RahmatiniBagian Farmakologi & Terapi

Fakultas Kedokteran Universitas Andalas

FARMAKOLOGI KLINIK

WHO ( 1988) Disiplin dalam bidang kedokteran berdasarkan

prinsip ilmiah, menyatukan keahlian farmakologi &

keahlian klinik dengan tujuan meningkatkan manfaat &

keamanan obat

FARMAKOLOGI KLINIK

Terapi Efektif, Aman , Rasional

TUJUAN

RATIONAL DRUG USE

Benefit – Risk - Cost

F.Kinetika F Dinamika F Ekonomi

Ratio

PHARMACOLOGICAL ASPECTS IN CLINICAL PRACTICE

PharmacodynamicPharmacokinetic

How drugs actThe dynamics of drug conc. in

the body

* Absorption / bioavailability

* Distribution

* Biotransformation

* Excretion

Kelemahan bekal pengetahuan selama pre-service and in service

Aktivitas promosi yang berlebihan Rasa tidak aman (insecurity) krn ketidak

pastian diagnostik Rasa gengsi up date Sistim suplai obat yang tidak baik Beban pelayanan yang terlalu berat Kurangnya buku pedoman pengobatan Tekanan dan permintaan pasien, dll….

Pemakaian antibiotika untuk ISPA non bakteri

Pemakaian multivitamin untuk indikasi yang tidak jelas

Pemakaian steroid utk terapi simtomatik berbagai kondisi

Pemakaian injeksi tanpa indikasi yang jelas

Pemakaian antibiotika profilaksis utk semua tindakan bedah , dll….

THERAPEUTIC DRUG MONITORING (TDM)

Measuring the plasma drug conc.

Provide useful information about the adequacy of the dosage

regimen or the likehood toxicity

Therapeutic Drug Monitoring (TDM)

Ph kinetic Ph dynamic

Drug-interaction

• Therapeutic response• Side effects• Toxic effects

• Measuring/ interpreting

plasma drug conc.

Dru

g co

nc. (

mg /

l)

Time (hour)

10

20

30

40

1 2 3 4

Therapeutic level

Low therapy

Drug toxicity

Time-drug conc. relationship

m.e.c

1. Narrow margin of safety drugs

2. Drugs for prevention/ therapy of life threatening diseases or life saving drugs

4. Potent drugs drug amount is very small

5. Drugs that show variability of drug conc. in plasma

Therapeutic Drug Monitoring (TDM)

3. Difficulty in ditinguishing between the effects of a disease and the toxic effects of a drug

Factors that modify drug plasma concentration for a given dose

• Drug formulation• Drug interaction

• Environmental factors• Genetic variation

• Renal and hepatic function

Reasons for monitoring drug treatment

1. To see whether there is therapeutic response

2. To assess drug toxicity

3. To assess compliance

Examples of difficulty in ditinguishing between the effects of a disease and

the toxic effects of a drug

Digoxin toxicity Congest.Heart Failure

Nausea / anorexia / arrythmias

1.

2. Gentamycin toxicity Gram (–) septicaemia

Renal damage

Pharmacokinetic parameters

Cmax (peak)

Half life

Time Cmin (trough)

Dru

gs- p

lasm

a c

onc.

AUC 24

Dru

g co

nc. (

mg /

l )

5

10

20

642Hours

Visualisation of half-life

2.5

t ½ t

½

t ½

First order elimination of a drug (t ½ : 2 hours)

The plasma conc. falls by half each half-life

Clinical application of half life (t½)

* Designing drug dosage regimen

* Determining time to reach steady state drug level which show clinical effect

* Determining time to reach the drug level which have no clinical effect anymore

CONSIDERATION

Ph’kinetic Ph’dynamic Ph’economic

RATIONAL & GOOD CLINICAL THERAPY

Tidak ada seorang jiwa pun, kecuali ada penjaganya

(Q:S : At Toriq:4)