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Key takeaways
Gemtesa can cause mild side effects like headache, nausea, diarrhea, or cold-like symptoms.
Serious risks include urinary retention, angioedema, high blood pressure, and severe urinary tract infections (UTIs).
People with severe liver or kidney disease, allergies, or bladder blockages should avoid Gemtesa.
Gemtesa (vibegron) is a brand-name prescription drug used to treat overactive bladder (OAB) symptoms in adults, such as frequent urination and sudden urges to urinate. It’s also approved by the FDA for men with OAB and benign prostatic hyperplasia (BPH). Like other medications, Gemtesa is not without side effects. Although most side effects are mild, some can be serious, and it may be a good idea to be aware of them.
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Common side effects of Gemtesa
While many people who take Gemtesa may experience some side effects during treatment, others might not. Data from a 12-week clinical trial shows specific side effects that occur most often in people taking Gemtesa.
The most common side effects of Gemtesa include:
- Headache
- Nausea
- Diarrhea
- Urinary tract infection
- Upper respiratory tract infection
- Common cold symptoms, such as a stuffy or runny nose and sore throat
Although not common, other potential side effects of Gemtesa include dry mouth, constipation, and hot flashes.
Less th an 2% of people stopped taking Gemtesa because of side effects, meaning most people can take the medication without worrying too much. Still, the severity of these side effects can also vary from person to person.
Serious side effects of Gemtesa
While serious side effects of Gemtesa aren’t common, they can’t be ruled out. In some cases, side effects may require emergency care or a visit with a healthcare provider.
Gemtesa and blood pressure
Clinical studies found that high blood pressure (hypertension) occurred more often in men taking Gemtesa for an overactive bladder than those taking a placebo. About 9% of men taking Gemtesa versus 8.3% taking a placebo experienced hypertension. The blood pressure increases may happen slowly over weeks or months, with many not seeing any immediate symptoms.
It’s important to watch for the following, especially in those with a history of blood pressure problems:
- Headaches that won’t go away
- Dizziness or lightheadedness
- Chest pain or tightness
- Vision changes
Healthcare providers may recommend blood pressure medications or increase the doses of current medications. Regular blood pressure checks may be needed during Gemtesa treatment.
Gemtesa and urinary retention
Urinary retention is one of the most serious risks patients face when taking Gemtesa. This means a person can’t empty their bladder completely or at all. Urinary retention happens more often in people who already have bladder blockages, especially men with enlarged prostates.
Warning signs of urinary retention include:
- Unable to urinate at all
- Weak urine stream
- Feeling like the bladder isn’t empty
- Pain or pressure in the lower belly
People taking other bladder medications alongside Gemtesa may have increased chances of this side effect. The medication often needs to be discontinued in people who experience urinary retention.
Gemtesa and angioedema
Angioedema involves serious, sometimes life-threatening, swelling that can occur around the face, lips, tongue, or throat. This reaction can happen after the first dose or after taking Gemtesa for weeks. Although swelling can start as a minor side effect, it can worsen quickly.
Dangerous symptoms are similar to those of allergic reactions and include:
- Swollen face or lips
- Tongue swelling
- Trouble swallowing
- Difficulty breathing
- Throat tightness
Those who experience swelling of the tongue or throat need immediate medical help. Gemtesa will need to be stopped and never prescribed again to someone who experiences this side effect.
Serious urinary tract infection
Urinary tract infections happened more frequently in people taking Gemtesa during clinical trials. Around 2.5% of patients developed UTIs compared to 2.2% taking a placebo. Although it’s considered a common side effect, some infections can be serious and spread to the kidneys if left untreated (pyelonephritis).
Serious UTI symptoms include a high fever, chills, and severe back or side pain. People with frequent UTIs may face higher risks. Women, especially older women, typically get UTIs more often than men.
How soon do Gemtesa side effects start?
Most people who take Gemtesa for overactive bladder symptoms may start experiencing side effects within the first few days of treatment. Gemtesa begins working after the first dose, so side effects can happen quickly. Others might not experience any side effects for several days or weeks. The timing can vary, and factors like age, other medications, and overall health may affect how soon someone experiences side effects.
How long do Gemtesa side effects last?
Gemtesa’s side effects often improve as the body gets used to the medication. For many people experiencing the most common side effects, that could be anywhere from a few days to several weeks. However, some side effects, especially serious ones, can stick around for longer. For example, UTIs and upper respiratory infections may take longer to go away since they need time to clear up.
What are the long-term side effects of Gemtesa?
Gemtesa received FDA approval relatively recently, so there might not be enough research on Gemtesa’s long-term side effects. Most clinical trials focused on short-term effects over 12 to 52 weeks rather than extended periods. Some people may have higher risks of long-term side effects. These include older adults, people with existing bladder problems, and those taking other bladder medications.
Gemtesa contraindications
Certain people need to avoid taking Gemtesa due to potentially serious side effects. If the following contraindications apply, avoid taking Gemtesa.
People with allergies or hypersensitivity reactions
People who have had an allergic reaction to Gemtesa or any of its ingredients should not take this medication. Allergic reactions can range from mild skin rashes to severe swelling or trouble breathing.
People with severe liver or kidney disease
Those with severe liver or kidney problems aren’t able to process Gemtesa well. Taking Gemtesa with these problems may increase the risk of harmful side effects. Healthcare providers generally recommend avoiding Gemtesa in these cases.
Children under 18
Gemtesa is currently approved for use in adults. It hasn’t been studied in people under 18 and should, therefore, be kept out of the reach of children.
People who are pregnant or breastfeeding may need to use extra caution. There isn’t enough safety data about Gemtesa during pregnancy or breastfeeding. It’s best to get medical advice from a healthcare professional about the potential risks.
Gemtesa warnings
The main warnings of Gemtesa involve urinary retention and angioedema. Those with a history of these problems may need to use Gemtesa with caution or avoid it completely. In addition, those who take more than prescribed may experience an overdose with increased side effects. There are currently no boxed warnings or recalls associated with Gemtesa.
Gemtesa interactions
Gemtesa may interact with certain medications, changing how well the drug works or increasing the risk of side effects. It’s recommended to consult a healthcare provider about all medications being taken, including prescription drugs, over-the-counter (OTC) medications, and herbal supplements.
The main interaction involves Lanoxin (digoxin). Gemtesa can increase digoxin levels in the body, which may lead to heart problems such as abnormal heart rhythms. A healthcare provider will want to check digoxin levels before starting Gemtesa and adjust dosages as needed.
Gemtesa may also interact with antimuscarinic agents like Oxytrol (oxybutynin), Detrol (tolterodine), or Vesicare (solifenacin). Taking Gemtesa with these medications can increase the risk of urinary retention since these drugs can also reduce bladder muscle contractions.
Gemtesa is processed by the CYP3A4 enzyme in the liver. However, no drug interactions have been seen when Gemtesa is taken with common medications that could interrupt this liver process, such as ketoconazole, diltiazem, and rifampin. Still, potential interactions with similar drugs can’t be ruled out.
How to avoid Gemtesa side effects
It might be hard to completely prevent all side effects of Gemtesa. However, there may be ways to reduce the risk of side effects when taking Gemtesa.
Before starting Gemtesa
- Tell your healthcare provider about all medical conditions: People with liver problems, kidney disease, or trouble emptying their bladder may have a higher risk of serious side effects like urinary retention.
- Review all medications with a healthcare provider: Gemtesa can interact with digoxin and other bladder medications, which may increase side effects.
- Mention any allergies or past reactions: Anyone allergic to vibegron or similar medications shouldn’t take Gemtesa.
While taking Gemtesa
- Take the medication as prescribed: Take Gemtesa with a glass of water or crush it and mix it with applesauce. Don’t skip doses or take extra doses, as doing so may affect how well your body handles the drug.
- Stay hydrated throughout the day: Drinking plenty of water may help reduce UTI risks and prevent constipation.
- Monitor for allergic reactions: Watch for swelling of the face, lips, tongue, or throat. These symptoms need immediate medical attention.
- Follow up with your healthcare provider regularly: If side effects start to bother you, your healthcare provider can make adjustments or recommend other treatment options.
How to treat side effects of Gemtesa
Most Gemtesa side effects aren’t difficult to manage at home. If side effects get severe or just don’t improve, it’s best to reach out to a healthcare provider.
For example, call a healthcare provider immediately for serious side effects like urinary retention. Signs include difficulty urinating, stomach pain, or an urgent need to urinate. Emergency care is needed for allergic reactions causing face, lip, or throat swelling. These reactions can make it hard to breathe and may be life-threatening.
- Gemtesa highlights of prescribing information, U.S. Food and Drug Administration (2025)
- International phase III, randomized, double-blind, placebo- and active-controlled study to evaluate the safety and efficacy of vibegron in patients with symptoms of overactive bladder: EMPOWUR, The Journal of Urology (2020)
- Efficacy and safety of vibegron for persistent symptoms of overactive bladder in men being pharmacologically treated for benign prostatic hyperplasia: Results from the Phase 3 randomized controlled COURAGE trial, The Journal of Urology (2024)
- Symptoms and causes of urinary retention, National Institute of Diabetes and Digestive and Kidney Diseases (2019)
- Gemtesa, Sumitomo Pharma (n.d.)
- Vibegron (oral route), Mayo Clinic (2025)
- Vibregon, Drugs and Lactation Database (2025)
- Pharmacokinetics and safety of vibegron 75 mg administered as an intact or crushed tablet in healthy adults, Clinical Pharmacology in Drug Development (2022)