Increased BP lowering effect w/ other antihypertensive (eg, α-blockers, diuretics). May cause higher frequency of adverse events (eg, hypotension, hyperkalaemia & decreased renal function including acute renal failure) w/ ACE inhibitors, ARBs or aliskiren. Increase in K serum w/ K-sparing diuretics, K supplements, salt substitutes containing K or other drugs that may increase serum K levels (eg, heparin). Reversible increase in serum lithium conc. May increase the risk of worsening of renal function & may lead to an increase in serum K w/ NSAIDs. Reduced systemic exposure & peak plasma conc w/ bile acid sequestering agent colesevelam HCl. Decreased bioavailability w/ antacids. Amlodipine: Increased exposure w/ strong or moderate CYP3A4 inhibitors (PIs, azole antifungals, macrolides eg, erythromycin or clarithromycin, verapamil or diltiazem). Decreased plasma conc w/ CYP3A4 inducers (eg, rifampicin,
Hypericum perforatum). Increased bioavailability w/ grapefruit or grapefruit juice. Concomitant use w/ simvastatin increases exposure to simvastatin. Coadministration w/ tacrolimus increases tacrolimus blood level. Concomitant use w/ cyclosporine may increase exposure to cyclosporine.