K supplements, K-sparing diuretics, salt substitute containing K, heparin, ACE inhibitors, lithium, other hypertensives (eg, α-blockers, diuretics), NSAIDs including COX-2 inhibitors, ASA & nonselective NSAIDs, antacid (Al-Mg hydroxide), diltiazem, ketoconazole, itraconazole, ritonavir, carbamazepine, phenobarb, phenytoin, fosphenytoin, primidone, rifampicin,
Hypericum perforatum, sildenafil.