13 clinical pharmacokinetics Ngu

Question 1

link pharmacodynamics/kinetics with patient variability

Answer 1

inter-pt variable: 5-10% of pt will not respond to drug

intra-pt variable: pt may respond to drug with different pharmacodynamics/kinetics

pharmacokinetics: pt compliance/medication errors and health issues may affect some or all of the ADME steps

Question 2

What are the indications for therapeutic drug monitoring?

Answer 2

1- poor correlation with drug response and conc

2- narrow TI

3- individualized therapy

4- effects cannot be observed any other way

5- compliance

6- post dosage follow up

7- altered pKinetics

8- confirm toxicity

Question 3

What type of drugs are monitored clinically?

Answer 3

drugs with very narrow therapeutic indices ie. some antibiotics and anti seizure meds

Question 4

What are the steps of TDM?

Answer 4

1- request
2- sample from steady state (unless w/ loading dose or for toxicity)
3- record everything about drug and pt
4- lab measurements
5- communique with lab
6- clinical interpretation of lab results
7- therapeutic management –> modify dose as needed

Question 5

What factors affect TDM?

Answer 5

PK factors: Absorption, CL, Vd (indirectly t_1/2)

PD: Emax, tissue sensitivity