May potentiate antihypertensive effects w/ drugs or other agents that lower BP. Additive hyperkalaemic effect w/ K supplements, K-sparing diuretics, or other drugs that can cause hyperkalaemia. Increased risk of renal impairment (particularly in those who are inadequately hydrated) & attenuated hypotensive effect w/ NSAIDs. Interactions may occur w/ drugs that affect cytochrome P450 isoenzymes.