Interactions for enalaprilantacids: decrease effeciency of captopril. indomethacin: reduces hypotensive effect. digoxin: increases plasma digoxin levels. potassium preparations & potassium sparing diuretics: hyperkalaemia and increased risk of renal failure. lithium: toxicity due to increased serum concentration of lithium. immunosuppressive drugs : increased risk of bone marrow depression. antidepressants, diuretics, beta-blockers, nitrates, dopaminergics, calcium channel blockers, phenothiazines: enhance hypotensive effect. morphine: enhanced analgesic effect and respiratory depression.interactions for hydrochlorothiazidecholestyramine & colestipol: decrease absorption of hydrochlorothiazide. diazoxide: additive action - may cause hyperglycemia, hyperuricaemia and hypotension. digitalis: diuretics induced hypokalaemia may precipitate digitalis toxicity. lithium: hydrochlorothiazide potentiates therapeutic and toxic effects by increasing its renal excretion