Increased hypotensive effects w/ high-dose diuretics & other antihypertensives. Increased serum K w/ K-sparing diuretics, K supplements, K-containing salt substitutes or other drugs increasing K serum levels eg, heparin. Reversible increased serum lithium conc & toxicity. Attenuated antihypertensive effect w/ NSAIDs, selective COX-2 inhibitors, ASA & non-selective NSAIDs.