Risk of hyperkalaemia w/ salt substitutes containing K, K-sparing diuretics, ACE inhibitors, angiotensin II receptor antagonists, NSAIDs, including selective COX-2 inhibitors, heparin, immunosuppressives (cyclosporin or tacrolimus) & trimethoprim. Increases in serum lithium conc & toxicity. May reduce antihypertensive effect of COX-2 inhibitors & non-selective NSAIDs. Increase in AUC
0-24 & C
max of ramipril & ramiprilat. Vol depletion w/ high dose diuretics eg, furosemide (loop) & hydrochlorothiazide (thiazide). Potentiate hypotensive effects w/ baclofen, amifostine. Orthostatic hypotension may be aggravated by alcohol, barbiturates, narcotics, or antidepressants. Reduction of antihypertensive effect w/ corticosteroids (systemic route).