Interactions

Question 1

Inducers of the P450 system include - INR will decrease

Answer 1

antiepileptics: phenytoin, carbamazepine
barbiturates: phenobarbitone
rifampicin
St John’s Wort
chronic alcohol intake
griseofulvin
smoking (affects CYP1A2, reason why smokers require more aminophylline)

Question 2

Inhibitors of the P450 system include - INR will increase

Answer 2

antibiotics: ciprofloxacin, erythromycin
isoniazid
cimetidine,omeprazole
amiodarone
allopurinol
imidazoles: ketoconazole, fluconazole
SSRIs: fluoxetine, sertraline
ritonavir
sodium valproate
acute alcohol intake
quinupristin

Question 3

Beta-blockers plus WHAT never prescribed together….

Answer 3

ACEI