Can solifenacin cause constipation? Understanding the side effects

October 9, 2025 •

4 min read

In clinical trials for overactive bladder, up to 13.4% of patients on the 10mg dose of solifenacin reported constipation, a significant increase over the placebo group. Yes, can solifenacin cause constipation, and understanding this potential side effect is crucial for patients.

Quick Summary

Solifenacin frequently causes constipation due to its anticholinergic properties, which inhibit muscle contractions in the digestive tract. The risk is dose-dependent. Managing it involves dietary changes, hydration, exercise, and sometimes over-the-counter laxatives.

Key Points

Solifenacin and constipation are linked: Constipation is a common side effect of solifenacin due to its anticholinergic mechanism.
Dose-dependent risk: The risk of experiencing constipation increases with a higher dose of solifenacin.
Mechanism affects gut motility: Solifenacin blocks muscarinic receptors throughout the body, including the digestive tract, which slows down intestinal muscle contractions.
Management is key: Lifestyle changes like increased fiber and hydration are the first line of defense for managing constipation.
Over-the-counter options available: For more persistent cases, osmotic or stimulant laxatives can be used under a doctor's supervision.
When to seek medical advice: Severe or prolonged constipation (over 3 days) or symptoms of a blockage warrant immediate contact with a doctor.

The Mechanism Behind Solifenacin's Constipating Effect

Solifenacin, commonly known by the brand name Vesicare, is an antimuscarinic agent used to treat overactive bladder (OAB). Its primary function is to relax the smooth muscles of the bladder, which helps to reduce urinary urgency, frequency, and incontinence. However, this medication works by blocking muscarinic receptors not only in the bladder but throughout the body, including the gastrointestinal tract.

Acetylcholine is a neurotransmitter that signals muscle contractions, including the peristalsis in the intestines that moves stool through the digestive system. By acting as a competitive muscarinic receptor antagonist, solifenacin interferes with this signaling. This disruption slows down the normal motility of the gastrointestinal tract, leading to delayed gastric emptying and reduced bowel movements, which manifests as constipation.

Clinical Evidence: How Often Does Solifenacin Cause Constipation?

Clinical trials have consistently shown that constipation is one of the most common adverse effects of solifenacin. The risk of developing this side effect is directly related to the dose of the medication. A 12-week randomized, placebo-controlled trial provided clear data on the incidence of constipation at different dosages.

Constipation Rates in Clinical Trials


Adverse Effect	Placebo	Solifenacin 5mg	Solifenacin 10mg
Constipation	2.9%	5.4%	13.4%

As the table illustrates, the percentage of patients experiencing constipation was significantly higher in both the 5mg and 10mg solifenacin groups compared to the placebo group. The data highlights a clear dose-dependent relationship, with the highest incidence occurring at the 10mg dose. This evidence underscores the importance of starting at a lower dose and carefully monitoring for gastrointestinal side effects.

Risk Factors for Constipation with Solifenacin

While anyone taking solifenacin is at risk for constipation, certain factors can increase the likelihood or severity of this side effect. These risk factors include:

Higher Dosage: As demonstrated in clinical trials, taking a higher dose of solifenacin (e.g., 10mg) substantially increases the risk of constipation compared to a lower dose.
Pre-existing GI Conditions: Individuals with existing gastrointestinal issues that cause slowed bowel movement, such as gastroparesis or a history of significant constipation, are at a higher risk. In fact, the medication may be contraindicated in patients with gastric retention or blockage.
Elderly Patients: Older adults are often more sensitive to the anticholinergic effects of medications. Caution is advised for this population, as they are more susceptible to side effects like confusion and constipation.
Dehydration: Insufficient fluid intake can exacerbate constipation, particularly when taking a medication that already slows gut motility. Solifenacin also causes dry mouth, which can be an indicator of general dehydration.
Lack of Physical Activity: A sedentary lifestyle can contribute to constipation. Regular physical activity helps stimulate normal bowel function.

Managing Solifenacin-Induced Constipation

If you experience constipation while taking solifenacin, several lifestyle adjustments and over-the-counter (OTC) options can help alleviate symptoms. It is always important to discuss these strategies with your healthcare provider first.

Lifestyle Modifications

Increase Fiber Intake: Incorporate more high-fiber foods into your diet, such as fruits, vegetables, and whole grains. Fiber adds bulk to stool, helping it pass more easily.
Stay Hydrated: Drink plenty of water throughout the day. Water is essential for softening stool, especially when increasing fiber intake.
Engage in Regular Exercise: Physical activity helps stimulate the muscles in your intestines, promoting more regular bowel movements.
Don't Ignore the Urge: When you feel the urge to have a bowel movement, go promptly. Delaying can make constipation worse over time.
Consider Toileting Position: Using a footstool to elevate your knees can improve your toileting posture and facilitate easier bowel movements.

Over-the-Counter Options

Osmotic Laxatives: Products containing polyethylene glycol (e.g., MiraLAX) work by drawing water into the colon to soften stool. They are generally considered gentle and effective for medication-induced constipation.
Stool Softeners: Medications like docusate sodium (e.g., Colace) help soften the stool by increasing the amount of water and fat it absorbs.
Stimulant Laxatives: For more persistent cases, a mild stimulant laxative like senna may be recommended for short-term use.

Other Common Anticholinergic Side Effects

Constipation is just one of several common anticholinergic side effects associated with solifenacin. Other adverse effects may include:

Dry Mouth: This is the most frequently reported side effect and is also dose-dependent.
Blurred Vision: Solifenacin can affect the eye's ability to focus, causing temporary blurred vision.
Dry Eyes: Reduced tear production can lead to dry and irritated eyes.
Dizziness and Drowsiness: These effects can impair coordination and concentration, especially when first starting the medication.
Heat Stroke: The medication can decrease perspiration, making it harder for the body to cool down in hot weather.

When to Contact Your Doctor

While mild constipation can often be managed with the strategies above, it's crucial to know when to seek medical advice. Contact your doctor immediately if you experience:

Severe abdominal pain
Constipation that lasts for three or more days
Signs of an intestinal blockage, such as severe bloating, pain, or vomiting
Fever, confusion, or hallucinations, which could indicate anticholinergic toxicity

Conclusion

Yes, solifenacin can and often does cause constipation as a direct result of its anticholinergic properties, which slow down intestinal motility. The incidence and severity of this side effect are directly linked to the dose. Patients can proactively manage this issue through lifestyle adjustments such as increased fiber, hydration, and exercise. For more persistent symptoms, various OTC laxatives can provide relief after consulting with a healthcare professional. Understanding the mechanism and available management strategies can help patients effectively navigate this common side effect while benefiting from their overactive bladder treatment. MedlinePlus

Frequently Asked Questions

Solifenacin is an anticholinergic medication that blocks muscarinic receptors in the body, including those in the intestines. This action slows down muscle contractions in the digestive tract, resulting in slower movement of stool and leading to constipation.

The frequency of constipation varies depending on the dosage. In clinical trials, 5.4% of patients on the 5mg dose and 13.4% of patients on the 10mg dose reported constipation, compared to only 2.9% on a placebo.

You can help prevent constipation by increasing your fiber intake through fruits, vegetables, and whole grains, staying well-hydrated, and engaging in regular physical activity. Establishing a consistent bowel routine may also help.

Over-the-counter remedies can include osmotic laxatives like polyethylene glycol (MiraLAX) or stool softeners like docusate sodium. For more severe cases, a short-term stimulant laxative may be used. Always consult your doctor before starting any new medication.

You should contact your doctor if you experience severe abdominal pain or if your constipation lasts for three or more days. These could be signs of a more serious issue.

Yes, studies show that a higher dose of solifenacin is associated with a higher incidence of constipation. Patients on the 10mg dose experienced constipation more frequently than those on the 5mg dose.

Talk to your doctor about drinking grapefruit juice while taking solifenacin, as it can affect how the medication is metabolized. Focusing on a high-fiber diet and plenty of water is the most beneficial approach for managing constipation.