From the Guidelines
Myrbetriq (Mirabegron) works by relaxing the bladder muscle during the storage phase, increasing bladder capacity, and reducing the urge to urinate.
Mechanism of Action
- Mirabegron is a beta-3 adrenoceptor agonist, which means it targets the beta-3 receptors in the bladder muscle, causing it to relax and increasing its capacity to hold urine.
- This reduction in bladder muscle contractions leads to a decrease in the frequency and urgency of urination, as well as a reduction in episodes of urinary incontinence.
- The exact mechanism of how mirabegron affects the bladder muscle is not fully understood, but it is thought to involve the activation of beta-3 adrenoceptors, which increases the production of cyclic adenosine monophosphate (cAMP) and leads to the relaxation of the bladder muscle 1.
Clinical Evidence
- Studies have shown that mirabegron is effective in reducing symptoms of overactive bladder, including frequency, urgency, and urinary incontinence, in both men and women 1.
- Mirabegron has also been shown to be well-tolerated, with common side effects including hypertension, urinary tract infections, headache, and nasopharyngitis 1.
- The long-term efficacy and safety of mirabegron in men with lower urinary tract symptoms (LUTS) are not well-established, and further studies are needed to fully understand its effects in this population 1.
Key Points
- Mirabegron is a beta-3 adrenoceptor agonist that relaxes the bladder muscle and increases its capacity to hold urine.
- It is effective in reducing symptoms of overactive bladder, including frequency, urgency, and urinary incontinence.
- Mirabegron is well-tolerated, but its long-term efficacy and safety in men with LUTS are not well-established.
From the FDA Drug Label
Mirabegron is an agonist of the human beta-3 adrenergic receptor (AR) as demonstrated by in vitro laboratory experiments using the cloned human beta-3 AR. Mirabegron relaxes the detrusor smooth muscle during the storage phase of the urinary bladder fill-void cycle by activation of beta-3 AR which increases bladder capacity
- The mechanism of action of Myrbetriq (Mirabegron) is as a beta-3 adrenergic agonist.
- It works by relaxing the detrusor smooth muscle in the urinary bladder, which increases bladder capacity.
- This effect is achieved through the activation of beta-3 adrenergic receptors 2.
From the Research
Mechanism of Action of Myrbetriq (Mirabegron)
The mechanism of action of Myrbetriq (Mirabegron) is as a β₃-adrenoceptor agonist, which targets the β₃-adrenergic receptors in the bladder to relax the bladder muscle and increase bladder capacity 3, 4, 5, 6.
Key Effects
- Reduces bladder muscle contractions 6
- Increases bladder capacity 3, 4
- Reduces the number of incontinence episodes per 24 hours 4, 6
- Reduces micturitions per 24 hours 4, 6
Comparison to Antimuscarinic Agents
Mirabegron has a different mechanism of action from antimuscarinic agents, which makes it a valuable treatment option for patients who are intolerant of or have contraindications to anticholinergic agents 4, 6.
Pharmacokinetic Interactions
Mirabegron interacts with many other drugs via cytochrome P450 isoenzymes, which can lead to pharmacokinetic interactions with other drugs that are CYP2D6 substrates 3, 7.
Safety and Efficacy Profile
Mirabegron has been shown to be well tolerated and effective in reducing symptoms of overactive bladder, including urge urinary incontinence, urgency, and urinary frequency 3, 4, 5, 6. However, it may cause adverse effects such as hypertension, nasopharyngitis, and urinary tract infection 4, 7.