From the FDA Drug Label
Increases in Blood Pressure: Can increase blood pressure in adult or pediatric patients. *Includes reports of blood pressure above the normal range, and BP increased from baseline, occurring predominantly in subjects with baseline hypertension. The cause of hypertension in a patient after starting mirabegron (Myrbetriq) is increased blood pressure due to the medication itself, as it can increase blood pressure in adult or pediatric patients 1 1.
- Key points:
- Mirabegron can increase blood pressure
- Patients with baseline hypertension are more likely to experience increased blood pressure
- Periodic monitoring of blood pressure is recommended, especially in hypertensive patients
From the Research
Mirabegron can cause elevated blood pressure as a side effect, so I recommend monitoring the patient's blood pressure closely and considering dose reduction or discontinuation if hypertension persists. For patients with uncontrolled hypertension, mirabegron should be used with caution or avoided altogether. If the patient's blood pressure increase is significant (>10 mmHg systolic) or if they develop symptoms of hypertension, the medication should be discontinued. Alternative treatments for overactive bladder could include anticholinergics like solifenacin or darifenacin, which don't typically affect blood pressure. Behavioral modifications such as bladder training, pelvic floor exercises, and fluid management should also be emphasized. The mechanism behind mirabegron's effect on blood pressure relates to its action as a beta-3 adrenergic receptor agonist, which can cause peripheral vasodilation but may also have some activity on beta-1 receptors in the heart, potentially increasing cardiac output and blood pressure, as seen in a study published in 2022 2. Regular blood pressure monitoring is essential, particularly during the first few weeks of treatment when these effects are most likely to emerge. Some studies have shown that mirabegron does not have a significant impact on blood pressure, such as a study published in 2023 3, but others have found an increase in systolic blood pressure in some patients, such as the study published in 2022 2. However, a large, multinational study found no higher risk of major adverse cardiovascular events, acute myocardial infarction, stroke, cardiovascular mortality, or all-cause mortality among users of mirabegron relative to users of antimuscarinics 4. It's also worth noting that mirabegron has been shown to be effective and safe in certain populations, such as very older women with overactive bladder, as seen in a study published in 2023 3. In terms of specific patient populations, a study published in 2020 found that mirabegron was safe and effective in children with refractory neurogenic bladder dysfunction 5, and another study published in 2021 found that mirabegron add-on therapy to tamsulosin was well-tolerated in male patients with residual overactive bladder symptoms 6. Overall, while mirabegron can cause elevated blood pressure, the benefits of the medication may outweigh the risks for many patients, and regular monitoring and careful consideration of alternative treatments can help minimize the risks. Key points to consider when prescribing mirabegron include:
- Monitoring blood pressure closely, especially in patients with pre-existing hypertension
- Considering alternative treatments, such as anticholinergics or behavioral modifications, for patients with uncontrolled hypertension
- Being aware of the potential for increased systolic blood pressure in some patients
- Regularly reviewing the patient's medical history and current medications to minimize the risk of adverse interactions.