Mirabegron (Myrbetriq) - Uses, Dose, Side effects, Brands, MOA

Mirabegron is a medication used to treat certain bladder conditions, primarily overactive bladder (OAB). OAB is a condition characterized by a frequent and sudden urge to urinate, along with urinary incontinence (leakage of urine). Mirabegron is specifically used for people who have not responded well to other treatments for OAB or cannot tolerate other medications commonly used for this condition.

The bladder muscles relax as a result of mirabegron (Myrbetriq) activating the Beta-3 receptors in the bladder.

Mirabegron (Myrbetriq) Uses:

  • Overactive bladder:
    • It can be used alone or in conjunction with solifenacin to treat overactive bladder, which shows up as increased frequency, urgency, or urges incontinence.

Mirabegron Dose in Adults:

Mirabegron Dose in the treatment of Overactive bladder (OAB):

  • Starting Dose: 25 mg taken by mouth once a day. Check how it works after 8 weeks.
  • Adjusting Dose: If needed, you can increase to 50 mg once a day.

Using Mirabegron with Solifenacin:

  • Starting Dose: Take 25 mg of Mirabegron and 5 mg of Solifenacin, both once a day.
  • Adjusting Dose: After 4 to 8 weeks, you can increase Mirabegron to 50 mg once a day if needed.

Use in Children:

The drug's effectiveness and safety in youngsters have not been shown.

Pregnancy Risk Category: C/D

  • Some animal reproduction studies have shown adverse effects associated with Mirabegron.
  • This means that when Mirabegron was tested on animals during pregnancy, there were negative effects observed in the offspring or the pregnancy itself.

Mirabegron use during breastfeeding:

  • Mirabegron might be in breast milk, but we're not sure.
  • The company that makes it says if you're taking it and want to breastfeed, think about the possible risks to the baby, the good parts of breastfeeding for the baby, and the benefits of the medicine for the mom.

Mirabegron Dose in Kidney Disease:

  • If your kidney flow rate is between 30-89 mL/minute: You don't need to change the medicine dose.
  • If it's between 15-29 mL/minute: Don't take more than 25 mg once a day.
  • If it's less than 15 mL/minute: We don't suggest using it because it hasn't been tested.
  • If you're on hemodialysis: We don't suggest using it because it hasn't been tested.

Mirabegron Dose in Liver disease:

  • Mild liver issue (Child-Pugh A): You can take the regular dose.
  • Medium liver issue (Child-Pugh B): Don't take more than 25 mg once a day.
  • Severe liver issue (Child-Pugh C): It's best not to use it, as it hasn't been tested for this.

Side Effects of Mirabegron (Myrbetriq):

  • Cardiovascular:
    • Hypertension
    • Tachycardia
  • Central nervous system:
    • Headache
    • Dizziness
  • Gastrointestinal:
    • Diarrhea
    • Abdominal pain
    • Constipation
    • Xerostomia
  • Infection:
    • Influenza
  • Genitourinary:
    • Urinary tract infection
    • Cystitis
  • Respiratory:
    • Nasopharyngitis
    • Sinusitis
  • Neuromuscular & skeletal:
    • Back pain
    • Arthralgia

Contraindications to Mirabegron (Myrbetriq):

  • Don't use mirabegron if you're allergic to it or anything in it.

For Canadians:

  • Don't use if you have very high blood pressure (above 180/110).
  • Also, don't use if you're pregnant. (This warning isn't on the US label.)

Cautions and alerts


  • Swelling (angioedema) on the face, lips, tongue, or throat has been seen in some people, sometimes after just one dose.
  • This can be very dangerous.
  • If there's swelling on the tongue, lower throat, or voice box, stop taking it right away and get help.

Blood pressure effects:

  • Mirabegron can raise blood pressure, and this effect might get stronger with higher doses.
  • Check your blood pressure regularly if you're taking it.
  • If you have very high blood pressure (above 180/110), it's better not to use it.
  • If your blood pressure is somewhat high but controlled, be careful when using mirabegron and watch your blood pressure closely.
  • Some people with already high blood pressure found it got worse with this medicine.

Bladder flow obstruction

  • If you have problems with bladder flow (like BOO) or are using certain other bladder medicines, be careful with mirabegron.
  • It might increase the risk of not being able to pee properly.

Hepatic impairment

  • If you have mild to medium liver problems, be careful when using mirabegron and you might need a lower dose.
  • If you have severe liver problems, it's better not to use it.

Extension of QT

  • If you have a history of longer heartbeats (QT interval prolongation) or take medicines that can cause this, be careful with mirabegron.
  • One study showed very high doses might affect heartbeats in women but not men.
  • But at normal doses, mirabegron has a low chance of causing longer heartbeats.

Renal impairment

  • If you have kidney problems, be careful when using mirabegron.
  • If you have severe kidney issues, you might need a lower dose.
  • Don't use it if you have end-stage kidney disease (ESRD).

Mirabegron: Drug Interaction

Note: Drug Interaction Categories:

  • Risk Factor C: Monitor When Using Combination
  • Risk Factor D: Consider Treatment Modification
  • Risk Factor X: Avoid Concomitant Use

Risk Factor C (Monitor therapy)


Ajmaline's serum levels may rise after using CYP2D6 Inhibitors (Moderate). 


The serum levels of amphetamines may rise in response to CYP2D6 Inhibitors (Moderate). 

Anticholinergic Agents

might make Mirabegron's harmful or hazardous effects worse. 


The blood concentration of ARIPiprazole may rise in response to moderately potent CYP2D6 inhibitors. Management: Keep an eye out for enhanced pharmacologic effects of aripiprazole. Depending on the concurrent therapy and/or the indication, aripiprazole dosage modifications may or may not be necessary. For detailed advice, refer to the whole interaction monograph. 


Brexpiprazole's serum levels may rise in the presence of moderate CYP2D6 inhibitors. Treatment: The dose of brexpiprazole should be halved if it is to be used with a strong or moderate CYP3A4 inhibitor and both a moderate or strong CYP2D6 inhibitor.


The blood levels of CloZAPine may rise after using CYP2D6 Inhibitors (Moderate). 


The therapeutic benefit of codeine may be diminished by moderate CYP2D6 inhibitors. These CYP2D6 inhibitors could stop codeine from being metabolically converted to its active metabolite, morphine. 

CYP2D6 Substrates (High risk with Inhibitors)

The metabolism of CYP2D6 Substrates may be decreased by moderate CYP2D6 Inhibitors (High risk with Inhibitors). Tamoxifen is an exception. 


Desipramine's serum levels may rise in response to mirabegron. 


The active metabolite(s) of fesoterodine may be present at higher blood quantities while using CYP2D6 inhibitors.


Flecainide's serum levels may rise in response to mirabegron. Management: Keep a watchful eye on the clinical outcome of flecainide. A dose change could be required. In individuals using flecainide, the maximum adult mirabegron dose should be limited to 25 mg/day, according to Canadian mirabegron labeling. 


The serum levels of Indoramin may rise after using CYP2D6 Inhibitors (Moderate). 

Ketoconazole (Systemic)

might raise the serum level of mirabegron. 


Metoprolol's ability to lower blood pressure may be decreased by mirabegron. Metoprolol serum levels may rise as a result of mirabegron. 


Nebivolol's serum levels may rise in response to moderate CYP2D6 inhibitors. 


Pitolisant's serum levels may rise in response to CYP2D6 Inhibitors (Moderate).


Propafenone's serum levels may rise in response to mirabegron. Management: Pay close attention to how propafenone is responding clinically. A dose change could be required. In patients using propafenone, the maximum adult mirabegron dose should be limited to 25 mg/day, according to Canadian mirabegron labeling. 


may lower the level of mirabegron in the serum. 


Mirabegron may intensify Solifenacin's negative or hazardous effects. Particularly, there may be an increased risk of acute urine retention. 


Tamsulosin's serum levels may rise in response to moderately potent CYP2D6 inhibitors. 


CYP2D6 Inhibitors (Moderate) may lessen TraMADol's therapeutic impact. The metabolic conversion of tramadol to its active metabolite, which is largely responsible for its opioid-like effects, may be inhibited by these CYP2D6 inhibitors.

Risk Factor D (Consider therapy modification)


The blood level of Digoxin may rise when Mirabegron is used. Management: When starting concurrent mirabegron, take into account utilizing the lowest digoxin dosage possible. Digoxin dosage should be determined by constantly monitoring serum digoxin concentrations. Risk 

DOXOrubicin (Conventional)

The serum levels of DOXOrubicin may rise after using moderate doses of CYP2D6 inhibitors (Conventional). Treatment: Whenever feasible, avoid using mild CYP2D6 inhibitors in patients receiving doxorubicin. Pfizer Inc., a U.S. company, advises against using certain mixtures. Risk 


Eliglustat's serum levels may rise when used with CYP2D6 Inhibitors (Moderate). Management: Lower the daily dose of eliglustat to 84 mg. Eliglustat shouldn't be used in conjunction with a strong or moderate CYP3A4 inhibitor and a moderate or strong CYP2D6 inhibitor. Risk


The quantity of perhexiline in the serum may rise after using CYP2D6 inhibitors. Management: If feasible, look for alternatives to this pairing. If coupled, keep an eye out for toxicities and higher blood concentrations of perhexiline (eg, hypoglycemia, neuropathy, liver dysfunction). There will probably be a need to lower the dose of perhexiline. Risk 


The active metabolite(s) of tamoxifen may be present at lower serum concentrations while using CYP2D6 Inhibitors (Moderate). In particular, CYP2D6 inhibitors may reduce the metabolic production of extremely powerful active metabolites. Management: Whenever feasible, look at options that have less of an inhibitory impact on CYP2D6 activity. Risk

Risk Factor X (Avoid combination)


Thioridazine's serum levels may rise in response to CYP2D6 inhibitors.

Monitoring parameters:

Blood Pressure

  • Check blood pressure at the start.
  • Keep checking it regularly while on the medicine.

Urinary Retention

  • Watch for signs you're having trouble peeing or can't pee at all.

How to administer Mirabegron (Myrbetriq)?

  • Eat before or after; it doesn't matter.
  • Drink it down with water.
  • Don't chew, split, or crush it. Just swallow it whole.

Mode of action of Mirabegron (Myrbetriq):

  • Mirabegron is a medication that works on a part of the bladder called the detrusor smooth muscle.
  • It activates something called beta-3 adrenergic receptors in the bladder.
  • This makes the bladder muscle relax when you're storing urine, so it can hold more.
  • Mirabegron mainly targets the beta-3 receptor, and it's better at it than affecting other beta receptors.
  • Research shows that these beta receptors, especially the beta-3 type, help control the muscle tone in the bladder and support its storage function.

Start Working Time:

  • You'll start seeing its effects in about 8 weeks.
  • It reaches a stable level in your body in about 7 days.

Spread in the Body:

  • After being given directly into the veins, it spreads out to a volume of about 1670 liters.

Binding in Blood:

  • About 71% of the drug attaches to proteins in the blood. It mainly binds to albumin and a type of protein called alpha-acid glycoprotein.

How the Body Changes It:

  • The body breaks it down a lot using different processes and enzymes like UGT, CYP3A4, and CYP2D6. The main breakdown products don't really affect the body.

How Much Gets Into the Body:

  • If you take a 25 mg pill, 29-35% of the drug will get into your bloodstream. This number changes depending on the dose.
  • Women tend to have higher levels of the drug in their blood than men.

How Long It Stays in the Body:

  • It takes about 50 hours for half of the drug to leave your body.

Highest Level in Blood:

  • The drug reaches its highest level in the blood about 3.5 hours after you take it.

How It Leaves the Body:

  • About 55% leaves through urine, and 34% leaves through feces. Only a small portion of what's in the urine is unchanged drug. None of the drug in the feces is unchanged.

International Brands of Mirabegron:

  • Myrbetriq
  • Betanis
  • Betmiga
  • Betmiga PR
  • Globetric
  • Mirabeg
  • Mirablad
  • Myrbetric

Mirabegron Brand Names in Pakistan:

  • Mrabet 25 mg and 50 mg - CCL Pharma
  • Mibega 25 mg and 50 mg - Getz Pharma


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