Reversible increased serum conc & toxicity of lithium. Increased antihypertensive effect w/ baclofen. Attenuated antihypertensive effect w/ NSAIDs ie, ASA, COX-2 inhibitors, nonselective NSAIDs. Increased antihypertensive effect & risk of orthostatic hypotension w/ TCAs, neuroleptics. Increased risk of hyperkalaemia w/ aliskiren, K salts, K-sparing diuretics, ACE inhibitors, AIIAs, NSAIDs, heparins, immunosuppressants eg, ciclosporin or tacrolimus, trimethoprim, co-trimoxazole. Increased risk of hyperkalaemia, worsened renal function, CV morbidity & mortality w/ aliskiren. Increased risk of severe anaphylactoid reactions w/ extracorporeal treatments. Increased risk of angioneurotic oedema w/ estramustine. Additive hyperkalaemic effects w/ K-sparing diuretics (eg, triamterene, amiloride, eplerenone, spironolactone), K salts. Increased blood-glucose lowering effect w/ antidiabetics eg, insulins, oral hypoglycemics. Excessive BP reduction w/ non-K-sparing diuretics. Increased risk of angioedema w/ racecadotril, mTOR inhibitors (eg, sirolimus, everolimus, temsirolimus), gliptins (eg, linagliptin, saxagliptin, sitagliptin, vildagliptin); sacubitril/valsartan. Increased hypotensive effects by antihypertensives & vasodilators. Reduced BP w/ nitroglycerin & other nitrates or other vasodilators. Increased risk of leucopenia w/ allopurinol, cytostatic or immunosuppressive agents, systemic corticosteroids or procainamide. Enhanced hypotensive effects w/ anaesth drugs. Reduced antihypertensive effects w/ sympathomimetics, corticosteroids & systemic tetracosactide. Nitritoid reactions w/ injectable gold (Na aurothiomalate). Risk of hypokalemia w/ Torsade de pointes-inducing drugs eg, class IA & III antiarrhythmic agents, phenothiazines, benzamides, butyrophenones, other antipsychotics; bepridil, cisapride, diphemanil, IV erythromycin, halofantrine, mizolastine, moxifloxacin, pentamidine, sparfloxacin, IV vincamine, methadone, astemizole, terfenadine. Increased risk of low K levels by IV amphotericin B, glucocorticoids, systemic mineralocorticoids, tetracosactide, stimulant laxatives. Increased hypersensitivity reactions to allopurinol. Hypokalaemia &/or hypomagnesaemia predisposed to toxic effects of digitalis. Lactic acidosis due to metformin. Increased risk of acute renal insufficiency w/ high-dose iodinated contrast media. Reduced urine Ca elimination. Increased creatinine levels w/ ciclosporin, tacrolimus.