Vibegron

Introduction Overview

Generic Name

vibegron

Brand Name

Gemtesa

Dosage Form

tablet 75 mg

Drug Class

Urinary antispasmodics

Pharmacokinetics

Absorption:
Vibegron is administered orally and demonstrates good absorption characteristics, with peak plasma concentrations reached within a few hours post-dose. Although specific human bioavailability data is limited in public sources, the drug exhibits consistent systemic exposure when taken with or without food, indicating food does not significantly affect its absorption. Clinical pharmacology data suggest favorable oral bioavailability supporting once-daily dosing regimens.

Distribution:
Once absorbed, vibegron exhibits a moderate volume of distribution reflecting systemic distribution primarily into the bladder tissues where it exerts its therapeutic effect. Plasma protein binding studies show that vibegron is approximately 60-70% bound to plasma proteins, which helps maintain sustained activity. Tissue distribution studies indicate selective action on beta-3 adrenergic receptors located predominantly on the detrusor muscle.

Metabolism:
Vibegron undergoes minimal hepatic metabolism. It is metabolized mainly via non-CYP450 mediated pathways, with a minor role played by CYP3A4 enzymes according to pharmacokinetic profiling. Due to limited cytochrome P450 metabolism, vibegron has a lower potential for metabolic drug interactions compared to other drugs sharing the CYP pathways.

Elimination:
The elimination half-life of vibegron supports once-daily dosing and is reported to be approximately 25 to 30 hours in healthy adults. Vibegron is primarily eliminated via renal and fecal excretion of unchanged drug and metabolites. Renal clearance accounts for a moderate proportion of total elimination. Dose adjustments may not be necessary in mild to moderate renal impairment based on pharmacokinetic studies, but clinical discretion is advised.

Dosage Forms

Available Dosage Forms:
Vibegron is commercially available as oral tablets containing 75 mg of the active ingredient. The tablets are film-coated, light green in color, and designed for oral administration.

Dosages for Adults and Adolescents:
The recommended dose for adults, including men with concomitant benign prostatic hyperplasia (BPH) treatment, is one 75 mg tablet taken once daily. The dose can be administered with or without food, and tablets can be crushed and mixed with applesauce if swallowing is difficult.

Specific Patient Populations:
While specific pediatric dosing information is not established due to lack of approval for pediatric use, dose adjustment considerations are advised for patients with significant liver or kidney impairment. However, pharmacokinetic data suggest mild to moderate hepatic or renal impairment does not necessitate dose modification. Elderly patients can use the standard dosing regimen without adjustment.

Mechanism Of Action

Vibegron exerts its therapeutic effect through selective activation of beta-3 adrenergic receptors located on the detrusor smooth muscle of the urinary bladder. Beta-3 receptors, when stimulated, lead to relaxation of the detrusor muscle during the bladder filling phase, thereby increasing bladder capacity without interfering with normal voiding function.

At the molecular level, vibegron binds to and activates G protein-coupled beta-3 adrenergic receptors, stimulating adenylate cyclase activity, which in turn elevates intracellular cyclic AMP (cAMP) levels. Elevated cAMP activates protein kinase A, which phosphorylates intracellular targets that reduce intracellular calcium concentrations, leading to muscle relaxation.

This relaxation decreases involuntary detrusor contractions — a key pathological feature in overactive bladder (OAB) symptomatology such as urgency, frequency, and urge incontinence. By increasing bladder capacity and decreasing urinary urgency and frequency, vibegron improves patient quality of life while minimizing anticholinergic side effects common with other OAB therapies.

Compared to other beta-3 agonists such as mirabegron, vibegron shows a highly selective receptor profile, potentially resulting in fewer off-target effects related to beta-1 and beta-2 adrenergic receptors. Clinical trials have demonstrated vibegron's efficacy and safety in reducing OAB symptoms with relatively rapid onset of action and a favorable tolerability profile.

Pharmacological Actions

Selective beta-3 adrenergic receptor agonist.
Relaxation of detrusor smooth muscle of the bladder.
Increases bladder capacity during the urine storage phase.
Reduces urinary urgency, frequency, and incontinence episodes.
Minimal anticholinergic side effects.
Does not induce significant beta-1 or beta-2 adrenergic receptor stimulation.
Improves bladder compliance and reduces involuntary contractions.
Once-daily dosing due to favorable pharmacokinetic profile.
Low potential for drug-drug metabolic interactions.
Therapeutic efficacy in both female and male patients, including those with BPH.

Therapeutic Or Clinical Uses

Treatment of overactive bladder (OAB) symptoms including urinary urgency.
Management of frequent urination associated with OAB.
Reduction of urge urinary incontinence episodes.
Adjunctive therapy for bladder symptoms in men receiving treatment for benign prostatic hyperplasia (BPH).
Alternative treatment option for patients intolerant of anticholinergic OAB therapies.
Use in adult patients requiring once-daily oral therapy for OAB.
Improvement of quality of life related to bladder dysfunction.
Potential off-label use in neurologic bladder dysfunction awaiting further studies.

Side Or Adverse Effects

Nausea
Diarrhea
Headache
Urinary tract infections
Cold symptoms including stuffy nose, sneezing, sore throat
Dry mouth (less common)
Constipation (uncommon, <2%)
Difficulty urinating
Hot flashes
Potential allergic reactions including rash, hives
Rare angioedema with facial or throat swelling
Urinary retention requiring medical attention
Fatigue or dizziness reported rarely
No significant weight gain reported
Generally well tolerated with low incidence of severe adverse effects

Precautions

Assess for history of bladder emptying problems before initiation.
Use cautiously in patients with weak urine stream or urinary retention.
Monitor patients with hepatic or renal impairment closely for tolerance.
Be aware of potential for allergic reactions; discontinue if signs develop.
Not established as safe in pregnancy; weigh risk vs. benefit carefully.
Use with caution in breastfeeding mothers due to limited data.
Patients should inform healthcare provider of all medical conditions prior to therapy.
Patients should be advised to report any new urinary symptoms immediately.
Potential mild gastrointestinal side effects warrant monitoring.
Caution with drugs affecting bladder function or adrenergic system.
Patient adherence and education on once-daily dosing improves outcomes.
Avoid abrupt discontinuation to prevent symptom recurrence.

Warnings

Seek immediate medical attention if signs of allergic reaction occur (hives, breathing difficulties, facial swelling).
Monitor for urinary retention; if inability to void occurs, discontinue therapy and treat appropriately.
Watch for angioedema presenting as swelling of the face, lips, tongue, or throat; discontinue drug immediately if noted.
Not recommended in pediatric patients due to lack of safety data.
Use with caution in patients with severe hepatic or renal dysfunction.
Not indicated for treatment of stress urinary incontinence; do not substitute.
Avoid use in patients with hypersensitivity to vibegron or any tablet components.
Careful observation recommended when used concomitantly with digoxin or other narrow therapeutic index drugs.
Safety in pregnant or breastfeeding women has not been established; use only if clearly needed.
Discontinue if severe adverse reactions or intolerable side effects develop.

Contraindication

Known hypersensitivity to vibegron or any inactive ingredients in the formulation.
Patients with unexplained bladder emptying difficulties or urinary retention may require alternative treatment.
Use contraindicated in patients with severe hepatic impairment until more data is available.
Contraindicated in patients with hypersensitivity reactions including angioedema to beta-3 agonists.
Not approved for pediatric use; contraindicated in this population in absence of safety data.
Caution or contraindication with concurrent use of drugs that may cause urinary retention.
Contraindicated in patients with hypersensitivity to dye components used in the tablet coating.

Drug Interactions

Caution with digoxin or digitalis due to potential for altered serum levels.
Minimal interaction expected with CYP450 substrates due to limited metabolism through these pathways.
Concomitant use with anticholinergic agents may increase risk of urinary retention.
No significant interactions reported with food; can be taken with or without meals.
Potential additive effects when combined with other urinary antispasmodics.
Limited data on interactions with herbal supplements, caution advised.
No clinically meaningful interaction with common cardiovascular medications reported.
Monitor patients on multiple adrenergic agents for blood pressure and heart rate changes.
No significant interaction with commonly used antibiotics or antifungals identified.
Monitor for enhanced adverse effects when combined with drugs causing dry mouth or constipation.

Preparations Of The Drug

Vibegron is formulated as 75 mg oral tablets under the brand name Gemtesa.
Inactive ingredients include croscarmellose sodium, hydroxypropyl cellulose, magnesium stearate, mannitol, and microcrystalline cellulose.
The tablet coating contains FD&C Blue No. 2 aluminum lake, hypromellose, iron oxide yellow, lactose monohydrate, titanium dioxide, and triacetin.
Tablets are light green and film-coated for ease of swallowing.
No generic equivalents are currently available.
Tablets can be administered whole or crushed and mixed with applesauce if swallowing difficulty exists.
Supplied in blister packs or bottles per manufacturer specifications.
Storage recommended at room temperature between 20°C to 25°C (68°F to 77°F).
Manufactured by Urovant Sciences, Inc., a division of Sumitomo Pharma America.
Packaging includes patient information leaflets with dosing and safety instructions.