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Key takeaways
Gemtesa is an oral once-daily overactive bladder treatment considered safe and effective for older adults.
Common side effects of Gemtesa for older adults include headache, cold symptoms, diarrhea, and nausea.
Rare but serious reactions to Gemtesa include angioedema (facial swelling) and urinary retention. Seek urgent medical attention if these develop.
Gemtesa (vibegron) is a prescription medication FDA-approved to treat overactive bladder (OAB) symptoms, such as urinary incontinence and urinary frequency. A beta-3 adrenergic agonist, Gemtesa, works by helping relax the bladder muscle to let it fill more and to not spasm.
Gemtesa is often prescribed to older adults because clinical studies deemed it equally safe and effective in adults 65 and older as the general population. Gemtesa is also specifically approved for OAB in men who are on medication for benign prostatic hyperplasia, or enlarged prostate—a condition that affects older men.
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Common side effects of Gemtesa
There’s no data to suggest that Gemtesa’s side effects in older adults are any different than those experienced by younger adults. Per the drug’s prescribing information, the most common side effects include:
- Headache
- Urinary tract infection (UTI)
- Common cold symptoms (nasopharyngitis)
- Diarrhea
- Nausea
- Upper respiratory tract infection
Headache is the most common adverse reaction, occurring in 22% of Gemtesa users, according to DailyMed. About 15% of clinical trial participants reported cold symptoms like a runny nose and sore throat, and 12% had diarrhea or nausea.
“Compared to other medications for overactive bladder, it’s just as effective — if not more so — with a lower risk of side effects like dry mouth and constipation,” says Allie Buttarazzi, MD, a double board-certified physician and co-owner of Maine Street Medical near Portland, Maine.
Serious side effects of Gemtesa
Two serious side effects that older adults or their caregivers should watch out for are angioedema and urinary retention. Dr. Buttarazzi says angioedema — swelling of the face, lips, or throat — is a rare, life-threatening side effect that “requires immediate medical care.” Urinary retention, or the inability to pee, also requires urgent medical attention, especially if it has progressed to the point of severe distention or lower abdominal pain.
How soon do Gemtesa side effects start?
There is no standardized timeline for when Gemtesa side effects start. An allergic or severe adverse reaction, like angioedema, can appear within 1 to 2 hours of exposure to a new medication. Other common side effects may take weeks to develop.
In general, Gemtesa starts improving symptoms of OAB as soon as two weeks after the first dose, though it may take up to 12 weeks to notice the maximal clinical results. It’s possible for side effects to also develop slowly over the course of days or weeks.
How long do Gemtesa side effects last?
In many cases, drug side effects improve as the body adjusts to a new medication. This can take days or weeks, depending on the person.
If someone experiences a serious adverse reaction, it’s important to know that Gemtesa has a half-life of almost 31 hours. That means it takes more than a day for half of the medication to be eliminated from the body. Any serious side effects should be reported to a healthcare professional immediately, as the patient might need acute care and monitoring for days. It could take several days for Gemtesa to be eliminated from the system after the last dose.
What are the long-term side effects of Gemtesa?
Urinary retention issues are the only long-term side effect of Gemtesa. The risk of urinary retention is higher in people with bladder outlet obstruction (a blockage at the bladder opening) and people who also take muscarinic antagonists such as oxybutynin or tolterodine for OAB.
Anyone who develops urinary retention while taking Gemtesa should seek urgent medical attention and discontinue this medication to avoid long-term bladder or kidney problems. Urinary retention can easily be remedied by a medical professional draining the bladder with a catheter.
Gemtesa interactions
“[Gemtesa] has a very low risk of drug interactions, which is especially helpful since many older adults are on multiple medications,” Dr. Buttarazzi says.
Medications that may interact negatively with Gemtesa include:
- Other overactive bladder medications. Combining Gemtesa with other OAB treatments increases the risk of urinary retention.
- Digoxin (Lanoxin). Combining Gemtesa with this heart medication can cause digoxin to build up in the body instead of being excreted at the usual pace.
It’s important to share a full list of your medications (including over-the-counter drugs and supplements) with your prescriber and pharmacist before starting Gemtesa.
Safety measures while using Gemtesa
Gemtesa is considered generally safe for adults. It has no FDA “black box warnings” or drug recalls for these medications. It is not habit-forming, and there have been no reports of Gemtesa overdose. However, Gemtesa is not approved for pediatric use, and there is insufficient data to determine its safety in pregnant or breastfeeding women.
That said, there are safety measures when considering the potential for Gemtesa side effects in elderly patients. The first? Whether the patient is able to verbally or nonverbally communicate symptoms of urinary retention. “It is necessary for the patient to be able to inform a loved one or doctor if they have not urinated in over 12 hours or are having sudden abdominal pain with the inability to pass urine,” says Troy Alexander-EL, MD, board-certified internal medicine and primary care physician in Portland, Oregon. “I would be cautious of using this medication in those with cognitive conditions such as dementia.”
Dr. Buttarazzi also recommends that older adults or their caregivers monitor for signs of hypertension (high blood pressure) or urinary retention symptoms. She says it’s especially important to pay close attention to signs of urinary retention if the older adult is on other medications known to cause it. These may include other beta-3 adrenergic agonists, certain anticholinergic medications, certain serotonin and norepinephrine reuptake inhibitors (SNRIs), and more. It’s a good idea to ask a healthcare professional for a full list of drugs linked to an increased risk of bladder retention.
How to avoid Gemtesa side effects
Good news: “The risk for side effects is actually much lower with this type of medication compared to others that work on the bladder for urine retention and overactive bladder,” Dr. Alexander-El says.
Here are some steps to further minimize Gemtesa side effects:
- Take Gemtesa at the same time each day. The drug manufacturer, Sumitomo, states that Gemtesa is a once-daily medication that can be taken anytime, with or without food. Pick a time that’s easy to remember, then stay consistent.
- Crush the pill for easier dosing. Gemtesa tablets are formulated to be crushable for older adults who have difficulty swallowing pills. This is especially helpful for Gemtesa users with a sore throat as a side effect.
- Take it with applesauce. When crushed, Gemtesa should be mixed into a tablespoon of applesauce for easier swallowing. Chase it down with a glass of water. This dosing method may also minimize throat soreness.
Gemtesa is often prescribed as a long-term treatment for OAB. Report any complications or new or worsening side effects to a healthcare provider. Discuss problems early to avoid unnecessary side effect complications.
How to treat side effects of Gemtesa
Mild Gemtesa side effects can be treated as the symptoms would be treated in any other case. For instance, headaches may improve with cold compresses, sleep, or over-the-counter (OTC) pain relief medications. Diarrhea can often be managed with good hydration, a bland diet, and, in some cases, OTC medications.
Remember, angioedema and urinary retention should not be treated at home. These side effects are rare but serious. They require urgent medical attention.
Bottom line: Is Gemtesa safe for older adults?
Yes, Gemtesa is considered generally safe for older adults, including men with benign prostatic hyperplasia. Key safety considerations include administering Gemtesa at the same time each day, not combining Gemtesa with other OAB medications, monitoring for angioedema and urinary retention, and reporting any serious reactions to a healthcare provider.
- Highlights of prescribing information: GEMTESA (vibegron) tablets, for oral use, U.S. Food and Drug Administration (2024)
- Successful management of OAB is critical for older adults, Gemtesa
- 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)
- Vibegron improves quality‐of‐life measures in patients with overactive bladder: Patient‐reported outcomes from the EMPOWUR study, International Journal of Clinical Practice (2021)
- Bladder outlet obstruction, MedlinePlus (2024)
- Definition and facts of urinary retention, National Institutes of Diabetes and Digestive and Kidney Diseases (2019)
- Drugs associated with urinary retention adverse reactions: a joint analysis of FDA adverse event reporting system and mendelian randomization, Urology (2024)
- Comparative efficacy and safety of mirabegron and vibegron in female patients with overactive bladder: a systematic review and meta-analysis of randomized controlled trials, Urology (2025)
- Systematic review and meta-analysis of the efficacy and safety of vibegron vs antimuscarinic monotherapy for overactive bladder, Medicine (2021)