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, with the medication demonstrating a favorable safety profile comparable to placebo in clinical trials. 1
Common Adverse Effects (≥2% incidence)
Based on the pivotal 12-week phase 3 trial (Study 3003) in patients with overactive bladder, the following side effects occurred more frequently than placebo 1:
- Headache: 4.0% (vs 2.4% placebo) 1
- Nasopharyngitis: 2.8% (vs 1.7% placebo) 1
- Diarrhea: 2.2% (vs 1.1% placebo) 1
- Nausea: 2.2% (vs 1.1% placebo) 1
- Upper respiratory tract infection: 2.0% (vs 0.7% placebo) 1
In the long-term extension study (52 weeks), additional adverse effects reported in ≥2% of patients included urinary tract infection (6.6%) and bronchitis (2.9%) 1.
Side Effects in Men with BPH
For men with overactive bladder receiving pharmacological therapy for benign prostatic hyperplasia, the 24-week COURAGE trial (Study 3005) showed 1, 2:
The incidence of hypertension was similar between vibegron and placebo groups, indicating no clinically significant cardiovascular risk 2, 3.
Serious Adverse Effects
Urinary Retention
Gemtesa may increase the risk of urinary retention, particularly in patients with bladder outlet obstruction or those taking other overactive bladder medications 1. Patients should be instructed to contact their physician immediately if unable to empty their bladder 1.
Angioedema
Allergic reactions with swelling of the lips, face, tongue, or throat, with or without difficulty breathing, can occur and may be life-threatening 1. This requires immediate discontinuation of Gemtesa and emergency medical attention 1.
Less Common Side Effects (<2% incidence)
Additional adverse reactions reported in less than 2% of patients include 1:
- Dry mouth
- Constipation
- Residual urine volume increased
- Hot flush
Postmarketing Experience
Since approval, additional adverse events reported include 1:
- Urinary retention
- Angioedema of the face and larynx
- Hypersensitivity reactions: urticaria, pruritus, rash, drug eruption
- Eczema
- Constipation
Comparative Safety Profile
Vibegron demonstrates a more favorable tolerability profile compared to antimuscarinics, with significantly lower rates of dry mouth and constipation 4, 3. In the 52-week EMPOWUR extension study, dry mouth occurred in only 1.8% of vibegron patients versus 5.2% with tolterodine 4.
The discontinuation rate due to adverse events was notably low at 2.4% over 52 weeks, compared to 3.3% for tolterodine in the 12-week study 4, 5. This suggests better long-term tolerability 4.
Cardiovascular Safety
Cardiovascular safety studies confirm that vibegron has no clinically significant effects on blood pressure or heart rate 3. The incidence of hypertension with vibegron (1.7% in the pivotal trial) was identical to placebo 5. Long-term data through 52 weeks showed hypertension rates of 8.8% with vibegron versus 8.6% with tolterodine, indicating no increased cardiovascular risk 4.
Drug Interactions
Gemtesa increases digoxin concentrations (Cmax and AUC), requiring serum digoxin monitoring before initiating and during therapy 1. Unlike mirabegron, vibegron's lack of cytochrome P450 interactions offers advantages in patients taking multiple medications 3.
Special Populations
In pregnancy, there are no available data on Gemtesa use in pregnant women 1. Animal studies showed no embryo-fetal developmental toxicity at exposures up to 275-fold (rats) and 285-fold (rabbits) greater than clinical exposure 1. It is unknown if Gemtesa passes into breast milk 1.