Reversible increased serum lithium conc & toxicity. Potentiated effect on serum K w/ other kaliuretic diuretics, laxatives, corticosteroids, ACTH, amphotericin, carbenoxolone, penicillin G Na, salicylic acid & derivatives. Increased serum K w/ ACE inhibitors, K-sparing diuretics, K supplements, K-containing salt substitutes, cyclosporin, heparin Na. Drugs affected by serum K disturbances eg, digitalis glycosides, antiarrhythmics, drugs inducing Torsade de pointes. Digitalis-induced arrhythmia w/ digitalis glycosides. Increased digoxin peak plasma conc. Increased hypotensive effects of other antihypertensive agents. Dosage adjustment of antidiabetics eg, oral agents, insulins. Risk of lactic acidosis w/ metformin. Impaired absorption w/ anionic exchange resins. Reduced diuretic, natriuretic & antihypertensive effects w/ NSAIDs. Decreased pressor amines effect. Potentiated non-depolarizing skeletal muscle relaxants effect. Increased hypersensitivity reactions of allopurinol. Increased serum Ca levels. Enhanced β-blockers & diazoxide hyperglycemic effect. Increased bioavailability w/ anticholinergics eg, atropine, biperiden. Increased risk of adverse effects by amantadine. Reduced renal excretion & potentiated myelosuppressive effects of cytotoxic agents eg, cyclophosphamide, methotrexate.