What are the side effects of fesoterodine in the elderly?

Oct 3, 2025 3 min read •

elderly health Pharmacology Overactive Bladder

According to the Mayo Clinic, elderly patients are more susceptible to unwanted side effects from fesoterodine compared to younger adults. Knowing what are the side effects of fesoterodine in the elderly is crucial for safe and effective treatment of overactive bladder (OAB) and related urinary issues. The drug's anticholinergic properties, while effective for OAB, can heighten common issues like dry mouth and constipation, and increase the risk of more serious concerns such as urinary retention and confusion in older, potentially frail patients.

Quick Summary

Fesoterodine's anticholinergic effects can lead to common side effects such as dry mouth and constipation, which are more pronounced in older adults. Key considerations for seniors include a higher risk of urinary retention, potential cognitive effects like confusion, and the need for caution with pre-existing conditions and drug interactions.

Key Points

Increased Anticholinergic Sensitivity: Elderly patients are more susceptible to anticholinergic side effects like dry mouth, constipation, and dizziness due to changes in metabolism and excretion.
Common Side Effects: The most prevalent side effects are dry mouth and constipation, with a higher incidence observed with higher administration amounts, especially in patients 75 years and older.
Risk of Urinary Retention: There is an increased risk of urinary retention, or inability to empty the bladder, particularly for older men with benign prostatic hyperplasia (BPH) or other bladder outlet obstructions.
Potential for Cognitive Effects: Though some studies suggest fesoterodine is less likely to cause cognitive impairment than older anticholinergics, vulnerable patients may still experience confusion, drowsiness, or delirium.
Precautions for Renal and Hepatic Impairment: Patients with severe kidney impairment may need adjustments to administration amounts due to reduced drug clearance, which increases the risk of side effects.
Management and Monitoring: Close monitoring for side effects, adjusting the administration amount based on tolerability, and discussing all medications to avoid drug interactions are crucial for elderly patients.

Fesoterodine's anticholinergic effects in older adults

Fesoterodine, sold under the brand name Toviaz, is an antimuscarinic medication used to treat overactive bladder symptoms. Due to age-related changes in metabolism and excretion, older adults may experience increased concentrations of the active metabolite, 5-hydroxymethyl tolterodine (5-HMT), potentially amplifying anticholinergic side effects.

Common side effects

Anticholinergic effects are responsible for many common side effects, which are more frequent in patients 75 years and older, especially at higher administration amounts.

Dry mouth: The most common side effect, which can be related to the amount administered. Sugarless candy or gum can help stimulate saliva.
Constipation: This occurs due to slowed gastrointestinal motility and is more likely in older adults.
Dry eyes: Reduced tear production can be managed with lubricating eye drops.
Dizziness and headache: These CNS effects may occur, particularly with higher administration amounts, and should be monitored due to the risk of falls.

Comparison of fesoterodine administration amounts in older patients

Studies in older adults show differences in side effects between different administration amounts. The table below summarizes some findings from clinical trials.


Side Effect	Incidence in Placebo Group	Incidence with Fesoterodine (lower amount)	Incidence with Fesoterodine (higher amount)
Dry mouth	7.0%	18.8%	34.6%
Constipation	2.0%	4.2%	6.0%
Dry eyes	0%	1.4%	3.7%
Dizziness*	Not listed	Not listed	Higher (age ≥75)

*While not quantified in the Phase 3 table, dizziness is cited as a higher incidence with higher administration amounts, especially for older patients.

Serious and potentially serious side effects

Some side effects are more serious and require immediate medical attention, with elderly patients facing higher risks due to existing health conditions.

Urinary retention

Fesoterodine can cause the inability to completely empty the bladder. This risk is higher in older adults, especially those with bladder outlet obstruction like BPH. Fesoterodine should not be used in patients with urinary retention.

Cognitive impairment and delirium

Anticholinergics have been linked to confusion and delirium, particularly in vulnerable older adults. Although fesoterodine may have a lower risk due to how it is processed, cases of delirium have been reported, especially with kidney problems. Monitoring for mental status changes is important.

Exacerbation of pre-existing conditions

Use caution with fesoterodine in older adults with:

Glaucoma: Can worsen uncontrolled narrow-angle glaucoma.
Kidney or liver problems: Reduced function can increase drug levels and side effect risk. Adjustments to administration amounts may be necessary for severe renal impairment.
Decreased gastrointestinal motility: Increases the risk of complications like gastric retention.

Overheating

Fesoterodine can reduce sweating, making it harder for the body to cool down. Older adults should take precautions in hot weather to prevent heat stroke.

Management and monitoring for elderly patients

Managing fesoterodine use in older adults requires a personalized approach and close communication with a healthcare provider.

Start with a lower amount, and gradually increase: A lower administration amount is often initiated, increasing based on how well it's tolerated and its effectiveness.
Monitor regularly: Watch for side effects like increased constipation or confusion.
Review medications: Discuss all medications with your doctor to identify potential interactions.
Stay hydrated: Adequate fluid intake helps with dry mouth and constipation.
Consider alternatives: Mirabegron may be an option for those at higher risk of cognitive decline.

Conclusion

Fesoterodine effectively treats overactive bladder, but older adults are more susceptible to anticholinergic side effects. Common issues include dry mouth and constipation, while more serious risks are urinary retention and confusion. A cautious, individualized approach with close monitoring is vital to maximize benefits and minimize harm. For patients with significant health issues like kidney or liver problems or cognitive impairment, the lowest effective administration amount is crucial, and alternative treatments might be considered. Patients and caregivers must promptly report any potential side effects to their medical team.

Sources

Frequently Asked Questions

Elderly patients are more susceptible because of age-related changes in organ function, such as reduced kidney or liver clearance, which can lead to higher concentrations of the medication in the body. They may also have multiple pre-existing health conditions or take other medications that increase the risk of side effects.

To manage dry mouth, try using sugarless candy or gum to stimulate saliva production, or melt small bits of ice in your mouth. If the dryness is severe and lasts for more than two weeks, speak with your doctor or dentist, as persistent dry mouth can increase the risk of dental disease.

Fesoterodine can cause dizziness and blurred vision, which increases the risk of falls in older adults. Patient studies have shown minimal impact on physical functioning or balance, but careful monitoring for these anticholinergic CNS effects is recommended, especially after starting or adjusting the administration amount.

While some studies suggest fesoterodine has a low risk of affecting cognitive function compared to other anticholinergics, central nervous system (CNS) effects like confusion and hallucinations have been reported. Frail elderly patients or those with renal impairment may have a higher risk, and monitoring is important.

Yes, urinary retention is a significant risk, particularly for older adults with bladder outlet obstruction. Fesoterodine is contraindicated in patients with urinary retention, and caution is advised for those with clinically significant bladder outlet obstructions.

The recommended starting administration amount for adults is typically a specific amount once daily, which may be increased based on individual response and tolerability. For patients with severe kidney impairment, the administration amount may need to be limited.

Caution is needed for elderly patients with age-related kidney or liver problems, as these conditions can lead to slower drug clearance and an increased risk of side effects. For severe renal impairment, the administration amount should be limited. Its use is not recommended in severe hepatic impairment.

References

Medical Disclaimer

This content is for informational purposes only and should not replace professional medical advice. Always consult a qualified healthcare provider regarding personal health decisions.