Understanding the Different Types of Overactive Bladder Medications
To address the question of whether Myrbetriq can cause dementia, it's crucial to understand how it differs from older treatments for overactive bladder (OAB). Historically, the primary drug class used for OAB was anticholinergics (also called antimuscarinics), which work by blocking a neurotransmitter called acetylcholine. For years, studies have highlighted the potential cognitive risks associated with these drugs, particularly in older adults, because acetylcholine is critical for learning and memory. Myrbetriq (mirabegron) belongs to a newer class of drugs called beta-3 adrenergic receptor agonists.
Unlike anticholinergics, Myrbetriq does not block acetylcholine. Instead, it activates beta-3 adrenergic receptors found on the bladder's detrusor muscle, causing it to relax. This relaxation increases the bladder's capacity and reduces the symptoms of urgency and frequency without directly interfering with the cholinergic system in the brain, which is the mechanism thought to cause cognitive problems with anticholinergics.
Clinical Trial Findings on Myrbetriq and Cognitive Function
Multiple clinical studies have examined the cognitive safety of Myrbetriq, especially in older adults, who are most susceptible to cognitive decline. One key Phase 4 placebo-controlled study, known as PILLAR, investigated the cognitive effects of Myrbetriq in patients aged 65 and older with OAB.
The study, which was a 12-week trial involving hundreds of patients, used the Montreal Cognitive Assessment (MoCA), a sensitive tool for detecting mild cognitive impairment. The results demonstrated that Myrbetriq treatment had no adverse impact on cognitive function when compared to the placebo group. The study concluded that Myrbetriq represents a viable alternative to anticholinergic drugs for older patients with OAB, particularly those concerned about cognitive impairment. However, the authors noted the short duration of the study as a limitation, acknowledging that longer-term effects could not be fully captured.
Observational Studies and Emerging Evidence
While clinical trial data is reassuring, real-world observational studies offer a broader perspective, though they can be influenced by confounding factors. Several observational studies have been conducted comparing the cognitive outcomes of Myrbetriq users with those taking anticholinergics.
- Evidence supporting Myrbetriq's cognitive safety: A Canadian cohort study found that patients using OAB anticholinergics had a 23% higher risk of new-onset dementia compared to those taking Myrbetriq. Another Danish study also highlighted the importance of using an active comparator (Myrbetriq) rather than no treatment, finding no increased risk of dementia with anticholinergic use when compared directly to Myrbetriq. Overall, these studies tend to frame Myrbetriq as a safer alternative than anticholinergic medications.
- Conflicting and concerning findings: A large Korean cohort study published in 2024 presented more complex results, suggesting that both anticholinergics and Myrbetriq were associated with an increased risk of new-onset dementia when compared to a non-medicated group. The study found a dose-response relationship, with a higher cumulative dose of Myrbetriq correlating with an increased risk of dementia. However, the risk was most significantly elevated in patients taking a combination of Myrbetriq and an anticholinergic. A subsequent abstract from April 2025 discussing a Danish study also noted a significant association between mirabegron and dementia across all age groups and sexes when compared to untreated controls, though this was contrasted with another OAB drug, fesoterodine, which showed no association. These findings require further investigation and confirmation through additional studies.
- Special considerations: A case report described a patient with a prior concussion who developed neurocognitive side effects after starting Myrbetriq, suggesting that individuals with prior brain injuries might have different susceptibilities. This emphasizes the need for caution and personalized medicine in specific patient populations.
What This Means for Patients
The conflicting evidence, particularly between older studies and some very recent observational cohorts, makes it difficult to give a definitive answer. What is clear, however, is that Myrbetriq's mechanism of action is fundamentally different from anticholinergics, and clinical trials have not demonstrated a cognitive risk in older adults over the short term. The most concerning findings arise from specific, large observational studies, some of which suggest a potential risk with higher cumulative doses or, more notably, when Myrbetriq is used in combination with anticholinergics.
For patients with a history of cognitive issues, a high risk of dementia, or those already on multiple medications, Myrbetriq is generally considered a safer option than starting or continuing a highly anticholinergic OAB drug. However, the decision should be made in careful consultation with a healthcare provider who can weigh the benefits against any potential risks based on the patient's individual health profile.
Comparing Myrbetriq with Anticholinergics for OAB
| Feature | Myrbetriq (mirabegron) | Older Anticholinergic OAB Drugs (e.g., oxybutynin, tolterodine) |
|---|---|---|
| Drug Class | Beta-3 adrenergic receptor agonist | Anticholinergic (antimuscarinic) |
| Mechanism of Action | Relaxes the bladder detrusor muscle by activating beta-3 receptors. | Blocks acetylcholine receptors to inhibit bladder muscle contraction. |
| Cognitive Effect | Short-term clinical trials show no adverse cognitive impact. Some recent observational data suggests a potential long-term risk that requires more research. | Well-established association with cognitive impairment, especially in older adults. Higher anticholinergic burden increases risk. |
| Cognitive Safety Profile | Considered generally safer for cognitive health than anticholinergics, based on its different mechanism and lack of strong cholinergic blocking effects in the brain. | Less favorable, particularly in older adults or those with existing cognitive risk factors. Some newer anticholinergics may have lower CNS penetration. |
| Common Side Effects | Headache, nasopharyngitis, constipation, urinary tract infection, increased blood pressure. | Dry mouth, constipation, blurred vision, sleepiness, confusion. |
Conclusion
While Myrbetriq is not known to directly cause dementia, the relationship between overactive bladder medications and cognitive decline is complex and evolving. Unlike older anticholinergic drugs, Myrbetriq does not possess the same mechanism for blocking acetylcholine in the brain, and short-term clinical trials have not shown adverse cognitive effects in older adults. However, patients and doctors should be aware of some more recent observational data suggesting a possible long-term association, particularly with high cumulative doses or combination therapy with anticholinergics. Ultimately, a careful risk-benefit assessment, especially in elderly patients or those with existing cognitive issues, is necessary to determine the most appropriate treatment for overactive bladder.
