Increased antihypertensive effect w/ baclofen, amifostine. Further BP reduction w/ nitroglycerine & other nitrates or vasodilators. Reduced antihypertensive effects w/ corticosteroids, tetracosactide, sympathomimetics. Increased risk of orthostatic hypotension w/ α-blockers, TCAs, antipsychotics & anesth. Perindopril: Increased risk of hyperkalemia w/ aliskiren, K salts, K-sparing diuretics, ACE inhibitors, AIIAs, NSAIDs including aspirin ≥3 g/day, heparins, immunosuppressant agents eg, ciclosporin or tacrolimus, trimethoprim & co-trimoxazole. Hemodialysis. Potentially lethal hyperkalemia w/ K sparing diuretics. Increased risk of angioedema w/ sacubitril/valsartan, estramustine, mTOR inhibitors & gliptines. Increased lithium conc & toxicity. Increased risk of hypoglycemia w/ antidiabetic agents. Increased risk of worsening of renal function w/ NSAIDs. Nitritoid reactions w/ inj gold (Na aurothiomalate). Amlodipine: Lethal ventricular fibrillation & CV collapse associated w/ hyperkalemia w/ IV dantrolene. CYP3A4 inducers (eg, rifampicin, Hypericum perforatum
). Significant increase in exposure w/ strong or moderate CYP3A4 inhibitors. Increased blood levels of tacrolimus. Increased exposure of mTOR inhibitors. Increase trough conc of ciclosporin. Increased exposure of simvastatin. Increased BP lowering effects w/ grapefruit.