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. Favoured 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.