Increased peak plasma & trough conc of digoxin. Increased risk of hyperkalaemia w/ other medicinal products that may also provoke hyperkalaemia [salt substitutes containing K, K-sparing diuretics, ACE inhibitors, AIIA, NSAIDs including selective COX-2 inhibitors, heparin, immunosuppressives (cyclosporin or tacrolimus), & trimethoprim]. Reversible increases in serum lithium conc & toxicity. Reduced antihypertensive effect w/ NSAIDs. May result in further deterioration of renal function, including possible acute renal failure, w/ COX inhibitors. Risk of vol depletion & hypotension w/ high dose diuretics eg, furosemide & hydrochlorothiazide. Increased BP-lowering effect w/ other antihypertensives. Higher frequency of adverse events w/ ACE inhibitors, ARBs or aliskiren. Potentiated hypotensive effects w/ baclofen or amifostine. Aggravated orthostatic hypotension w/ alcohol, barbiturates, narcotics, or antidepressants. Reduced antihypertensive effect w/ systemic corticosteroids.