Gemtesa Side Effects: What to Expect and When to Call Your Doctor

Gemtesa (vibegron) is generally well-tolerated — it has a milder side effect profile compared to many older overactive bladder (OAB) medications. But like all prescription drugs, it can cause side effects. Knowing what to expect, which symptoms are normal, and when to seek medical attention can help you stay on your treatment confidently.

Common Side Effects of Gemtesa

These side effects were reported in ≥2% of patients in Gemtesa's Phase 3 EMPOWUR clinical trial at a rate higher than placebo. They are generally mild and may improve as your body adjusts to the medication:

Headache — The most commonly reported side effect. Usually mild.

Urinary tract infection (UTI) — Reported in clinical trials and in the 52-week extension study (6.6%). If you experience painful urination, frequent small amounts of urine, or cloudy/bloody urine, contact your doctor.

Nasopharyngitis — Nasal congestion, sore throat, or runny nose (cold-like symptoms).

Diarrhea — Typically mild; can often be managed with dietary adjustments.

Nausea — Usually mild and transient.

Upper respiratory tract infection — Bronchitis was reported in 2.9% of patients in the 52-week extension study.

Constipation — Less common (under 2% in the 12-week trial) but reported in longer-term use.

What Gemtesa Does NOT Commonly Cause

One of Gemtesa's key advantages is what it doesn't cause compared to other OAB medications:

No dry mouth or blurred vision — Common problems with anticholinergic OAB drugs like oxybutynin and tolterodine.

No cognitive impairment or memory problems — Gemtesa does not cross the blood-brain barrier. This is especially important for older adults and anyone at risk for dementia.

No blood pressure elevation — A 4-week ambulatory blood pressure study showed no clinically significant blood pressure changes. This is an advantage over mirabegron (Myrbetriq), which can raise BP.

Serious Side Effects: When to Seek Help Immediately

While rare, these serious side effects require immediate medical attention:

Urinary retention — Inability to fully empty your bladder. Symptoms: difficulty urinating, dribbling, or feeling like your bladder is never fully empty. Risk is higher if you have bladder outlet obstruction or are taking other OAB medications (muscarinic antagonists). Call your doctor right away if you experience this. Gemtesa should be discontinued if urinary retention develops.

Angioedema — Rare but potentially life-threatening swelling of the face, lips, tongue, or throat. Can occur after the first dose or after multiple doses. If you experience swelling with difficulty breathing, stop Gemtesa and call 911 immediately.

Post-Market Reported Side Effects

Since Gemtesa's approval in 2020, the following side effects have been reported in real-world use (post-marketing surveillance). These were not identified in clinical trials:

Angioedema of the face and larynx (skin swelling reaction)

Hypersensitivity reactions (urticaria, pruritus, rash, drug eruption, eczema)

Tips for Managing Common Side Effects

Headache: Usually mild and temporary. OTC pain relievers like acetaminophen can help. If persistent, contact your provider.

Nausea/diarrhea: Taking Gemtesa with food may help, though it can also be taken on an empty stomach. Gemtesa's pharmacokinetics are not affected by food.

UTI symptoms: Contact your doctor promptly. Don't self-treat a suspected UTI while on Gemtesa without guidance.

For information about medications that can interact with Gemtesa and change your side effect risk, read Gemtesa Drug Interactions: What to Avoid and What to Tell Your Doctor.