Increased plasma conc of carbamazepine, terfenadine, omeprazole. Increased serum conc of digoxin; cyclosporine, tacrolimus, hexobarbital, phenytoin, alfentanil, quinidine/disopyramide, lovastatin, bromocriptine, valproate, astemizole & other CYP450-metabolised drugs. Decreased serum conc by rifabutin or rifampin. Increased AUC of theophylline. Potentiated effects of warfarin. Acute ergot toxicity w/ ergotamine or dihydroergotamine. Severe adverse effects w/ non-sedative antihistamines, astemizole, terfenadine & cisapride. Lowered Cmax
, AUC & tmax
of zidovudine. Increased plasma conc by Maalox, ranitidine, omeprazole.