Mirabegron is an orally bioavailable agonist of the human beta-3 adrenergic receptor (ADRB3), with muscle relaxing, neuroprotective and potential antineoplastic activities. Upon oral administration, mirabegron binds to and activates ADRB3, which leads to smooth muscle relaxation. Mirabegron also restores sympathetic stimulation in mesenchymal stem cell (MSC) niches, inhibits JAK2-mutated hematopoietic stem cell (HSC) expansion and blocks the progression of myeloproliferative neoplasms (MPNs). Lack of sympathetic stimulation of the MSC and HSC niche is associated with the development of MPNs.
Mirabegron is a beta-3 adrenergic receptor agonist for the management of overactive bladder. It is an alternative to antimuscarinic drugs for this indication. FDA approved on June 28, 2012. Mirabegron activates the β3 adrenergic receptor in the detrusor muscle in the bladder, which leads to muscle relaxation and an increase in bladder capacity.
Mechanism of action of mirabegron
Mirabegron is a potent and selective agonist for beta-3 adrenergic receptors. Once beta-3 receptors are activated, the detrusor smooth muscle relaxes to allow for a larger bladder capacity. At higher doses (200 mg), there is a potential for mirabegron to activate beta-1 and beta-2 adrenergic receptors.
Indications of mirabegron
- Overactive Bladder
- Urinary Incontinence
- urge urinary incontinence, urgency
- urinary frequency.
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Mirabegron is a beta-3 adrenergic agonist indicated for the treatment of overactive bladder (OAB) with symptoms of urge urinary incontinence, urgency, and urinary frequency.
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Symptomatic treatment of urgency, increased micturition frequency and/or urgency incontinence as may occur in adult patients with overactive bladder (OAB) syndrome
Contra-Indications of mirabegron
- Hypersensitivity to the active substance or to any of the excipients listed in section 6.1.
- Severe uncontrolled hypertension defined as systolic blood pressure ≥ 180 mm Hg and/or diastolic blood pressure ≥ 110 mm Hg.
Dosages of mirabegron
- Strengths: 25 mg; 50 mg
Urinary Incontinence
- Initial dose: 25 mg orally once a day
- Maintenance dose: 25 to 50 mg orally once a day based on individual patient efficacy and tolerability
Urinary Frequency
- Initial dose: 25 mg orally once a day
- Maintenance dose: 25 to 50 mg orally once a day based on individual patient efficacy and tolerability
Side effects of mirabegron
The most common
- Dry mouth
- Urinary tract infection
- Headache
- Constipation
- Dizziness
- Joint pain
- Cystitis
- Back pain
- sleepiness
- urinary retention
- chest pain, fast or uneven heart rate;
- confusion, hallucinations;
- urinating less than usual or not at all; or
- painful or difficult urination.
More common
- Abnormal vision, including difficulty with adjusting to distances
- bloody or cloudy urine
- difficult, burning, or painful urination
- frequent urge to urinate
- Sensation of pins and needles in the fingers and toes
- Allergic reactions
- Nervousness
- Aware of the heartbeat (palpitations)
- Heart failure
- Irregular heartbeat
- Heart burn
- Memory impairment
Less common
- Chest pain
- cough
- diarrhea
- fever
- general feeling of discomfort or illness
- headache
- joint pain
- loss of appetite
- muscle aches and pains
- nausea
- pain or tenderness around the eyes and cheekbones
- shortness of breath or troubled breathing
- sore throat
- stuffy or runny nose
- sweating
- tightness of the chest or wheezing
- trouble with sleeping
Drug interactions of Mirabegron
Mirabegron may interact with following drugs,suppliment & may change the efficasy of drugs
- amitriptyline
- amoxapine
- aripiprazole
- betaxolol
- captopril
- carvedilol
- chlorpromazine
- citalopram
- clomipramine
- desipramine
- duloxetine
- fluoxetine
- fluphenazine
- fluvoxamine
- haloperidol
- imipramine
- metoprolol
- mirtazapine
- nortriptyline
- paroxetine
- pindolol
- propranolol
- protriptyline
- risperidone
- sertraline
- tamoxifen
- thioridazine
- timolol
- tolterodine
- tramadol
- trimipramine
Pregnancy & Lactation
FDA Pregnancy Category C
Pregnancy
Mirabegron falls into category C. In animal studies, pregnant animals were given this medication and had some babies born with problems. No well-controlled studies have been done in humans. Therefore, this medication may be used if the potential benefits to the mother outweigh the potential risks to the unborn child.
Lactation
Although mirabegron was found in the milk of rats in animal studies, it is not known if mirabegron is excreted in human milk. As many drugs are excreted into human milk and have the potential of causing harm to nurse infant, mirabegron should only be used during nursing if it is clearly needed.
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