Drug Interaction Flashcards
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.
Plasma concentration
Efficacy or adverse effects
What are the 2 main types of drug interaction
Pharmacokinetic DI
Pharmacodynamic DI
Pharmacokinetic DI:occurs when one ormore drug alters the __________, __________, ___________ or _____________ of another drug such that its plasma concentration is altered
absorption, distribution, metabolism or excretion
PharmacodynamicD:I occurs when one or more drugs alters the __________ or ________ effects of another
Pharmacological or toxic
In the alteration of absorption
- Calcium containing drugs (Antacids) vs tetracycline
Calcium chelates tetracycline (antibiotic) to form a complex and prevent its absorption thereby reducing its plasma conc
In the alteration of metabolism
- Efavirenz vs artemether/lumefantrine
efavirenz (anti retroviral drug) inhibits cytochrome P3A4 enzyme which metabolises the antimalarial drug thereby reducing their plasma conc
In Additive toxicity
- Concomitant use of NSAIDs and glucocorticoids
increases the risk of gastric bleeding and worsens peptic ulcer disease
Concomitant administration of ascorbic acid or other antioxidants with artemisinin based combination therapy (ACT) in the treatment of malaria will lead to
Therapeutic failure/Reduction in efficacy