Indapamide: Increased of plasma lithium. Increased risk of ventricular arrhythmias w/ Torsades de pointes-inducing drugs eg, class Ia (quinidine, hydroquinidine, disopyramide) & class III antiarrhythmics (amiodarone, sotalol, dofetilide, ibutilide), some antipsychotics eg, phenothiazines (chlorpromazine, cyamemazine, levomepromazine, thioridazine, trifluoperazine), benzamides (amisulpride, sulpiride, sultopride, tiapride), butyrophenones (droperidol, haloperidol); bepridil, cisapride, diphemanil, erythromycin IV, halofantrine, mizolastine, pentamidine, sparfloxacin, moxifloxacin, vincamine IV. Reduced antihypertensive effect w/ NSAIDs (systemic route) including COX-2 selective inhibitors, high dose salicylic acid (≥3 g/day). Risk of sudden hypotension &/or acute renal failure w/ ACE inhibitors. Increased risk of hypokalaemia w/ amphotericin B (IV), gluco- & mineralo-corticoids (systemic route), tetracosactide, stimulant laxatives. Increased antihypertensive effect w/ baclofen. Increased incidence of hypersensitivity reactions to allopurinol. Increased risk of metformin induced lactic acidosis. Increased risk of acute renal failure w/ iodinated contrast media. Increased antihypertensive effect & risk of orthostatic hypotension w/ imipramine-like antidepressants, neuroleptics. Risk of hypercalcaemia w/ Ca (salts). Risk of increased plasma creatinine w/ ciclosporin, tacrolimus. Decreased antihypertensive effect w/ corticosteroids, tetracosactide (systemic route). Digitalis prep. K-sparing diuretics (amiloride, spironolactone, triamterene). Amlodipine: Risk of hyperkalaemia w/ dantrolene (infusion). Increased bioavailability w/ grapefruit or grapefruit juice. Increased exposure w/ strong or moderate CYP3A4 inhibitors (PIs, azole antifungals, macrolides-like erythromycin or clarithromycin, verapamil or diltiazem). Decreased plasma conc w/ CYP3A4 inducers (eg, rifampicin, Hypericum perforatum
). Increased exposure of simvastatin. Additive effect w/ other antihypertensive drugs.