Increased antihypertensive effect w/ baclofen. Increased hypotensive effects w/ antihypertensive agents (eg, β-blockers), vasodilators. Reduced BP w/ nitroglycerin, other nitrates or vasodilators. Increased antihypertensive effect & risk of orthostatic hypotension w/ α-blockers (eg, prazosin, alfuzosin, doxazosin, tamsulosin, terazosin); TCAs, antipsychotics, anaesth. Potentiated antihypertensive effect w/ amifostine. Increased risk of hyperkalaemia w/ aliskiren, K salts, K-sparing diuretics, ACE inhibitors, AIIAs, NSAIDs, heparins, immunosuppressants (eg, ciclosporin, 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 angioedema w/ sacubitril/valsartan; racecadotril, mTOR inhibitors (eg, sirolimus, everolimus, temsirolimus), gliptins (eg, linagliptin, saxagliptin, sitagliptin, vildagliptin). Increased risk of angioneurotic oedema w/ estramustine. Reversible increased serum conc & toxicity of lithium. Increased blood-glucose lowering effect of antidiabetic agents eg, insulin, oral hypoglycaemic agents. Excessive BP reduction w/ non-K-sparing diuretics. Attenuated antihypertensive effect w/ NSAIDs eg, ASA, COX-2 inhibitors, non-selective NSAIDs. Reduced antihypertensive effects w/ sympathomimetics, corticosteroids, tetracosactide. Nitritoid reactions w/ injectable gold (Na aurothiomalate). Risk of hyperkalaemia w/ dantrolene infusion. Varied conc w/ strong CYP3A4 inducers eg, rifampicin, Hypericum perforatum
. Increased amlodipine exposure w/ strong or moderate CYP3A4 inhibitors eg, PIs, azole antifungals, macrolides (eg, erythromycin or clarithromycin), verapamil or diltiazem. Increased risk of hypotension w/ clarithromycin. Additive BP-lowering effects to other antihypertensives. Increased tacrolimus blood levels. Increased exposure of mTOR inhibitors. Increased exposure to simvastatin. Increased bioavailability w/ grapefruit or grapefruit juice.