Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes Myrbetriq (Mirabegron). If you are concerned about side effects, discuss the risks and benefits of Myrbetriq (Mirabegron) with your doctor.

The following side effects have been reported by at least 1% of people taking Myrbetriq (Mirabegron). Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• Constipation
• Diarrhea
• dizziness
• headache
• increased blood pressure
• itching
• nausea
• symptoms of a cold (e.g., congestion, runny nose, sore throat)

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• symptoms of a urinary tract infection (e.g., pain when urinating, urinating more often than usual, low back or flank pain)

Stop taking the medication and seek immediate medical attention if any of the following occur:

• fast and irregular heartbeat
• Hives or rash
• signs of angiodema (e.g., swelling of the face, mouth, hands, or feet; difficulty breathing)
• signs and symptoms of a Stroke (e.g., sudden numbness or weakness in face, arm, or leg; slurred speech, vision changes, headache)
• urinary retention (not able to urinate)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking Myrbetriq (Mirabegron).

25 mg
Each oval, brown, film-coated, extended-release tablet debossed with "325" and the Astellas logo, contains 25 mg Myrbetriq (Mirabegron). Non-medicinal ingredients: polyethylene oxide, polyethylene glycol, hydroxypropyl cellulose, butylated hydroxytoluene, magnesium stearate, hypromellose, yellow ferric oxide, and red ferric oxide.

50 mg
Each oval, yellow, film-coated, extended-release tablet debossed with "355" and the Astellas logo, contains 50 mg Myrbetriq (Mirabegron). Non-medicinal ingredients: polyethylene oxide, polyethylene glycol, hydroxypropyl cellulose, butylated hydroxytoluene, magnesium stearate, hypromellose, and yellow ferric oxide.

Do not use Myrbetriq (Mirabegron) if you:

• are allergic to Myrbetriq (Mirabegron) or any ingredients of the medication
• are pregnant
• have severe, uncontrolled hypertension (high blood pressure)

There may be an interaction between Myrbetriq (Mirabegron) and any of the following:

• aclidinium
• Alfuzosin
• Amiodarone
• antihistamines (e.g., cetirizine, doxylamine, Diphenhydramine, Hydroxyzine, Loratadine)
• antipsychotics (e.g., chlorpromazine, Clozapine, pimozide, Haloperidol, Quetiapine, Ziprasidone)
• Atomoxetine
• atropine
• azelastine
• belladonna
• Benztropine
• beta-2 agonists (e.g., formoterol, salbutamol, salmeterol)
• beta-blockers (e.g., Carvedilol, Propranolol, Metoprolol, Timolol)
• Captopril
• chloroquine
• Cyclobenzaprine
• Darifenacin
• Dextromethorphan
• Digoxin
• Disopyramide
• dofetilide
• Domperidone
• Doxorubicin
• Dronedarone
• Eliglustat
• Fesoterodine
• Flavoxate
• Flecainide
• glycopyrrolate
• ipratropium
• ketotifen
• Lomitapide
• lopinavir
• macrolide antibiotics (e.g., clarithromycin, erythromycin)
• Maprotiline
• methamphetamine
• Mexiletine
• mifepristone
• Mirtazapine
• nefazodone
• certain opioids (e.g., Codeine, Hydrocodone, Methadone)
• orphenadrine
• Oxybutynin
• procainamide
• Propafenone
• quinidine
• quinine
• quinolone antibiotics (e.g., ciprofloxacin, levofloxacin)
• rifampin
• saquinavir
• scopolamine
• selective serotonin reuptake inhibitors (SSRIs; e.g., Citalopram, Fluoxetine, Paroxetine, Sertraline)
• serotonin antagonists (e.g., , Ondansetron, Granisetron)
• serotonin norepinephrine reuptake inhibitors (SNRIs: e.g., Desvenlafaxine, Duloxetine, Venlafaxine)
• Solifenacin
• tacrolimus
• Tamoxifen
• Tetrabenazine
• tiotropium
• Tolterodine
• Tramadol
• Tranylcypromine
• Trazodone
• tricyclic antidepressants (e.g., Amitriptyline, Clomipramine, Desipramine, Trimipramine)
• tyrosine kinase inhibitors (e.g., Lapatinib, Nilotinib, Sunitinib)
• umeclidinium

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with Myrbetriq (Mirabegron). Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the Nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

Before you begin taking a medication, be sure to inform your doctor of any medical conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should take Myrbetriq (Mirabegron).

Abnormal heart rhythms: Myrbetriq (Mirabegron) can cause abnormal heart rhythms. Certain medications (e.g., Sotalol, quinidine, thioridazine, Chlorpromazine, Pimozide, moxifloxacin, Mefloquine, pentamidine, arsenic trioxide, probucol, Tacrolimus) can increase the risk of a type of abnormal heart rhythm called QT prolongation, and should not be used in combination with Myrbetriq (Mirabegron). You are more at risk for this type of abnormal heart rhythm and its complications if you:

• are female
• are older than 65 years of age
• have a family history of sudden cardiac death
• have a history of heart disease or abnormal heart rhythms
• have a slow heart rate
• have congenital prolongation of the QT interval
• have Diabetes
• have had a stroke
• have low potassium, magnesium, or calcium levels
• have nutritional deficiencies

If you have heart disease and abnormal heart rhythms, or are taking certain medications (e.g., Verapamil, atazanavir), discuss with your doctor how Myrbetriq (Mirabegron) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Myrbetriq (Mirabegron), and whether any special monitoring is needed.

Bladder obstruction: If you have bladder obstruction (blockage) or are taking any other medications, such as anticholinergics, for the treatment of overactive bladder, discuss with your doctor how Myrbetriq (Mirabegron) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Myrbetriq (Mirabegron), and whether any special monitoring is needed.

Glaucoma: If you have glaucoma, discuss with your doctor how Myrbetriq (Mirabegron) may affect your medical condition, and how your medical condition may affect the dosing and effectiveness of Myrbetriq (Mirabegron). Your doctor should perform regular eye exams while you are taking Myrbetriq (Mirabegron).

Heart conditions: Myrbetriq (Mirabegron) may cause increased blood pressure, or an increased heart rate. If you have a history of high blood pressure or heart disease, discuss with your doctor how Myrbetriq (Mirabegron) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Myrbetriq (Mirabegron), and whether any special monitoring is needed.

Kidney function: Kidney Disease or decreased kidney function may cause Myrbetriq (Mirabegron) to build up in the body, causing side effects. If you have reduced kidney function, discuss with your doctor how Myrbetriq (Mirabegron) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Myrbetriq (Mirabegron), and whether any special monitoring is needed.

Liver function: Liver disease or decreased liver function may cause Myrbetriq (Mirabegron) to build up in the body, causing side effects. If you have reduced liver function, discuss with your doctor how Myrbetriq (Mirabegron) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Myrbetriq (Mirabegron), and whether any special monitoring is needed.

Pregnancy: Myrbetriq (Mirabegron) should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking Myrbetriq (Mirabegron), contact your doctor immediately.

Breast-feeding: It is not known if Myrbetriq (Mirabegron) passes into breast milk. If you are a breast-feeding mother and are taking Myrbetriq (Mirabegron), it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using Myrbetriq (Mirabegron) have not been established for children under the age of 18.