Myrbetriq (mirabegron) selective beta-3 adrenoceptor (Beta3-AR) agonist. The drug activates Beta3-ARs on the detrusor muscle of the bladder to facilitate filling of the bladder and storage of urine.
Myrbetriq is specifically indicated for the treatment of overactive bladder (OAB) with symptoms of urge urinary incontinence, urgency, and urinary frequency.
Myrbetriq is supplied as an extended release tablet designed for oral administration. The recommended initial dose of the drug is is 25 mg once daily, with or without food. This starting dose is effective within 8 weeks. Based on individual efficacy and tolerability, it may be increased to 50 mg once daily. It should be swallowed whole with water.
The FDA approval of Myrbetriq was based on the results of three, 12-week, double-blind, randomized, placebo-controlled, parallel group, multicenter clinical trials in subjects with overactive bladder with symptoms of urge urinary incontinence, urgency, and urinary frequency. In Study 1, subjects were randomized to placebo, Myrbetriq 50 mg, Myrbetriq 100 mg, or an active control once daily. In Study 2, subjects were randomized to placebo, Myrbetriq 50 mg or Myrbetriq 100 mg once daily. In Study 3, subjects were randomized to placebo, Myrbetriq 25 mg or Myrbetriq 50 mg once daily. The co-primary efficacy endpoints in all three trials were change from baseline to end of treatment (Week 12) in mean number of incontinence episodes per 24 hours and change from baseline to end of treatment (Week 12) in mean number of micturitions per 24 hours, based on a 3-day micturition diary. An important secondary endpoint was the change from baseline to end of treatment (Week 12) in mean volume voided per micturition. Myrbetriq 25 mg was effective in treating the symptoms of OAB within 8 weeks, and Myrbetriq 50 mg was effective in treating the symptoms of OAB within 4 weeks. Efficacy of both 25 mg and 50 mg doses of Myrbetriq was maintained through the 12-week treatment period.
Adverse reactions associated with the use of Mybetriq may include, but are not limited to, the following:
Myrbetriq (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.
For additional information regarding Myrbetriq or overactive bladder, please visit the Myrbetriq web page.