Drug Interactions Flashcards
Outline the phases of drug trials
Phase 1 = safety & toxicity in health subjects
Phase 2 = first assessment in patients, dose range identified
Phase 3 = tests efficacy in wider patient population
Phase 4 = post-marketing surveillance of adverse effects, efficacy, safety and toxicity
What is involved in phase 1 of drug trials?
Healthy human subjects to assess SAFETY and TOXICITY. About 100 subjects.
What is involved in phase 2 of drug trials?
DOSE RANGE IDENTIFIED in patients, monitor pharmacokinetics/dynamics. Usually about 500 subjects.
What is involved in phase 3 of drug trials?
TESTS EFFICACY, used in the wider patient population. Usually 2000 patients with multi-centre trials
What is involved in phase 4 of drug trials?
Post-marketing surveillance: efficacy, safety, toxicity and adverse effects monitored
Which drugs can interact with warfarin?
Cimetidine, erythromycin, ciprofloxacin, sulphonamides
Which drugs can interact with theophylline?
Cimetidine, erythromycin –> can cause convulsions/arrhythmias
Which drugs can interact with digoxin?
Amiodarone, verapamil, quinidine, diuretics –> arrhythmias and heart block
Which drugs can interact with beta-blockers?
Verapamil and diltiazem (non-dihydropyridine CCBs) –> bradycardia and systole
Which drugs can interact with lithium
Thiazide diuretics –> ataxia, convulsions
Which drugs can interact with azathioprine/mercaptopurine?
Allopurinol –> bone marrow failure
Which drugs can interact with phenytoin?
Isoniazide, sulphonamides -> ataxia
COCP –> reduced effect
Which anti-emetic drug accelerates gastric emptying?
Metoclopramide
