Mirabegroninteractions

Drugs Metabolized by CYP2D6: Mirabegron is a CYP2D6 inhibitor and, when used concomitantly with drugs metabolized by CYP2D6, especially narrow therapeutic index drugs, appropriate monitoring and possible dose adjustment of those drugs may be necessary.

Digoxin: When initiating a combination of mirabegron and digoxin, use the lowest dose of digoxin; monitor serum digoxin concentrations to titrate digoxin dose to desired clinical effect. Pediatric use information is approved for Astellas Pharma Global Development, Inc.'s MYRBETRIQ (mirabegron extended-release tablets). However, due to Astellas Pharma Global Development, Inc.'s marketing exclusivity rights, this drug product is not labeled with that information. Drug interaction studies were conducted in adult patients to investigate the effect of coadministered drugs on the pharmacokinetics of mirabegron and the effect of mirabegron on the pharmacokinetics of coadministered drugs (e.g., ketoconazole, rifampin, solifenacin succinate, tamsulosin, and oral contraceptives). No dose adjustment is recommended when these drugs are coadministered with mirabegron. The following are drug interactions for which monitoring is recommended:

7.1 Drugs Metabolized by CYP2D6

Since mirabegron is a moderate CYP2D6 inhibitor, the systemic exposure of drugs metabolized by CYP2D6 enzyme is increased when coadministered with mirabegron. Therefore, appropriate monitoring and dose adjustment may be necessary when mirabegron extended-release tablet is coadministered with these drugs, especially with narrow therapeutic index CYP2D6 substrates.

7.2 Digoxin

When given in combination, 100 mg mirabegron increased mean digoxin C max from 1.01 to 1.3 ng/mL (29%) and AUC from 16.7 to 19.3 ng.h/mL (27%). For patients who are initiating a combination of mirabegron and digoxin, the lowest dose for digoxin should initially be considered. Serum digoxin concentrations should be monitored and used for titration of the digoxin dose to obtain the desired clinical effect.

7.3 Warfarin

The mean C max of S - and R -warfarin was increased by approximately 4% and AUC by approximately 9% when administered as a single dose of 25 mg after multiple doses of 100 mg mirabegron. Following a single dose administration of 25 mg warfarin, mirabegron had no effect on the warfarin pharmacodynamic endpoints such as International Normalized Ratio (INR) and prothrombin time. However, the effect of mirabegron on multiple doses of warfarin and on warfarin pharmacodynamic end points such as INR and prothrombin time has not been fully investigated.