<p>Concurrent treatment with NSAIDs reduces hypotensive action and increases the risk of nephrotoxicity. Additive hyperkalaemic effect with K supplements, K-sparing diuretics, and other drugs (e.g. heparin). May increase risk of leucopenia with procainamide, allopurinol, cytostatic or immunosuppressants. May increase risk of lithium toxicity. Increased risk of nitritoid reactions with gold (Na aurothiomalate).</p>