Mirabegron Considerations in Geriatric Patients
Mirabegron is well tolerated in elderly patients with multiple comorbidities, but should be used with caution in frail geriatric patients due to potential cardiovascular effects and requires dose adjustments for renal and hepatic impairment. 1, 2
Safety Profile in Geriatric Patients
- Mirabegron has a more favorable tolerability profile compared to antimuscarinic agents in older adults, with significantly lower rates of dry mouth, constipation, and cognitive effects 3
- The most common adverse events in geriatric patients include hypertension, urinary tract infections, headache, and nasopharyngitis 1
- Mirabegron does not affect voiding urodynamic parameters, and the overall change in post-void residual volume is small in elderly patients 1, 2
- In patients ≥65 years, dry mouth occurred with a six-fold higher incidence with tolterodine extended-release compared to mirabegron 25 mg or 50 mg 3
Dosing Considerations
- For geriatric patients with severe renal impairment (eGFR 15-29 mL/min/1.73 m²), the daily dose should not exceed 25 mg 4
- For geriatric patients with moderate hepatic impairment (Child-Pugh Class B), the daily dose should not exceed 25 mg 4
- Mirabegron is not recommended in patients with end-stage renal disease (eGFR <15 mL/min/1.73 m²) or severe hepatic impairment (Child-Pugh Class C) 4
- Starting with a lower dose (25 mg) may be appropriate in elderly patients, as studies have shown efficacy and safety at this dose 2, 5
Cardiovascular Considerations
- Mirabegron is contraindicated in patients with severe uncontrolled hypertension 1
- Regular blood pressure monitoring is recommended, especially during the initial treatment period 1
- A systematic review of the cardiovascular safety profile of mirabegron did not identify clinically significant effects on blood pressure or pulse rate at therapeutic doses in patients aged ≥65 years 3
Efficacy in Geriatric Populations
- Mirabegron has demonstrated significant improvements in overactive bladder symptoms in patients aged ≥80 years with multiple comorbidities 2
- Improvements in International Prostate Symptom Score (IPSS), Quality of Life index, and Patient Perception of Bladder Condition have been observed in older patients after 3 months of treatment 2
- Efficacy has been confirmed in patients aged ≥65 years with overactive bladder and incontinence in a 12-week phase IV study 6
Special Considerations for Frail Elderly
- The American Urological Association/Society of Urodynamics, Female Pelvic Medicine & Urogenital Reconstruction (AUA/SUFU) guidelines recommend caution when prescribing β3-adrenoceptor agonists in frail OAB patients 1
- Frail patients (those with mobility deficits, weight loss, weakness, and cognitive deficits) may have a lower therapeutic index and higher adverse event profile with OAB medications 1
- For patients who cannot tolerate pharmacologic management, behavioral strategies including prompted voiding and fluid management may be helpful 1
Polypharmacy Considerations
- Mirabegron may be a better option than antimuscarinic agents in elderly patients taking multiple medications, as it does not contribute to anticholinergic burden 3
- Regular medication reviews are recommended to assess for potential drug interactions 1
- Mirabegron has a different mechanism of action from antimuscarinic agents, which may make it suitable for patients who cannot tolerate anticholinergic side effects 7
Monitoring Recommendations
- Regular monitoring of blood pressure is recommended, especially in patients with pre-existing hypertension 1
- In men with lower urinary tract symptoms, regular re-evaluation of symptoms and post-void residual volume is advised 1
- Patients should be advised to discontinue medication if worsening voiding symptoms or urinary stream is noted after initiation of therapy 1