P-gp or strong CYP3A4 inhibitors eg, clarithromycin, cyclosporin, erythromycin, verapamil & diltiazem, telithromycin, ketoconazole, itraconazole, HIV PIs & nefazodone. Increased serum uric acid w/ thiazide diuretics. Impaired vit B
12 absorption. Colchicine toxicity w/ tolbutamide. Avoid use w/ grapefruit & grapefruit juice.