<p><strong>Effect of enzyme inhibitors</strong>: Mirabegron exposure (AUC) was increased 1.8-fold in the presence of the strong inhibitor of CYP3A/P-gp ketoconazole in healthy volunteers. No dose adjustment is needed when Mirabegron is combined with inhibitors of CYP3A and/or P-gp. However, in patients with mild to moderate renal impairment or mild hepatic impairment concomitantly receiving strong CYP3A inhibitors, such as itraconazole, ketoconazole, ritonavir and clarithromycin, the recommended dose is 25 mg once daily with or without food. Mirabegron is not recommended in patients with severe renal impairment or patients with moderate hepatic impairment concomitantly receiving strong CYP3A inhibitors.<br />
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<strong>Effect of enzyme inducers</strong>: Substances that are inducers of CYP3A or P-gp decrease the plasma concentrations of Mirabegron. No dose adjustment is needed for Mirabegron when administered with therapeutic doses of rifampicin or other CYP3A or P-gp inducers.<br />
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<strong>Effect of Mirabegron on CYP2D6 substrates</strong>: In healthy volunteers, the inhibitory potency of Mirabegron towards CYP2D6 is moderate and the CYP2D6 activity recovers within 15 days after discontinuation of Mirabegron. Multiple once daily dosing of Mirabegron IR resulted in a 90% increase in Cmax and a 229% increase in AUC of a single dose of metoprolol. Multiple once daily dosing of Mirabegron resulted in a 79% increase in Cmax and a 241% increase in AUC of a single dose of desipramine. Caution is advised if Mirabegron is co-administered with medicinal products with a narrow therapeutic index and significantly metabolised by CYP2D6, such as thioridazine, Type 1 C antiarrhythmics (e.g., flecainide, propafenone) and tricyclic antidepressants (e.g., imipramine, desipramine). Caution is also advised if Mirabegron is co-administered with CYP2D6 substrates that are individually dose titrated.<br />
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<strong>Effect of Mirabegron on transporters</strong>: Mirabegron is a weak inhibitor of P-gp. Mirabegron increased Cmax and AUC by 29% and 27%, respectively, of the P-gp substrate digoxin in healthy volunteers. For patients who are initiating a combination of Mirabegron and digoxin, the lowest dose for digoxin should be prescribed initially. Serum digoxin concentrations should be monitored and used for titration of the digoxin dose to obtain the desired clinical effect.<br />
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<strong>Other interactions</strong>: No clinically relevant interactions have been observed when Mirabegron was co-administered with therapeutic doses of solifenacin, tamsulosin, warfarin, metformin or a combined oral contraceptive medicinal product containing ethinylestradiol and levonorgestrel. Dose-adjustment is not recommended.</p>