Key takeaways:
Gemtesa (vibegron) is a prescription tablet that treats overactive bladder (OAB) in adults. It’s generally well tolerated by most people who take it.
Mild Gemtesa side effects include headaches, upper respiratory infections and diarrhea. Nausea and dry mouth are also possible. In most cases, you can manage these side effects on your own at home.
It isn’t common, but urinary retention is a serious Gemtesa side effect to be aware of. Let your prescriber know right away if you’re having trouble peeing or emptying your bladder completely.
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Gemtesa (vibegron) is a prescription medication that helps lessen symptoms of overactive bladder (OAB) among adults. It’s an oral tablet that works by relaxing your bladder muscles. This can help reduce sudden urges to pee, along with leaks and accidents.
Gemtesa is well tolerated overall. But, like with any medication, there are side effects to be aware of. Understanding Gemtesa side effects — and how to respond to them — can help you get the most from this OAB treatment.
Gemtesa side effects at a glance
Below are lists of mild and rare but serious Gemtesa side effects. Be sure to talk to your healthcare team about any side effects that appear while you’re taking Gemtesa — even if they aren’t listed below.
Gemtesa side effects that are typically mild include:
Headaches
Urinary tract infections (UTIs)
Diarrhea
Nausea
Constipation
Dry mouth
Hot flashes
Increased blood pressure (more likely among men with benign prostatic hyperplasia)
Rare but potentially serious Gemtesa risks include:
Angioedema (swelling of the face, mouth, or throat)
Urinary retention (trouble peeing)
Let’s dive deeper into seven notable Gemtesa side effects and practical tips for managing them.
1. Headaches
Headaches are a possible Gemtesa side effect. They tend to be mild to moderate in most cases and should improve on their own.
In the meantime, these headache remedies offer relief for many people:
Take an over-the-counter (OTC) pain reliever, such as acetaminophen (Tylenol) or ibuprofen (Advil, Motrin).
Stay hydrated, as dehydration can make headaches worse.
Try stress reduction techniques, such as deep breathing and gentle yoga.
Call your prescriber if your headaches don’t go away or worsen at any point. They can help you figure out the cause(s) of your headaches and if any adjustments to your Gemtesa prescription are necessary.
2. Upper respiratory tract infections
Gemtesa may cause URTIs. Symptoms generally resemble those of the common cold, such as runny nose, sore throat, or mild congestion.
These symptoms are typically mild and should resolve within a few days. To manage these symptoms in the meantime:
Rest as much as possible to help your body to recover.
Stay hydrated.
Take OTC cold medications, such as a decongestant, for symptom relief.
Use a humidifier to further ease congestion and nose or throat irritation.
Tips like these can help make your symptoms more manageable. But make sure to call your prescriber if your cold symptoms extend beyond a few days. They can tell you if another treatment, such as an antiviral or antibiotic, is necessary.
3. Diarrhea
Diarrhea is another possible Gemtesa side effect. This is likely related to how Gemtesa relaxes the bladder and other muscles in the digestive tract.
Persistent diarrhea can lead to significant fluid loss, dehydration, and/or electrolyte imbalances. So priority number one with managing ongoing diarrhea is staying hydrated. Make sure to drink fluids such as water, clear broths, or oral rehydration solutions throughout the day.
Eating bland, easy-to-digest foods — such as bananas, rice, applesauce, and toast — can also help soothe your stomach. Avoid high-fat, spicy, or greasy foods. These can irritate the stomach lining and worsen diarrhea.
OTC antidiarrheals, such as loperamide (Imodium A-D), can help with diarrhea too. But it's best to check with your healthcare team before trying one. They can tell you if they’re safe for you to take.
If your diarrhea worsens at any point, lasts more than a few days, or you also experience symptoms like fever or dizziness, contact your healthcare team right away. A more serious situation may be underway.
4. Nausea
Nausea is another side effect that some people experience while taking Gemtesa. This feeling can range from mild discomfort to intense queasiness. But, again, it’s generally temporary.
If you’re feeling nauseated, strategies to alleviate your symptoms are similar to those used for managing diarrhea:
Eat multiple smaller meals throughout the day rather than three larger meals.
Stick to bland and non-greasy foods that are gentle on the stomach, such as crackers, plain chicken, or rice.
Sip on ginger or peppermint teas that have natural soothing properties.
Avoid foods with strong, off-putting smells or flavors.
Affordable OTC and prescription anti-nausea medicines can help manage nausea too. But it's best to talk to your prescriber before taking one to make sure it’s a safe option for you. Some anti-nausea medications may make certain Gemtesa side effects more likely, such as dry mouth or urinary retention.
5. Dry mouth
Gemtesa may occasionally cause dry mouth. But this side effect tends to be less problematic with Gemtesa compared to other OAB treatments — especially anticholinergics like oxybutynin.
Still, this side effect can be uncomfortable and affect eating, speaking, and oral hygiene. Sipping water regularly during the day is a simple-yet-effective way to moisten your mouth, even if you’re not actively thirsty. Sucking on candies or chewing gum (sugar-free) can help increase saliva production. In more severe cases, OTC saliva substitutes or oral moisturizing gels can provide additional relief.
If dry mouth becomes very bothersome, loop in your prescriber. They might suggest reducing your Gemtesa dosage or switching to an alternative OAB medication, such as Myrbetriq (mirabegron).
6. Hot flashes
Some people have reported hot flashes while taking Gemtesa, but it’s not a common side effect. If it happens, you may have sudden feelings of warmth, sweating, or skin redness.
In most cases, hot flashes should resolve on their own in a short time. Tips to help manage them include:
Wear lightweight and breathable clothing.
Carry a fan or portable ice pack to help you stay cool.
Drink cold fluids to help lower your body temperature.
Practice mindfulness, meditation, or yoga to help lower stress — a common trigger of hot flashes.
Talk to your prescriber if you’re experiencing frequent or intense hot flashes. They might adjust your Gemtesa dosage or explore alternative OAB treatments with you.
7. Urinary retention
Urinary retention is a rare, but serious Gemtesa side effect. This can make it difficult to urinate or creates the sensation that your bladder isn't fully emptying. Urinary retention is more likely if you’re taking Gemtesa along with other medications to manage your OAB symptoms.
It’s crucial to contact your prescriber right away if you have trouble peeing or fully emptying your bladder while taking Gemtesa. Prolonged urinary retention can lead to UTIs or other complications, such as bladder damage or kidney damage, if it isn’t addressed.
Your prescriber will likely have you stop taking Gemtesa prescription and switch you to another OAB medication if you develop urinary retention.
Frequently asked questions
Gemtesa side effects can differ for everyone, so it’s difficult to predict how long they’ll last. Side effects such as headaches, nausea, and URTIs may come and go. But they may also happen less often over time as your body adjusts to the medication. Other side effects, such as dry mouth, may be more persistent.
If at any point Gemtesa side effects become persistent or are interfering with your daily life, let your prescriber know. They can help you figure out the best way to manage them and decide if another OAB treatment may be necessary.
You can take Gemtesa at any time of day, with or without food, as long as you take it at about the same time each day. Many people pick a time they can remember easily, like with breakfast or before bed. Your prescriber may recommend a specific time if you’re waking up at night often to urinate. If you’re unsure what timing works best for your symptoms or with your other medications, check with a pharmacist.
Gemtesa isn’t expected to cause weight gain for most people. In fact, Gemtesa and similar medications are being studied as possible treatments to help with weight loss. Still, everyone’s body responds differently. And weight changes can happen for many reasons — including other medications, your diet, or other health conditions. If you notice unexpected weight changes after starting Gemtesa, talk with your prescriber. They can look for other possible causes and decide whether you need any changes to your OAB treatment plan.
Hair loss didn’t appear as a side effect in Gemtesa’s clinical studies. If you notice new or worsening hair loss or thinning after starting it, another factor is more likely to blame. Hormonal changes, another medication, or even stress could be the cause. Still, let your prescriber know about any unwanted hair changes you experience. They can help identify the cause and recommend potential next steps.
Gemtesa side effects can differ for everyone, so it’s difficult to predict how long they’ll last. Side effects such as headaches, nausea, and URTIs may come and go. But they may also happen less often over time as your body adjusts to the medication. Other side effects, such as dry mouth, may be more persistent.
If at any point Gemtesa side effects become persistent or are interfering with your daily life, let your prescriber know. They can help you figure out the best way to manage them and decide if another OAB treatment may be necessary.
You can take Gemtesa at any time of day, with or without food, as long as you take it at about the same time each day. Many people pick a time they can remember easily, like with breakfast or before bed. Your prescriber may recommend a specific time if you’re waking up at night often to urinate. If you’re unsure what timing works best for your symptoms or with your other medications, check with a pharmacist.
Gemtesa isn’t expected to cause weight gain for most people. In fact, Gemtesa and similar medications are being studied as possible treatments to help with weight loss. Still, everyone’s body responds differently. And weight changes can happen for many reasons — including other medications, your diet, or other health conditions. If you notice unexpected weight changes after starting Gemtesa, talk with your prescriber. They can look for other possible causes and decide whether you need any changes to your OAB treatment plan.
Hair loss didn’t appear as a side effect in Gemtesa’s clinical studies. If you notice new or worsening hair loss or thinning after starting it, another factor is more likely to blame. Hormonal changes, another medication, or even stress could be the cause. Still, let your prescriber know about any unwanted hair changes you experience. They can help identify the cause and recommend potential next steps.
The bottom line
Gemtesa (vibegron) is an oral medication that treats overactive bladder. Most Gemtesa side effects are mild and temporary. Examples include headaches, upper respiratory infections, and nausea. Dry mouth and hot flashes are also possible.
Urinary retention is a rare but serious Gemtesa side effect to be aware of. Contact your prescriber right away if you’re having trouble peeing or fully emptying your bladder. You can also reach out for guidance about any Gemtesa side effects that are persistent or interfering with your daily life.
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References
Cameron, A. P., et al. (2024). The AUA/SUFU guideline on the diagnosis and treatment of idiopathic overactive bladder. Journal of Urology.
Memon, R. J., et al. (2023). Angioedema. StatPearls.
National Institute of Diabetes and Digestive and Kidney Diseases (2019). Definition & facts of urinary retention. National Institutes of Health.
Soliman, S., et al. (2025). Thermogenic targets for obesity management in the era of incretin-based therapies. Pharmaceuticals.
Sumitomo Pharma America. (2025). Gemtesa- vibegron tablet, film coated [package insert].
