Increased risk of toxicity of lithium. Concomitant use w/ drugs acting on RAS or ACE inhibitors w/ aliskiren. K-supplements, K-sparing diuretics, salt substitutes containing K or drugs that may alter K levels (eg, heparin). May increase risk of worsening of renal function w/ NSAIDs. Increased valsartan systemic exposure w/ uptake transporter inhibitors (eg, rifampin, ciclosporin) or efflux transporter. May potentiate skeletal muscle relaxant eg, curare derivatives action. Hypokalemic effect may be increased w/ kaliuretic diuretics, corticosteroids, ACTH, amphotericin, carbenoxolone, penicillin G, salicylic acid derivatives or antiarrhythmics. Hyponatremic effect may be intensified by antidepressants, antipsychotics, antiepileptics. Glucose tolerance may be altered w/ insulin & oral antidiabetics. Hypokalemia or hypomagnesemia may occur w/ digitalis glycosides. Diuretic & antihypertensive activity may weaken w/ NSAIDs (eg, salicylic acid derivative, indomethacin). Hypersensitivity reactions may increase w/ allopurinol. May increase risk of adverse effects caused by amantadine. Renal excretion may be reduced & enhance myelosuppresive effects of antineoplastic agents (eg, cyclophosphamide, methotrexate). Bioavailability may be increased by anticholinergics (eg, atropine, biperiden); may be decreased by prokinetics eg, cisapride. Absorption may be decreased by cholestyramine or colestipol. Rise in serum Ca may be potentiated w/ vit D or w/ Ca salts. Risk of hyperurecemia & gout complications may increase w/ ciclosporin. Hypercalcemia may occur w/ Ca salts. May enhance hyperglycaemic effect of diazoxide. Hemolytic anemia may occur w/ methyldopa. Orthostatic hypotension may be potentiated w/ alcohol, barbiturates or narcotics.