K-sparing diuretics, K supplements or salt substitutes may lead to increases in serum K, & in heart failure patients, increases in serum creatinine. NSAID use may lead to increased risk of renal impairment & loss of antihypertensive effect. Dual inhibition of the Renin-Angiotensin System (RAS): Increased risk of renal impairment, hypotension, & hyperkalemia.