Gemtesa (Vibegron) Side Effects
The most common side effects of Gemtesa include urinary tract infection, headache, nasopharyngitis (nasal congestion/sore throat/runny nose), diarrhea, nausea, and upper respiratory tract infection, occurring in ≥2% of patients. 1
Common Adverse Reactions (≥2% incidence)
Based on the pivotal 12-week phase III trial (Study 3003) with 545 patients:
- Headache: 4.0% (vs 2.4% placebo)
- Nasopharyngitis: 2.8% (vs 1.7% placebo)
- Diarrhea: 2.2% (vs 1.1% placebo)
- Nausea: 2.2% (vs 1.1% placebo)
- Upper respiratory tract infection: 2.0% (vs 0.7% placebo) 1
In the 24-week trial for men with BPH (Study 3005):
- Hypertension: 9.0% (vs 8.3% placebo)
- Urinary tract infection: 2.5% (vs 2.2% placebo) 1
Less Common but Important Side Effects (<2%)
- Dry mouth: 0.32% (notably lower than antimuscarinics)
- Constipation: reported in <2% initially, but 1.14% in some analyses
- Hot flush
- Increased residual urine volume: 1.30% 1, 2
Serious Adverse Reactions (Rare)
Urinary Retention
Gemtesa may increase the risk of urinary retention, particularly in patients with bladder outlet obstruction or those taking other OAB medications. This risk is higher in:
Urinary retention was reported in 0.97% of patients in clinical trials 1. If you cannot empty your bladder, contact your physician immediately.
Angioedema
Life-threatening allergic reactions with swelling of the lips, face, tongue, or throat can occur. Stop Gemtesa immediately and seek emergency care if you experience angioedema or difficulty breathing 1.
Long-Term Safety Data (52 weeks)
In the extension study with 273 patients treated for up to one year, additional adverse reactions included:
- Urinary tract infection: 6.6%
- Bronchitis: 2.9% 1
Real-World Safety Profile
A Japanese postmarketing surveillance study of 1,848 patients found:
- Overall adverse drug reaction rate: 7.63%
- Most common: Increased residual urine volume (1.30%), constipation (1.14%), dysuria (0.97%), urinary retention (0.97%), cystitis (0.65%), dry mouth (0.32%) 2
Cardiovascular Safety
Gemtesa has no clinically significant effects on blood pressure or heart rate. An ambulatory blood pressure monitoring study showed:
- Mean daytime systolic BP difference vs placebo: 0.8 mmHg (not significant)
- Mean 24-hour heart rate difference: 1.0 bpm (not significant)
- Hypertension adverse event rate: 1.7% (same as placebo) 3, 4
This represents a significant advantage over some other OAB medications.
Comparative Tolerability
Gemtesa demonstrates superior tolerability compared to antimuscarinics:
- Discontinuation due to adverse events: 1.7% (vs 1.1% placebo, 3.3% tolterodine)
- Dry mouth incidence substantially lower than antimuscarinics
- No significant anticholinergic side effects 4
Special Populations
Elderly Patients
In patients ≥70 years, Gemtesa showed comparable safety to younger patients, though urinary retention-related events were more common in those ≥65 years 2, 5.
Men with BPH
In men on alpha-blockers for BPH, urinary retention occurred in 0.9% (vs 0.7% placebo), with no clinically meaningful changes in post-void residual volume or urinary flow rates 6.
Key Clinical Pearls
- Most adverse events are mild and transient, occurring early in treatment
- Gastrointestinal side effects (nausea, diarrhea) are generally self-limited
- Monitor for urinary retention in high-risk patients (elderly men, BPH, baseline elevated PVR)
- No routine laboratory monitoring required (unlike antimuscarinics)
- No significant drug-drug interactions via cytochrome P450 (except digoxin requires monitoring) 1