Mirabegron

Generic name: mirabegron
Brand names: Myrbetriq, Myrbetriq Granules
Dosage forms: oral suspension, extended release (8 mg/mL); oral tablet, extended release (25 mg; 50 mg)
Drug class: Urinary antispasmodics

Medically reviewed by  A Ras MD.

What is mirabegron used for?

Mirabegron is a prescription medicine that is used to treat an overactive bladder.

Description

MYRBETRIQ (mirabegron extended-release tablets) for oral use and MYRBETRIQ Granules (mirabegron for extended-release oral suspension) are beta-3 adrenergic agonists.

The chemical name of mirabegron is 2-(2-aminothiazol-4-yl)-N-[4-(2-{[(2R)-2-hydroxy-2-phenylethyl]amino}ethyl)phenyl]acetamide having an empirical formula of C21H24N4O2S and a molecular weight of 396.51. The structural formula of mirabegron is:

Mirabegron

Mirabegron is a white powder. It is practically insoluble in water (0.082 mg/mL). It is soluble in methanol and dimethyl sulfoxide.

Each MYRBETRIQ (mirabegron extended-release tablets) for oral use contains either 25 mg or 50 mg of mirabegron and the following inactive ingredients: butylated hydroxytoluene, hydroxypropyl cellulose, hypromellose, magnesium stearate, polyethylene glycol, polyethylene oxide, red ferric oxide (25 mg tablet only), and yellow ferric oxide.

Each bottle of MYRBETRIQ Granules (mirabegron for extended-release oral suspension) contains approximately 8.3 g of granules, which contain 830 mg of mirabegron, and the following inactive ingredients: acesulfame potassium, diluted hydrochloric acid, ethylparaben, hypromellose, magnesium stearate, mannitol, methylparaben, silicon dioxide, simethicone, sodium polystyrene sulfonate, and xanthan gum. After reconstituted with 100 mL water, the suspension contains 8 mg/mL of mirabegron.

Mechanism of Action

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. Although mirabegron showed very low intrinsic activity for cloned human beta-1 AR and beta-2 AR, results in humans indicate that beta-1 AR stimulation occurred at a mirabegron dose of 200 mg.

Before taking mirabegron, tell your doctor:

  • If you are allergic to mirabegron; any part of this medicine; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.
  • If you have any of these health problems: Kidney disease or liver disease.
  • If you have high blood pressure.

This is not a list of all drugs or health problems that interact with mirabegron.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take mirabegron with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take mirabegron?

  • Tell all of your health care providers that you take mirabegron. This includes your doctors, nurses, pharmacists, and dentists.
  • It may take several weeks to see the full effects.
  • High blood pressure has happened with mirabegron. Have your blood pressure checked as you have been told by your doctor.
  • Tell your doctor if you are pregnant or plan on getting pregnant. You will need to talk about the benefits and risks of using mirabegron while you are pregnant.
  • Tell your doctor if you are breast-feeding. You will need to talk about any risks to your baby.

How is mirabegron best taken?

Use mirabegron as ordered by your doctor. Read all information given to you. Follow all instructions closely.

  • Take with or without food.
  • Swallow whole. Do not chew, break, or crush.
  • Take with a full glass of water.

What do I do if I miss a dose?

  • Skip the missed dose and go back to your normal time.
  • Do not take 2 doses at the same time or extra doses.

What are the side effects of mirabegron that I need to call my doctor about immediately?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
  • Signs of a urinary tract infection (UTI) like blood in the urine, burning or pain when passing urine, feeling the need to pass urine often or right away, fever, lower stomach pain, or pelvic pain.
  • Signs of high blood pressure like very bad headache or dizziness, passing out, or change in eyesight.
  • A fast heartbeat.
  • A heartbeat that does not feel normal.
  • Trouble passing urine.
  • Bladder irritation.
  • A very bad reaction called angioedema has happened with mirabegron. Sometimes, this may be life-threatening. Signs may include swelling of the hands, face, lips, eyes, tongue, or throat; trouble breathing; trouble swallowing; or unusual hoarseness. Get medical help right away if you have any of these signs.

What are some other side effects of mirabegron?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

  • Headache.
  • Nose and throat irritation.
  • Dry mouth.
  • Flu-like signs.
  • Back pain.
  • Dizziness.
  • Joint pain.
  • Constipation.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https://www.fda.gov/medwatch.

If overdose is suspected:

If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

How do I store and/or throw out mirabegron?

  • Store at room temperature.
  • Store in a dry place. Do not store in a bathroom.
  • Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
  • Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.

 

SRC: NLM .