Increased antihypertensive effect w/ baclofen. Antihypertensive effect may be attenuated w/ NSAIDs eg, aspirin ≥3 g daily, COX-2 inhibitors & non-selective NSAIDs. Increased antihypertensive effect & risk of orthostatic hypotension w/ imipramine-like antidepressants (tricyclics), neuroleptics. Not recommended: Reversible increase in serum conc & toxicity of lithium. Perindopril: Higher frequency of adverse events w/ angiotensin II receptor-blockers or aliskiren. Increased risk of hyperkalaemia w/ aliskiren, K salts, K-sparing diuretics, ACE inhibitors, AIIA, NSAIDs, heparins, immunosuppressant agents (eg, ciclosporin or tacrolimus), trimethoprim. May increase blood-glucose lowering effect of antidiabetic agents eg, insulins, oral hypoglycaemic agents. Excessive BP reduction w/ non-K-sparing diuretics. Risk of hyperkalaemia w/ K-sparing diuretics eg, eplerenone, spironolactone. May increase risk of angioedema w/ racecadotril; mTOR inhibitors eg, sirolimus, everolimus, temsirolimus. May increase hypotensive effects w/ antihypertensive agents & vasodilators. May further reduce BP w/ nitroglycerin & other nitrates, or other vasodilatators. May increase risk of leucopenia w/ allopurinol, cytostatic or immunosuppressive agents, systemic corticosteroids or procainamide. May enhance hypotensive effects of certain anaesth drugs. Increased risk of angioedema w/ gliptins eg, linagliptin, saxagliptin, sitagliptin, vildagliptin. Antihypertensive effects may be reduced w/ sympathomimetics. Nitritoid reactions w/ injectable gold (Na aurothiomalate). Contraindicated: Risk of hyperkalaemia, worsening of renal function & increased CV morbidity & mortality w/ aliskiren in diabetic or impaired renal patients. Increased risk of severe anaphylactoid reactions w/ extracorporeal treatments. May increase risk of angioedema w/ sacubitril/valsartan. Not recommended: Risk of hyperkalaemia, worsening of renal function & increased CV morbidity & mortality w/ aliskiren in patients other than diabetic or impaired renal patients. Higher frequency of hypotension, syncope, hyperkalaemia, & worsening renal function w/ angiotensin-receptor blocker. Risk of increased angioneurotic oedema w/ estramustine. May increase risk of hyperkalaemia w/ co-trimoxazole. Hyperkalaemia w/ K-sparing diuretics (eg, triamterene, amiloride) & K salts. Indapamide: Risk of hypokalaemia w/ torsades de pointes-inducing drugs eg, class IA (eg, quinidine, hydroquinidine, disopyramide) & III (amiodarone, dofetilide, ibutilide, bretylium, sotalol) antiarrhythmic agents, neuroleptics (eg, chlorpromazine, cyamemazine, levomepromazine, thioridazine, trifluoperazine), benzamides (eg, amisulpride, sulpiride, sultopride, tiapride), butyrophenones (eg, droperidol, haloperidol), other neuroleptics (eg, pimozide), others (eg, bepridil, cisapride, diphemanil, IV erythromycin, halofantrine, mizolastine, moxifloxacin, pentamidine, sparfloxacin, IV vincamine, methadone, astemizole, terfenadine). Increased risk of low K levels w/ K-lowering drugs eg, amphotericin B (IV), glucocorticoids & mineralocorticoids (systemic), tetracosactide, stimulant laxatives. Toxic effects due to low K levels may occur w/ digitalis. May increase incidence of hypersensitivity reactions to allopurinol. Hypokalaemia or hyperkalaemia w/ K-sparing diuretics eg, amiloride, spironolactone, triamterene. Lactic acidosis w/ metformin caused by possible functional renal insufficiency linked to loop diuretics. Increased risk of acute renal insufficiency w/ high-dose iodinated contrast media. Risk of increased Ca levels w/ Ca salts. Risk of increased creatinine levels w/ ciclosporin, tacrolimus. Reduced antihypertensive effect w/ corticosteroids, tetracosactide (systemic route).