Mirabegron

About Mirabegron

Mirabegron is a beta-3 adrenergic agonist that relaxes the bladder muscle; it works differently from antimuscarinic bladder drugs such as oxybutynin and solifenacin. Myrbetriq is labeled for overactive bladder with urge incontinence, urgency and frequency in adults, alone or combined with solifenacin, and for neurogenic detrusor overactivity (bladder overactivity caused by a nerve condition) in children 3 and older: the tablets for those weighing at least 35 kg, and Myrbetriq Granules, an extended-release suspension, dosed by weight. Adults start at 25 mg once a day, and after 4 to 8 weeks the dose may rise to the 50 mg maximum; the combination starts with mirabegron 25 mg and solifenacin 5 mg. In adults, severe kidney impairment (eGFR 15 to 29) or moderate liver impairment caps the dose at 25 mg, and it is not recommended with an eGFR below 15, dialysis or severe liver impairment. MedlinePlus says the full benefit may take 8 weeks or longer.

There is no boxed warning, and allergy to mirabegron or an ingredient is the only contraindication. Mirabegron can raise blood pressure, so the label recommends periodic checks, especially with hypertension, and does not recommend it with severe uncontrolled hypertension (in adults, a systolic pressure of 180 mm Hg or more, or a diastolic pressure of 110 mm Hg or more). Urinary retention has been reported in people with bladder outlet obstruction and in those taking antimuscarinic bladder drugs, so it is given to them with caution. Angioedema of the face, lips, tongue or larynx has been reported; swelling of the tongue or throat means stopping it at once and getting emergency help. In adults taking it alone, the most common side effects were high blood pressure, nasopharyngitis (cold symptoms), urinary tract infection and headache; with solifenacin they were dry mouth, urinary tract infection, constipation and a fast heartbeat.

Myrbetriq tablets and Myrbetriq Granules are different products that are not substituted milligram for milligram, and the label says not to combine them. The pharmacy mixes the granules with water when dispensing; the suspension is taken with food, measured with an oral dosing device, taken within an hour of measuring a dose, and kept at room temperature for up to 28 days. Generic tablets rated equivalent to Myrbetriq are sold, but some generic labels leave out the solifenacin combination or the pediatric use, which remain on the Myrbetriq label. The label reports no studies in pregnant women and no data on mirabegron in breast milk.

Taking Mirabegron

How to take it

Once a day. Swallow tablets whole with water; adults may take them with or without food, and children take them with food. Take the suspension with food: shake the bottle as directed, measure the dose with the oral dosing device, and take it within an hour of measuring it.

If you miss a dose

Take a missed dose as soon as you remember, unless more than 12 hours have passed; then skip it and take the next dose at the usual time. Do not take a double dose.

Storage

Tablets at room temperature, away from excess heat and moisture (not in the bathroom), out of reach of children. Keep the mixed suspension at room temperature and throw away what is left 28 days after the pharmacy prepares it.

Interactions to know about

Mirabegron is a moderate CYP2D6 inhibitor and raises levels of drugs such as metoprolol and desipramine, so narrow-margin CYP2D6 drugs may need monitoring and dose changes. With digoxin, the lowest dose of digoxin is considered first and blood levels guide changes. Antimuscarinic bladder drugs add to the risk of urinary retention, and its effect on warfarin has not been fully studied.

This summarizes the official prescribing information. Your prescriber’s and pharmacist’s instructions, and the leaflet that comes with your medicine, take priority.

Why the cash price for Mirabegron differs from pharmacy to pharmacy

Generic mirabegron tablets come from several makers while Myrbetriq is still sold, so quotes differ by whether the generic or the brand is dispensed, by each pharmacy’s fee and markup, and by whether the prescription allows substitution; one that names Myrbetriq and blocks substitution is filled with the brand.

The granules have a rated generic and are quoted by the bottle. A child’s dose is set by weight and each mixed bottle keeps 28 days, so the dose shapes how many bottles a month the quote covers. Tablets and granules are different products, so a pharmacist does not switch between them without the prescriber.

Ways to pay less for Mirabegron without insurance

• Check that the prescription allows a generic, unless the prescriber has a reason to require Myrbetriq.
• Compare more than one pharmacy, and ask whether each quote is for the generic or the brand.
• Once your dose is settled, ask the prescriber whether a ninety-day supply of tablets suits you.
• For a child’s suspension, ask how many bottles a month the dose needs, so the quote covers all of them.
• Upload the prescription to Script Unlock so licensed pharmacies can quote their cash price. You pay the pharmacy directly.

Questions to ask your pharmacist about Mirabegron

1. 1.How often should my blood pressure be checked while I take it?
2. 2.Do any of my medicines, such as metoprolol or digoxin, interact with it?
3. 3.Is my prescription being filled with the generic or with Myrbetriq?
4. 4.How do I measure my child’s suspension, and when do I throw the bottle away?

Related medications