Myrbetriq

Overactive Bladder in Adults

Myrbetriq is primarily used to treat adults with overactive bladder (OAB). It addresses three main symptoms:

• Urinary urgency: A sudden and strong need to urinate that is difficult to delay.
• Urinary frequency: Needing to urinate many times throughout the day or night.
• Urge incontinence: Accidental leaking of urine that occurs immediately after a strong urge to go.

Bladder Control in Children

This medication is also approved for use in children aged 3 years and older to treat a condition called neurogenic detrusor overactivity (NDO). This is a type of bladder dysfunction caused by nerve damage, which can occur with conditions like spina bifida or spinal cord injuries. In these cases, the medication helps increase the amount of urine the bladder can hold and reduces involuntary bladder contractions.

Treatment Context

Healthcare providers may prescribe Myrbetriq alone or sometimes in combination with other medications to manage overactive bladder symptoms. It is typically used when behavioral therapies, such as bladder training or pelvic floor exercises, have not provided enough relief on their own.

How Myrbetriq Works

Myrbetriq is classified as a beta-3 adrenergic agonist. It works by targeting specific receptors in the bladder muscle to change how the bladder behaves while it is filling with urine.

The bladder is surrounded by a muscle called the detrusor. In a typical cycle, this muscle relaxes to allow the bladder to fill and then contracts when you are ready to urinate. For those with overactive bladder, the detrusor muscle may contract too soon or too often, leading to urgency and frequency.

Myrbetriq helps manage these symptoms in the following ways:

• Relaxes the bladder muscle: The medication activates beta-3 receptors on the detrusor muscle, which signals the muscle to stay relaxed while the bladder is storing urine.
• Increases bladder capacity: Because the muscle is more relaxed, the bladder can physically hold more urine before you feel the need to use the bathroom.
• Reduces sudden urges: By preventing the bladder muscle from contracting prematurely, the medication helps reduce the sudden, uncontrollable urge to urinate and helps decrease the number of daily bathroom trips.

This mechanism is different from other common bladder medications, such as anticholinergics, which work by blocking different nerve signals. By focusing specifically on the relaxation phase of the bladder cycle, Myrbetriq helps the bladder store urine more effectively.

Common Side Effects

Many people using Myrbetriq experience mild side effects. These may include:

• Increased blood pressure
• Headache
• Cold symptoms, such as a sore throat or stuffy nose
• Urinary tract infection (UTI)
• Constipation or diarrhea
• Dizziness
• Fast or irregular heartbeat

Serious Side Effects

While less common, some side effects require immediate medical attention. Contact a healthcare provider if you experience:

• Severe high blood pressure
• Difficulty emptying your bladder or a weak urine stream
• Signs of an allergic reaction, such as hives, rash, or swelling of the face, lips, tongue, or throat

Blood Pressure Increases

Myrbetriq can increase blood pressure. It is not recommended for use in people with severe, uncontrolled high blood pressure. Regular blood pressure monitoring is typically advised while taking this medication, especially for those with a history of hypertension.

Urinary Retention

This medication may increase the risk of being unable to empty the bladder (urinary retention), particularly in individuals with a bladder outlet obstruction or those taking other medications for overactive bladder. Caution is advised for people with these conditions.

Angioedema and Allergic Reactions

Serious allergic reactions, including swelling of the face, lips, tongue, or throat (angioedema), have been reported. This can happen after the first dose or after multiple doses. If swelling occurs, the medication should be stopped immediately and medical help sought.

Kidney and Liver Considerations

The dosage of Myrbetriq may need to be adjusted for individuals with severe kidney disease or moderate liver disease. It is generally not recommended for those with end-stage renal disease or severe liver impairment.

Drug Interactions

Myrbetriq can interact with other medications, potentially increasing their levels in the blood. This is particularly important for drugs processed by a specific liver enzyme (CYP2D6), such as certain heart medications or antidepressants.

Pregnancy

There are no adequate or well-controlled studies regarding the use of Myrbetriq in pregnant women. Because human data is limited, the safety of this medication during pregnancy is not fully established. In animal studies, high doses of the drug were associated with developmental issues in the offspring. Consequently, Myrbetriq should be used during pregnancy only if the potential benefit to the mother justifies the potential risk to the fetus.

Breastfeeding

It is currently unknown whether Myrbetriq passes into human breast milk. However, animal studies have shown that the medication is excreted in the milk of lactating rats. Because many drugs are present in human milk and there is a potential for serious adverse reactions in a nursing infant, healthcare providers typically recommend a careful evaluation. A decision should be made whether to discontinue nursing or discontinue the medication, taking into account the importance of the drug to the mother's health.

Available Forms

Myrbetriq is supplied in two different oral forms:

• Extended-release tablets: These tablets are designed to release the medication slowly throughout the day and should be swallowed whole.
• Extended-release oral suspension: This form is provided as granules that are mixed with water to create a liquid for swallowing.

Both forms are designed to provide a steady release of the medication into the body over time.

FDA Approval Status

Myrbetriq (mirabegron) was initially approved by the U.S. Food and Drug Administration (FDA) in 2012. It is available in two formulations: extended-release tablets and granules for oral suspension.

Approved Indications

The FDA has authorized Myrbetriq for the following specific uses:

• Overactive Bladder (OAB): To treat adults experiencing symptoms of urge urinary incontinence, urgency, and urinary frequency. It can be used as a standalone treatment or in combination with solifenacin succinate.
• Neurogenic Detrusor Overactivity (NDO): To treat pediatric patients aged 3 years and older with NDO, a condition where neurological impairment leads to bladder overactivity.

Regulatory Warnings and Precautions

Myrbetriq does not currently have a boxed warning or a Risk Evaluation and Mitigation Strategy (REMS) program. However, the FDA-approved labeling includes significant warnings regarding the following:

• Increased Blood Pressure: Myrbetriq can cause a dose-related increase in blood pressure. It is not recommended for use in patients with severe, uncontrolled hypertension.
• Urinary Retention: There is a risk of urinary retention in patients with bladder outlet obstruction and in those taking muscarinic antagonist medications for overactive bladder.
• Angioedema: Rare but serious allergic reactions involving swelling of the face, lips, tongue, or throat have been reported.

Factors Influencing Cost

The price you pay for Myrbetriq can be affected by several variables:

• Insurance and Medicare: Many insurance plans and Medicare Part D provide coverage for mirabegron. Your out-of-pocket costs will depend on your plan's specific tier for this medication.
• Generic vs. Brand Name: A generic version of Myrbetriq is available. Generic medications contain the same active ingredients but usually cost significantly less than brand-name versions.
• Pharmacy Selection: Costs can differ between local retail pharmacies and mail-order options.

Ways to Save

There are several resources that may help lower the cost of this medication:

• Manufacturer Coupons: The drug manufacturer may offer savings cards or discount programs for patients with commercial insurance.
• Patient Assistance Programs: Some organizations provide financial help to patients who meet certain income criteria or lack adequate insurance coverage.