From the FDA Drug Label
Adult or Pediatric Patients Patients with Renal or Hepatic Impairment: Refer to the full prescribing information for recommended dosage. (2.4,2.5) Increases in Blood Pressure: Can increase blood pressure in adult or pediatric patients. Periodically monitor blood pressure, especially in hypertensive patients Mirabegron extended-release tablets are not recommended in patients with severe uncontrolled hypertension. (5.1) WARNINGS AND PRECAUTIONS Urinary Retention in Patients with Bladder Outlet Obstruction and in Patients Taking Muscarinic Antagonist Drugs for Overactive Bladder:Administer with caution in these patients because of risk of urinary retention. (5. 2) Angioedema:Angioedema of the face, lips, tongue and/or larynx has been reported with mirabegron. (5.3,6.2)
The safety of mirabegron in patients with complex medical conditions, such as Parkinson's disease and impaired renal or hepatic function, is not directly addressed in the provided drug label. However, it does mention that patients with renal or hepatic impairment should refer to the full prescribing information for recommended dosage 1. Additionally, the label warns about potential increases in blood pressure and the risk of urinary retention in certain patients, as well as the risk of angioedema.
- The label recommends caution when administering mirabegron to patients with certain conditions, but does not provide explicit information about its safety in patients with Parkinson's disease.
- Therefore, a conservative clinical decision would be to exercise caution when considering the use of mirabegron in patients with complex medical conditions, and to carefully monitor patients for potential adverse effects.
From the Research
Mirabegron is generally considered safe to use in patients with complex medical conditions, such as Parkinson's disease, but requires careful consideration and dose adjustments for renal and hepatic impairment. For patients with Parkinson's disease, mirabegron is considered safe as it doesn't cross the blood-brain barrier significantly or affect dopaminergic pathways 2. However, dose adjustments are necessary for renal and hepatic impairment. According to the study by 3, for severe renal impairment (eGFR 15-29 mL/min/1.73m²), the recommended dose is 25 mg daily, while mirabegron should be avoided in end-stage renal disease. In moderate hepatic impairment (Child-Pugh B), the dose should be limited to 25 mg daily, and it's not recommended for severe hepatic impairment (Child-Pugh C).
Key Considerations
- Blood pressure monitoring is important as mirabegron can cause hypertension, particularly in these vulnerable populations 4.
- Potential drug interactions should be evaluated, especially with medications metabolized by CYP2D6 4.
- Mirabegron works by activating beta-3 adrenergic receptors in the bladder, relaxing the detrusor muscle and increasing bladder capacity without significantly affecting voiding contractions, making it mechanistically different from anticholinergics that could worsen Parkinson's symptoms 5.
- A study published in 2019 found that mirabegron 25 mg once daily effectively decreased urgency symptoms in elderly OAB patients with CNS lesions after the 12-week treatment period, with minimal adverse effects 2.
Dosing and Administration
- The recommended dose for mirabegron is 25-50 mg daily, with dose adjustments necessary for renal and hepatic impairment 3.
- Mirabegron can be taken with or without food, and dose adjustment is not needed in relation to food intake 4.
Safety and Efficacy
- The safety and efficacy of mirabegron have been evaluated in several studies, including a large integrated clinical trial database of patients with overactive bladder receiving mirabegron, antimuscarinics, or placebo 5.
- No new safety concerns were identified, and mirabegron improved the symptoms of overactive bladder in patients with complex medical conditions, including Parkinson's disease 2.