2% (w/w)ointment contains 2g of nitroglycerine per 100 g of ointment.

Milligram percent (mg%):refers to the number of mg per 100 mL of solution.

e.g. A solution containing 2.5 mg % has 2.5 mg per100 mL

Percentage Preparations

Example 1. How much Potassium Chloride in grams isneeded to prepare a 1 Liter solution of 3% KCl solution?

Answer: 3% = 3 grams / 100mls1 Liter = 1000 mlsNext: 3 grams X grams

---------- = -----------100 mls 1000 mls

Finally: x = 30 grams

MOLARITY and OSMOLARITY

�The concentration of a solute in a solution isexpressed as its “Molarity”. It tells you how much ofa solute is present. The units of molarity are “moles”(mols).

�Osmolarity is a concept that allows you to determine�Osmolarity is a concept that allows you to determineif water will move from one side of a membrane tothe other side. That is: will “Osmosis” occur? Theunits of osmolarity are “osmols” (osm). Water willalways move across a membrane into the solutionwith the higher osmolarity.

�In order to determine a solutions’ osmolarity youwill first need to figure out its molarity.

To calculate molarity one needs to understand the followingideas.1.That 1 Gram-Molecular Weight of a compound is itsmolecular wt. expressed in grams and that

1 Gm.-Mol. Wt. = 1 mole. i.e., 1 mole of glucose = 180grams.

2.You will need to know the Mol. Wt. of the solute, the volumeof the solution, and how much solute (in grams) is present inthat volume of solution.3. 1 mole of anything contains 6.02 x 1023 particles of that3. 1 mole of anything contains 6.02 x 1023 particles of that

solute. (Avogadro’s Law)

4. 1 mole of solute per liter of solution = a 1 molar solution = 1M.

5. To calculate the molarity of a solution, use the followingequation:

Amount of solute (in grams) per literM = -----------------------------------------------------M = -----------------------------------------------------

Mol. Wt. of solute

6. To calculate the osmolarity of a solution use the followingequation:

OSM = M x the number of particles of dissociation.

� calculate the osmolarity of D5W (5% dextrose in water).

� 1 mole of glucose = 180 grams.

� 5 % solution has 50 grams of solute dissolved in one liter.

� 278 mOsmol/L

� Normal saline 0.9% ?

Dilution, Concentration and Alligation� There are occasions in which the dilution or concentration of a pharmaceutical

preparation is either desirable or required.

� 1st quantity X 1st concentration = 2nd quantity X 2nd concentration

� Q1 X C1 = Q2 X C2

� Example(1): if 500 ml of 15% v/v solution are diluted to 1500 ml, what will be the percentage strength (v/v)

� Q1 X C1 = Q2 X C2� Q1 X C1 = Q2 X C2

� 500(ml) X 15(%) = 1500(ml) X x(%) X = 5%

� Example(2): if 50 ml of 1: 20 w/v solution are diluted to 1000 ml, what is the ratio strength (w/v)?

� 1 : 20 = 5%

� Q1 X C1 = Q2 X C2

� 50(ml) X 5(%) = 1000(ml) X x(%) X = 0.25% = 1: 400

١٤٤

� The pharmacist hands you a 1.5L bottle of a 20% solution and asks that you mix it with sterile water to make as much 12% solution as possible. How much sterile water will you use ?

A. 525mLA. 525mL

B. 800mL

C. 1000mL

D. 1250mL

براي تعيين ميزان داروي تجويزي از درصد موجود از فرمول ذيل استفاده مي �:شود

غلظت موجود * حجم برداشته شده = غلظت درخواستي *حجم درخواستي �

�

اما موجودي داروخانه . مورد نياز باشد% 7.5سديم بيكربنات 5mlاگر : مثال �:باشد % 8.4سديم بيكربنات

حجم برداشته شده * �8.4 حجم برداشته شده 5 * 7.5 = = 4.5 ml

�4.5 ml برداشته و با آب مقطر قابل تزريق به % 8.4از سديم بيكربنات.مي رسانيم 5mlحجم

Dilution, Concentration and AlligationStock solutions: are concentrated solutions of active (e.g. drug) or inactive (e.g. colorant)

substances and are used by pharmacists as a convenience to prepare solutions of lesserconcentrations.

Example(1): How many milliliters of a 1:400 w/v stock solution should be used to make 4liters of a 1 : 2000 w/v solution?

1:400 = 0.25% and 1: 2000 = 0.05% and 4 liters = 4000 ml

Q1 X C1 = Q2 X C2

4000(ml) X 0.05(%) = X (ml) X 0.25(%) X = 800 ml

Example(2): How many milliliters of a 1:50 stock solution of phenylephrine hydrochlorideshould be used in compounding the following prescription.

R/ phenylephrine HCl 0.25%

Rose water ad 30 ml

Sig. For the nose

1 : 50 = 2 %

x X 2% = 30 X 0.25% X = 3.75 ml

١٤٧

Dilution, Concentration and Alligation� Some calculations used in pharmacy in which the strength of a diluted portion of a

solution is defined, but the strength of the concentrated stock solution used to prepare it must be determined.

� e.g. when the pharmacist need to prepare and dispense a concentrated solution and direct the patient to use small volume (5 ml, teaspoonful) and dilute it in a specified volume of water.

� Example(1): How many milliliters of water should be added to 300 ml of a 1:750 w/v solution of benzalkonium chloride to make a 1:2500 w/v solution? solution of benzalkonium chloride to make a 1:2500 w/v solution?

� 1 750

� X 300 X = 0.4 g

� 1 2500

� 0.4 X X = 1000 ml 1000 – 300 = 700 ml

١٤٨

Dilution, Concentration and AlligationDilution of alcohol: when water and alcohol are mixed there is a physical contraction in

the resultant volume.

Example: How much water should be mixed with 5000 ml 85% v/v alcohol to make 50% v/v alcohol?

Q1 X C1 = Q2 X C2

5000(ml) X 85(%) = X (ml) X 50(%) X = 8500 ml

so enough water is added to make 8500 ml.

Dilution of acids: the strength of concentrated acids (official) are expressed as % w/w, Dilution of acids: the strength of concentrated acids (official) are expressed as % w/w, while diluted acids are expressed as w/v. Consider the specific gravity of conc. Acids in calculations

Example: How many mls of 37% w/w HCl having a specific gravity of 1.20 are required to make 1000 ml of dil HCl 10% w/v?

1000 X 0.1 = 100 gm of HCl 100% in 1000 ml of 10% w/v

Q1 X C1 = Q2 X C2

100g X 100(%) = X (ml) X 37(%) X = 270 g of 37% acid

270/1.2 = 225 ml١٤٩

Dilution, Concentration and Alligation

Dilution and concentration of solids and semisolids:Example: How many grams of opium containing 15 w/w of morphine and how many

grams of lactose should be used to prepare 150 g of opium containing 10% w/w ofmorphine?

Q1 X C1 = Q2 X C2

X g X 15(%) = 150g X 10(%) X = 100 g of 15% opium

150 g - 100g = 50 g of lactose150 g - 100g = 50 g of lactose

Example: How many grams of 20% benzocaine ointment and how many grams ofointment base (diluent) should be used in preparing 5 lb. of 2.5 % benzocaine ointment?

5 lb = 454 g X 5 = 2270 g

Q1 X C1 = Q2 X C2

2270g X 2.5(%) = X g X 20(%) X = 283.75 or 284 g

2270 – 284 = 1986 g of ointment base١٥٠

Determining Milliequivalents of Compounds

To determine the number of milliequivalents of a compound: (1) identify the formula of the compound

(2) separate the formula into atoms (3) determine the moleclular weight of the compound

multiply the weight of each atom by the number of those atoms �multiply the weight of each atom by the number of those atoms�add the products together, the sum is the molecular weight

mEq = molecular weight (expressed in milligrams)

valence

Valences and Atomic Weights of Common Elements

Element Valence Atomic Weight RoundedValue

hydrogen (H) 1 1.008 g 1 gcarbon (C) 4,2 12.011 g 12 gnitrogen (N) 5,3 14.007 g 14 g

For pharmaceutical calculations, atomic weights are usually rounded to the nearest tenth (i.e., one unit to the right of the decimal point).

nitrogen (N) 5,3 14.007 g 14 goxygen (O) 2 15.999 g 16 gsodium (Na) 1 22.9898 g 23 gsulphur (S) 6,4,2 32.064 g 32.1 gchlorine (Cl) 7,5,3,1 35.453 g 35.5 gpotassium (K) 1 39.102 g 39.1 gcalcium (Ca) 2 40.08 g 40.1 g

گرم به واالن اكي تبديل�

)گرم(مولكولي وزن= واالن اكي يك�

ظرفيت

:كاربردي و شايع امالح ظرفيت�

2 :منيزيم سولفات 1 : بيكربنات سديم 1 :سديم كلرور 1 :پتاسيم كلرور� 2 :منيزيم سولفات 1 : بيكربنات سديم 1 :سديم كلرور 1 :پتاسيم كلرور

دارد؟ واالن اكي ميلي چند آن سي سي 1 باشد مي %15 موجود KCL اينكه به توجه با :مثال�)K=39، CL=35.5(

KCL واالن اكي يك = 39 + 35/5 = گرم �5.74

meq چون و� mg و ، است واالن اكي يك = 1000 74500 = Meq ميلي يك پس ، بود خواهد 1000

KCL واالن اكي = mg سي يك هر پس دارد KCL گرم ميلي 150 آن سي سي يك يعني % 15 طرفي از.بود خواهد 74/5 .باشد مي KCL واالن اكي ميلي 2 حاوي آن سي

پمپ انفوزيون سرنگ

را دارو مقدار همان كنيد، حل دارو ميكروست روش در آنچه اساس بر اگر دستور حسب بر دقيقه در قطره تعداد كنيد حل سي سي 100 سرنگ در

: مثال ، بود خواهد ساعت در سي سي مقدار همان ، پزشك شده داده

µ دستور بيماري اگر g /min 10سرم TNG دستور بيماري اگر روش همانند اگر دارد µ g /min 10سرم TNG روش همانند اگر دارد چون بريزيد سرنگ سي سي 100 در TNG گرم ميلي 5 شما ميكروستي

در سي سي 12 همان پس شود مي دقيقه در قطره 12 ميكروستي روش در استفاده سي سي 50 سرنگ اگر فقط بود خواهد سرنگي روش در ساعت . گردد نصف بايد مقدار اين كرديد حل آن در را دارو مقدار همان و كرديد

محاسبه و تبديل درصدهاي دارويي به گرم

در موجود داروي مقدار ( ها سرم و داروها از زيادي تعداد اينكه به توجه با گلوكز ، ليدوكائين ، كلسيم ( است شده نوشته )%( درصد صورت به آنها ظروف

آن بتواند بايد شده داده دستور داروي مقدار رساندن براي پرستار ) هيپرتونيك.كند برداشت فوق ظرف از و محاسبه را مقدار

سي سي در گرم = % درصد

% 1 كائين ليدو محلول : مثال

mg 1000 = 1 سي سي 100 گرم

X )سي سي 1 )مجهول

Common sense and estimation

The golden rule: have some idea of what a sensible answer should be. develop estimation skillscheck any calculation by working it backwards or using a check any calculation by working it backwards or using a different method.It is not safe to assume that the prescription is correct and another check should be based on the recommended dose range in the paediatric formulary in local use

Recommended Volume for Administration Per Sites:

� Intradermal = 0.1 ml (example PPD, allergy testing)� Subcutaneous injection = 0.5-1.0 ml per site� Intramuscular injection = 3.0 ml per site

(1 ml in the deltoid)(1 ml in the deltoid)� IV injection (IV push) = 1-60 ml

Mental arithmetic and easy calculations

� There are two common ways of calculating using mental arithmetic. Look at the following example:

� A child is prescribed 5mg of a drug that is available in liquid form as 2mg per ml.liquid form as 2mg per ml.

� Estimate first – do you need more or less than the available dosage?

Example

� Method 1� Look for relationships between the numbers involved.� You may recognize that 5 is 2 ½ times 2. � So, if there are 2mg in 1ml, there will be� 5mg in 2 1/2 x 1ml.� Required amount = 2.5ml.� Method 2� If you know what volume of the liquid contains 1mg of the drug, then you

can multiply it by 5 to calculate the volume containing 5mg. � 2mg per ml indicates that 1mg would be found in ½ ml or

0.5ml. � If 1mg = 0·5ml, then 5mg = 0.5 x 5 = 2.5.� Required amount is 2.5ml

Using a calculator

� use a calculator for the more complex arithmetic required for some of the computations within this guide.

Formula

• What you want x what it’s in / what you’ve got

� WIG

Example

� Prescription states 200mg (milligrams)� You have an ampoule of 500mg (milligrams) in 4ml (millilitre� What volume contains the dose you need?

Answer

�200mg x 4ml / 500mg = 1.6ml

Converting units

� All weights, volumes and times in any equation must be in the same units. With weights the unit changes every thousand. For example, you need 1000 micrograms (mcg) to make 1 milligram (mg) and 1000 milligrams to make one gram (g)(mg) and 1000 milligrams to make one gram (g)

گرم 1000يك كيلوگرم برابر با - �1ميلي گرم 1000يك گرم برابر با - �2ميكروگرم 1000يك ميلي گرم برابر با - �3

:واحد اندازه گيري معمول حجم و تبديالت آنها عبارتند از

: واحد اندازه گيري معمول وزن و تبديالت آنها عبارتند از

:واحد اندازه گيري معمول حجم و تبديالت آنها عبارتند از سيسي 1000يك ليتر برابر است با - �1ليتر مايع برابر است با يك كيلوگرميك - �2

:فاكتور قطرهست سرم يا ماكرودراپقطره 15يك سي سي برابر است با �يا ميكرودراپ ميكروست قطره 60يك سي سي برابر است با �

WITHIN SYSTEMS

�MEMORIZE:

�1 gram (g or G) = 1000 milligrams (mg)�1 liter (l or L) = 1000 milliliters (ml or mL)�3 teaspoons (t) = 1 tablespoon (T)�1 cubic centimeter (cc) = 1 milliliter (ml)

BETWEEN SYSTEMS

�MEMORIZE:�1 gram (G, GM, gm) = 15 grains (gr)�60 milligrams (mg) = 1 grain (gr)

1 tablespoon (T) = 15 ml �1 tablespoon (T) = 15 ml�1 kilogram (kg) = 2.2 pounds (lb)�1 ounce (oz) = 30 ml or 30 cc�1 cc = 15 drops (gtt)�1 inch (in) = 2.5 centimeters (cm)

�1. 685 micrograms (mcg) = ? mg �2. 24 ml = ? litres �3. 1500g = ? kg �4. 4.5 litres = ? ml �4. 4.5 litres = ? ml �5. 0.02mg = ? mcg �6. 7mg = ? mcg �7. 0.4kg = ? g �8. 8 grams = ? mcg �Tricky questions: 9. 200mg/4ml = ? mg/ml �10. 280mg/7ml = ? mcg/ml

Type B calculations

� These are infusion rate calculations.

� For example:

Prescription states 30 mg/hour• Prescription states 30 mg/hour

• You have a bag containing 250mg in 50ml

� At what rate (ml/hr) do you set the pump?

Dose (mg/hr) x volume in syringe (ml) / Amount in syringe (mg) = Infusion rate

� 30 x 50 / 250 = 6ml� 30 x 50 / 250 = 6ml� Therefore the calculation shows that, to give 30mg per

hour, the infusion pump rate would need to be set at 6ml per hour.

Type C calculations

� Infusion rate is required, but dose is ‘mg per kg’.

� For example:

Prescription states 0.5mg/kg/hour• Prescription states 0.5mg/kg/hour

• You have a bag of 250mg in 50ml

• Your patient weighs 5kg

� At what rate (ml/hr) do you set the pump?

� To do this calculation you still use the WIG equation as above, but with one extra step to work out the ‘what you want’.

� First you need to convert the mg per kg into total mg by multiplying it by the patient’s weight.multiplying it by the patient’s weight.

� So for a person who weighs 5kg, 0.5mg per kg is the same as 2.5mg. Once you have calculated this, the infusion rate can be worked out as in the Type B calculations.

� In this instance:

� 0.5mg/kg/hr x 5kg x 50ml / 250mg = 0.5ml/hr

Type D calculations

� Infusion rate required, but dose is in mg/kg/min.

� For example:

Prescription states 0.5mg/kg/min• Prescription states 0.5mg/kg/min

• You have a syringe of 250mg in 50ml

• Your patient weighs 5kg

� At what rate (ml/hr) do you set the pump?

� As before, you will need to calculate what you want by multiplying the amount per kg by the patient’s weight. In this case:

� 0.5mg x 5kg = 2.5mg

� This time, however, the prescription states the rate per minute. The pump demands that the rate be set in ml per hour, therefore the rate pump demands that the rate be set in ml per hour, therefore the rate per minute will need to be converted before the equation can be completed, by multiplying 2.5 by 60; that is, 2.5mg/min (35 milligrams per minute) is converted to 150mg/hr (150 milligrams per hour).

� From here, once again we use the type B calculation to find the infusion rate, which as shown will be 420ml/hr.

� 150 x 50 / 250mg = 30ml/hr

Type E calculations

� Infusion rate is required, but the dose is in mcg/kg/min.

For example:� Prescription states 3 micrograms (mcg)/kg/min� Prescription states 3 micrograms (mcg)/kg/min� You have a syringe of 100mg in 50ml� Your patient weighs 5kg� At what rate do you set the pump (ml/hr)?

�As before, what you want is calculated by multiplying the amount per kg by the patient’s weight, that is:

�3mcg/kg for a 5kg person is 15mcg

�Next the prescription rate needs to be converted into rate per hour, that is,

�15mcg/min = 900mcg/hr

�The prescription is in micrograms, but in your syringe you have milligrams. Both need to be in the same units, so you must convert one to the other, in this case

mcg to mg. 900mcg/hr is the same as 0.9mg/hr.

�The calculation is then as follows:

�0.9 x 50 / 100 = 0.45ml/hr

Common variations:

one millionth one thousandth Basic units:

one thousand times

Prefix/symbol: micro (µ) milli (m) kilo (k)

Weight: microgram (µg or mcg or microgram)

It is impossible to show a microgram!

milligram (mg)

A pinch of salt weighs approximately 1 milligram

gram (g)

A paperclip weighs approximately 1 gram

kilogram (kg)

1 kilogram of flour

Volume: microlitre (µL) millilitre (ml) litre (L)

A syringe can measure microlitres.

The drip from a tap is approximately 1 millilitre.

1 litre of milk

Length/height: micrometre

Bacteria can be measured in micrometres.

millimetre (mm)

A CD is approximately 1 millimetre deep (120 mm across)

metre (m)

A large adult stride is approximately 1 metre.

kilometre (km)

Roads are measured in kilometres.

: دستور داروييروزانه mg 200شربت سديم والپروات�mg 200= سي سي 5هر �

محاسبه دوزاژ داروهاي خوراكي

: دستور داروييروزانه mg250شربت آموكسي سيلين �mg 125= سي سي 5هر �

نوشته )%( درصد صورت به آنها ظروف در موجود داروي مقدار ( ها سرم و داروها از زيادي تعداد اينكه به توجه با� داده دستور داروي مقدار رساندن براي پرستار (منيزيوم و هيپرتونيك گلوكز ،ليدوكائين كلسيم، مثل )است شده:كند برداشت فوق داروهاي از و محاسبه را مقدار آن بتواند بايد شده

از سي سي 100 در گرم حسب بر دارو مقدار يعني شود مي مطرح دارو يك براي درصد عنوان وقتي�: محلول

محاسبه دوزاژ داروهاي درصدي

: محلولسي سي ١٠٠در گرم = (%) درصد

درصد١محلول ليدو كائين : مثال �)ميلی گرم ١٠٠٠( گرم١سی سی در ١٠٠X= ١٠ mg در سي سي ١

ميلي گرم ليدوكايين وريدي 60: دستور دارويي�%2ويال ليدوكايين : فرم دارويي موجود�

سي سي 100گرم در �2

:مثال

سي سي 100گرم در �2يا

سي سي 100در گرم ميلي 2000سي سي 100ميلي گرم در �2000

X=سيسي 3 ميلي گرم 60سي سي 3= ميلي گرم �60

گرم 1آمپول كلسيم : دستور دارويي�)سي سي 10(درصد 10كلسيم : فرم دارويي موجود�

10gr 100cc

:مثال

1gr X= 10cc

.مهم نمي باشد) آمپول يا ويال( در محلول هايي كه به صورت درصد مي باشند حجم وشكل دارو : نكته

گذاشتن و )%(درصد عالمت حذف با فقط باشد، شده مشخص درصد با دارويي غلظت گاه هر� ميلي واحد به آمده بدست عدد اين حاوي دارو آن سي سي يك ، دارو آن عدد جلوي صفر رقم.باشد مي گرم

:مثال

:روش ساده تر

:مثال

:(تجويز مي شوند) L/hيا ml/h(براي سرم هايي كه بر اساس ميلي ليتر و يا ليتر بر ساعت �):1فرمول

محاسبه تعداد قطرات در دقيقه براي ميكروست�

محاسبه تعداد قطرات ست سرم و ميكروست حاوي دارو

: تعداد قطرات در دقيقه براي سرم محاسبه �

v)(مقدار سرم بر حسب سي سي= تعداد قطرات در دقيقه (t)زمان بر حسب ساعت

v)(مقدار سرم بر حسب سي سي= تعداد قطرات در دقيقه t(4(زمان بر حسب ساعت

*مقدار داروي دستور داده شده× مقدار محلول بر حسب سي سي× 60تعدادقطرات= ---- ------------------------------------------------------

*مقدار كل داروي موجود

باشند ,meq/min, eq /min , µ/min ,mg/minبراي كليه دوزهايي كه بر حسب) 2فرمول (:يعني همگي بر اساس دقيقه باشند فرمول به شكل زير مي باشد

meq ,µواحدهاي دوز دارو و مقدار دارو در فرمول بايستي يكسان باشند مثال هر دو بر حسب : نكته,mg, eq باشند...و.

.ضرب مي شود kgاگر دوز تجويزي بر حسب وزن بيمار باشد عدد حاصله از فرمول در وزن بيمار بر حسب

µاگر� /kg/minاينكه به توجه با باشد، شده تجويز كيلوگرمي 60 بيمار براي دوپامين١٠

؟است چند قطرات تعداد شود، حل ميكروست سي سي100 در دوپامينmg٢٠٠ آمپول يك

۶١٠٠×٠×)۶١٠×٠ ( gtt/min قطرات تعداد = ـــــــــــــــــــــــــــــــــــــــــــــــــــ = ١٨

:مثال

gtt/min قطرات تعداد = ـــــــــــــــــــــــــــــــــــــــــــــــــــ = ١٨ ٢٠٠٠٠٠

ساعت 1دوز دارو بر حسب × محلول بر حسب سي سيمقدار تعدادقطرات= ------------------------------------------------------

مقدار دارو در محلول

واحد در ساعت تجويز شده است تعداد قطره در دقيقه را محاسبه كنيد 1000براي بيمار هپارين با دوز : مثال�

باشند ,meq/h ,µ/h ,mg/h, eq /hبراي كليه دوزهايي كه بر حسب)3فرمول (: يعني همگي بر اساس ساعت باشند فرمول به شكل زير مي باشد

واحد در ساعت تجويز شده است تعداد قطره در دقيقه را محاسبه كنيد 1000براي بيمار هپارين با دوز : مثال�

١٠٠٠× ١٠٠ gtt/min تعداد قطرات= ــــــــــــــــــــــــــــــــــــــــــ= ٢٠ ۵٠٠٠

براي ميكروست همان ) قطره در دقيقه(در كليه محاسبات عدد به دست آمده �)پمپ انفوزيون( سي سي در ساعت مي باشد

ml/hدر واقع عدد تنظيم شونده روي همه دستگاه هاي انفوزيون بر حسب � ml/hدر واقع عدد تنظيم شونده روي همه دستگاه هاي انفوزيون بر حسب �.مي باشد) بر حسب ميكروست( است كه همان قطره در دقيقه

در انفوزيون هايي كه مدت زمان زيادي طول مي كشد به مدت زمان : نكته�.پايداري دارو در سرم دقت كنيد

Microset

����������min �×����� ���� ℎ������×�۶٠�

�������� ������������ � . باشد microgram/kg/minقطره ميكروست در دقيقه وقتي تجويز بر اساس=

����������ℎ ��� �×����� ���� ℎ���� ��×� �

بر اساس اوردر پزشك داروھا روش محاسبه قطره ميكروست

�������� ������������ �

����������

ℎ ��� �×����� ���� ℎ���� ��×�۶٠��������� ����������

�� .باشد microgram/kg/hourوقتي تجويز بر اساسقطره ميكروست در ساعت =�

���������min �×����� ���� ℎ������×�۶٠�

�������� ����� .باشد milligram/kg/minوقتي تجويز بر اساسقطره ميكروست در دقيقه = �

���������ℎ��� �×����� ���� ℎ������×�۶٠�

�������� ����� .باشد milligram/kg/hourوقتي تجويز بر اساسقطره ميكروست درساعت = �

�

:اگر شما يعني

:SRFفرمول

سي سي 100هرگاه هر دارويي با هر ميزاني در قطره آن حاوي همان 6ميكروست ريخته شود

مقدار داروست كه ريخته شده با يك واحد كوچكتر

� mg ۵TNGكرديد حل ميكروست سي سي100 در،

.داردµ ۵TNG آن قطره 6 ��mg 200كرديد حل ميكروست سي سي100 در دوپامين،.دارد دوپامين ميكروگرم µ٢٠٠ آن قطره 6 ��mg۵كرديد حل ميكروست سي سي100 در دارويي از ٠،.دارد ميكروگرم µ۵٠ آن قطره 6 �

تعيين ميزان داروي تجويزي از درصد موجود از فرمول ذيل استفاده مي براي �:شود

غلظت موجود ×حجم برداشته شده = درخواستي غلظت × حجم درخواستي

c1v1 = c2v2

:محاسبه ساخت محلول ها

c1v1 = c2v2اما موجودي داروخانه . مورد نياز باشد% 7.5بيكربنات سديم ml 5اگر: مثال

:باشد % 8.4سديم بيكربنات ml4.5= 8.4× حجم برداشته شده= 7.5× 5 برداشته شده حجمml 4.5 حجم برداشته و با آب مقطر قابل تزريق به % 8.4سديم بيكربنات ازml 5

.مي رسانيم

�BODY WEIGHTFLUID PER DAY

:حجم مايع نگهدارنده به روش زير محاسبه مي شود

FLUIDPERDAY BODYWEIGHT

100 mL kg/0–10 kg

1,000 mL + 50 mL kg foreachkg>/ 10 kg

11–20 kg

1,500 mL + 20 mL kg foreachkg>/ 20 kg

>20 kg

Serum DW5% 1580cc+15.8ccKCl 15%+15.8cc NaCl 20% ساعت ٢۴در عرض

كيلويي 24مايع نگهدارنده براي كودك : مثال

Heparin Drip Calculation

�Your patient has a DVT is ordered for a heparin infusion to start at 18 units/kg/hour per the practitioner’s order. His weight is 75kg. The heparin infusion comes in a 500ml bag with 25,000

units. Calculate the starting rate of the infusion (ml/hour).units. Calculate the starting rate of the infusion (ml/hour).

Heparin Infusion Rate: Total Units (in IV bag) = Units/hour Total Volume (ml) X (ml/hour)

�Step 1: Calculate the starting units per hour.

�18 units X 75 kg = 1350 units/hour

�Step 2: Calculate the starting rate of the Infusion (solve for X). �Heparin Infusion Rate: 25,000 units = 1350 units/hour 500ml X

(ml/hour) 25,000 units (X ml/hr) = 675,000 X ml/hr = 675,000 25,000 X = 27 ml/hour 675,000 25,000 X = 27 ml/hour

meq/kg 3-2ميزان سديم مورد نياز روزانه • meq/kg 2-1ميزان پتاسيم مورد نياز روزانه •

و يا به يك روش ديگر3 يا30meq/Litحدودا را نگهدارنده مايع سديم ميزان• meq/100 cc .بدهيم سديم هم77meq/Litتا بزرگتر دركودكان بويژه هستيم مجاز البته.دهيم مي

:نگهدارندهالكتروليت مايع

.بدهيم سديم هم77meq/Litتا بزرگتر دركودكان بويژه هستيم مجاز البته.دهيم مي2 يا 20meq/Lit حدوداً نگهدارنده مايع پتاسيم ميزان• meq/100 ccدهيم مي.

20meq/Lit KCL:

30meq/Lit :Nacl

30meq/Lit :NaHco3

.كنيم مي استفاده20 % محلول از نياز مورد سديم تامين براي

% محلول از سي سي 1 دهيم مي بيمار به كه سرم سي سي 100 هر ازاي به كار، سهولت براي

20NaCl20 . كنيم مي اضافهNaClكنيم مي اضافه .

باشد مي پتاسيم 2meqحاوي آن سي سي1 هر كه 15KcL % محلول از پتاسيم تامين براي

اين از سي سي 1 بيمار سرم از cc100هر ازاي به است كافي منظور بدين .كنيم مي استفاده

.برسيمmeq/Lit20هدف به تا كنيم اضافه را محلول

20meq/Litو بيکربنات 20meq/Litبيمار با out putجايگزينی پتاسيم

١٠٠: حجم کل ادرار �

:مثال

Vomiting: 3-5cc/kg/ time

Diarrhea:5-10 cc/kg/time

AOL( Abnormal ongoing loss)

V(A2-A) v1=A2-A1

10(5-3) v1=

%3سي سي سالين 10براي ساختن

10(5-3) v1=5-0.9

V1= 5از نرمال سالين

Question # 1

� How many milliliters per kilogram per day is the neonate receiving, if the neonate is receiving D10W at 7.25 ml/hr for 24 hours and Fat Emulsion 20% solution at 4.5 ml/hr for 20 hours. Neonate weighs 4.7 lbs. Neonate weighs 4.7 lbs.

�

� ml/kg/day�

ml/kg/day�

Question # 2

�The infant, who weighs 2,375 grams, is getting 150 mg/ kg/ day of Ampicillin in 4 equal doses, How many milligrams per dose

should be given? ��

�

�mg/dose�

�

�

mg/dose wt. 2375 grams �

Question # 3

�The infant, who weighs 2,855 grams, will receive how many micrograms per kilogram per minute when the Dopamine is

infusing at 750 mcg/kg/hr

�mcg/kg/min �

mcg/kg/min wt. 2855gm

�

Question # 4

�The neonate, who weighs 3 lbs 10 oz, will receive how many milligrams per minute of Dopamine when the infant is getting

950 mg/kg/hr.

�mg/min�

mg/min�

Question # 5

�The baby, who weighs 1,667 grams, has an IV of Dopamine 35 milligrams in 100 milliliters and is getting 12.5 mcg/kg/minute.

What will the nurse set the IV infusion rate at to delivery 12.5 mcg/kg/min?mcg/kg/min?

�ml/hr

ml/hr wt. 1667 gm.�

Question # 6

�The neonate weighs 1,922 grams. The physician has ordered Gentamycin 2 mg per kilogram per dose stat and then every 18 hours for 7 days.

�A. What is the total number of doses the neonate will receive in 7 days?��

�total number of doses in 7 days�

�

�

�

�B. How many total milligrams will the neonate receive in 7 days?�mg in 7 days.

A. total number of doses in 7 daysDoses /TT

�

B. mg in 7 days=TT.�

Question # 7

�The physician has ordered Dexamethasone 0.65 mg/kg/day with a dose to be given every 6 hours. The infant weighs 3

lbs. 8 oz. �A. How many milligrams per dose will the infant receive? �A. How many milligrams per dose will the infant receive?

�mg/dose�B.How many milligrams will the infant receive in 24

hours?�mg/24 hrs

�

B. mg/24 hrs

�

�1) How many 40mg tablets of codeine are required for a dose of 0.08g?

�2) Gentamycin dose is 7mg/kg daily given in divided doses three times. How much should a patient weighing 84kg three times. How much should a patient weighing 84kg

receive at each dose?

�3) A 70mg post immunisation dose of paracetamol is required. Stock available is 140mg in 5ml. What volume is required?

�4) A 40mg dose of Amoxicillin is required. Stock available is 200mg in 10ml. What volume is required?

�5) Using an infusion pump what rate is required, in ml/hr, for 1 litre of 0.9% sodium chloride over 4 hours?

�6) Using an infusion pump what rate is required, in ml/hr, for 3 litre of 0.9% sodium chloride over 6 hours?

�7) 800ml of sodium chloride 0.9% is to run over 8 hours. Calculate the drip rate in drops per minute. The I.V. set administers 20

drops/ml. �8) A unit of blood with a volume of 380ml is to run over 4 hours.

Calculate the drip rate. The I.V. set administers 15 drops/ml.

�9) 1.8 litres of drug x is to run over 9 hours. Calculate the drip rate in drops per minute. The I.V. set administers 12 drops/ml.

�10) 900ml of drug y is to run over 3 hours. Calculate the drip rate in drops per minute. The I.V. set administers 10 drops/ml.

THE END

وزارت بھداشت درمان و آموزش . راھنمای جامع اعتبار بخشی ملی بيمارستان ھای ايران١٣٩۵پزشکی

th 19: Harriet Lane Handbook: A Manual for Pediatric House OfficersMegan m.(Nineteenth) Edition byTschudy

Eugenia M. Fulcher,, MEd, EdD, RN, CMA (AAMA) and Margaret Schell Frazier, RN, CMA, BS. Introduction to Intravenous Therapy for Health Professionals: ISBN: 9781416033998