May increase incidence of hypotension, hyperkalemia & changes in renal function w/ ACE inhibitors or aliskiren. May increase serum K levels w/ K-sparing diuretics or K supplements, salt substitutes containing K or drugs that increase serum K levels (eg, heparin). May increase lithium conc & toxicity. Hypokalemia w/ corticosteroids, ACTH, amphotericin, penicillin G, carbenoxolone, antiarrhythmics. Hyponatremia w/ antidepressants, antipsychotics, antiepileptics. May decrease antihypertensive effects w/ NSAIDs including Cox-2 inhibitors. Electrolyte imbalance w/ digitalis glycosides. Other antihypertensives; insulin & oral antidiabetics; anionic exchange resins, allopurinol, amantadine, diazoxide, cytotoxic drugs, anticholinergic agents, vit D, Ca salts, ciclosporin, methyldopa, pressor amines (eg, noradrenaline), barbiturates, narcotics & alcohol. Valsartan: May increase systemic exposure w/ inhibitors of the uptake transporter (eg, rifampin, ciclosporin) or efflux transporter (ritonavir).