No, Do Not Increase Mirabegron Above 50 mg Daily
The maximum approved dose of mirabegron for overactive bladder in adults is 50 mg once daily, and you cannot increase beyond this dose. 1
FDA-Approved Dosing
According to the FDA prescribing information, the dosing algorithm for mirabegron in adults with OAB is straightforward 1:
- Starting dose: 25 mg once daily
- Maximum dose: 50 mg once daily (after 4-8 weeks if needed)
- No higher doses are approved for routine clinical use
What the Evidence Shows About Higher Doses
While 100 mg doses were studied in clinical trials, they are not FDA-approved for standard practice. Research shows 2, 3, 4:
- 100 mg mirabegron demonstrated efficacy in Phase II/III trials with dose-dependent improvements in incontinence and micturition frequency
- However, the 100 mg dose showed increased pulse rate changes compared to lower doses 2
- The risk-benefit profile favored the 50 mg dose for regulatory approval
One Japanese study allowed optional dose escalation to 100 mg in patients with insufficient response at week 8, showing acceptable tolerability 5. However, this remains investigational and is not part of standard FDA-approved dosing.
What To Do If 50 mg Is Insufficient
If your patient has inadequate response to mirabegron 50 mg monotherapy, the evidence-based next step is combination therapy, not dose escalation:
Add an antimuscarinic agent (solifenacin 5 mg) to mirabegron 50 mg 6:
- The SYNERGY I/II and BESIDE trials demonstrated that combination therapy (solifenacin 5 mg + mirabegron 50 mg) was statistically superior to either monotherapy for reducing incontinence episodes and micturitions
- Effect sizes were additive: combination therapy showed effect sizes of -0.65 to -0.70 for incontinence episodes versus -0.37 to -0.45 for monotherapies
- The combination was well-tolerated over 12 months, though dry mouth, constipation, and urinary retention events were slightly increased compared to monotherapy
Important Caveats
- Ensure your patient doesn't have moderate-to-severe renal impairment (eGFR 15-29 mL/min/1.73 m²), where the maximum dose is capped at 25 mg 1
- Similarly, moderate hepatic impairment (Child-Pugh Class B) limits the maximum dose to 25 mg 1
- Severe renal or hepatic impairment are contraindications to mirabegron use
Bottom Line
Stay at 50 mg maximum for monotherapy. If symptoms persist, add combination therapy with an antimuscarinic rather than attempting to exceed the approved maximum dose.