Increased BP-lowering effects w/ other antihypertensives. Increased risk of hypotension, hyperkalemia & decreased renal function w/ angiotensin-receptor blockers, ACE inhibitors or aliskiren. Increased serum K w/ K-sparing diuretics, K supplements, K-containing salt substitutes or other medicinal products increasing serum K eg, heparin. Increased serum lithium conc & toxicity. Attenuated antihypertensive effect w/ NSAIDs including selective COX-2 inhibitors, acetylsalicylic acid (>3 g daily) & non-selective NSAIDs. Reduced systemic exposure, peak plasma conc & t½
w/ colesevelam HCl. Reduced bioavailability w/ Al Mg hydroxide antacids. Increased exposure w/ strong or moderate CYP3A4 inhibitors eg, PIs, azole antifungals, macrolides, verapamil, diltiazem. Varied plasma conc w/ strong CYP3A4 inducers eg, rifampicin, Hypericum perforatum
. Increased bioavailability w/ grapefruit of grapefruit juice. Risk of hyperkalaemia w/ dantrolene infusion. Increased exposure to simvastatin & cyclosporine. Increased tacrolimus blood levels.