Drug Interaction

Question 1

Drug interaction is the interplay between two or more drugs which alters the ________ _____________ of one or more drugs and may increase or decrease the _________ or ________ _______ of the drugs.

Answer 1

Plasma concentration

Efficacy or adverse effects

Question 2

What are the 2 main types of drug interaction

Answer 2

Pharmacokinetic DI
Pharmacodynamic DI

Question 3

Pharmacokinetic DI:occurs when one ormore drug alters the __________, __________, ___________ or _____________ of another drug such that its plasma concentration is altered

Answer 3

absorption, distribution, metabolism or excretion

Question 4

PharmacodynamicD:I occurs when one or more drugs alters the __________ or ________ effects of another

Answer 4

Pharmacological or toxic

Question 5

In the alteration of absorption
- Calcium containing drugs (Antacids) vs tetracycline

Answer 5

Calcium chelates tetracycline (antibiotic) to form a complex and prevent its absorption thereby reducing its plasma conc

Question 6

In the alteration of metabolism
- Efavirenz vs artemether/lumefantrine

Answer 6

efavirenz (anti retroviral drug) inhibits cytochrome P3A4 enzyme which metabolises the antimalarial drug thereby reducing their plasma conc

Question 7

In Additive toxicity
- Concomitant use of NSAIDs and glucocorticoids

Answer 7

increases the risk of gastric bleeding and worsens peptic ulcer disease

Question 8

Concomitant administration of ascorbic acid or other antioxidants with artemisinin based combination therapy (ACT) in the treatment of malaria will lead to

Answer 8

Therapeutic failure/Reduction in efficacy