Antimuscarinic Pregnancy: Not recommended during pregnancy — no adequate data in pregnant women; animal reproductive toxicity studies show minor embryotoxicity and fetotoxicity at 6-fold (mice) and 3-fold (rabbits) the maximum recommended human dose by AUC. Breast-feeding is not recommended during treatment.

Fesoterodine

Brand names: Toviaz

Fesoterodine is an antimuscarinic prodrug used to treat the symptoms of overactive bladder, including urgency, frequency and urge incontinence.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 4 mg once daily (recommended starting dose)

Route: Oral (prolonged-release tablet — take with liquid and swallow whole; with or without food)

Frequency: Once daily

Max: 8 mg once daily (maximum daily dose)

§4.2: adults including the elderly — start at 4 mg once daily; based on individual response the dose may be increased to 8 mg once daily, the maximum daily dose being 8 mg. Full treatment effect was observed between 2 and 8 weeks, so efficacy should be re-evaluated after 8 weeks of treatment. In subjects with normal renal and hepatic function receiving a potent CYP3A4 inhibitor the maximum daily dose is 4 mg once daily. Hepatic impairment: mild — 4 mg with cautious increase to 8 mg (4 mg with a moderate CYP3A4 inhibitor; avoid with a potent inhibitor); moderate — 4 mg (avoid with a moderate CYP3A4 inhibitor, contraindicated with a potent inhibitor); severe (Child-Pugh C) — contraindicated. Any dose increase should be preceded by evaluation of individual response and tolerability. Organic causes must be excluded before antimuscarinic treatment; safety and efficacy have not been established in patients with a neurogenic cause for detrusor overactivity. Paediatric: safety and efficacy under 6 years not established (no data), and in children 6 to 17 years no recommendation on a posology can be made (paedDose null).

Dose adjustments

Renal

§4.2 table — mild (GFR 50–80 ml/min) and moderate (GFR 30–50 ml/min) renal impairment: 4 mg with cautious increase to 8 mg; severe (GFR < 30 ml/min): 4 mg. With a moderate CYP3A4 inhibitor: 4 mg in mild/moderate impairment and avoid in severe impairment. With a potent CYP3A4 inhibitor: avoid in mild impairment and contraindicated in moderate or severe impairment.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance or to any of the excipients
Urinary retention
Gastric retention
Uncontrolled narrow angle glaucoma
Myasthenia gravis
Severe hepatic impairment (Child-Pugh C)
Concomitant use of potent CYP3A4 inhibitors in subjects with moderate to severe hepatic or renal impairment
Severe ulcerative colitis
Toxic megacolon

Side effects

Dry mouth (very common — 28.8% vs 8.5% placebo)
Dry eye (common)
Dyspepsia, constipation, abdominal pain, diarrhoea and nausea (common)
Dizziness and headache (common)
Dry throat (common)
Urinary retention including feeling of residual urine, and urinary hesitation (uncommon)

Interactions

Potent CYP3A4 inhibitors — maximum 4 mg once daily in subjects with normal renal and hepatic function; should be avoided in mild renal or mild hepatic impairment; contraindicated in moderate to severe renal or hepatic impairment (§4.2, §4.3)
Moderate CYP3A4 inhibitors — 4 mg in mild/moderate renal or mild hepatic impairment; should be avoided in severe renal or moderate hepatic impairment (§4.2)
Potent CYP3A4 inducers (carbamazepine, rifampicin, phenobarbital, phenytoin, St John's Wort) — concomitant use is not recommended (§4.4)
Potent CYP2D6 inhibitors — caution when prescribing or uptitrating, as increased exposure to the active metabolite is expected (§4.4)
US label §7.1 (cross-check): other antimuscarinic agents — may increase the frequency and/or severity of dry mouth, constipation, urinary retention and other anticholinergic effects

Clinical monograph

How it works

It is rapidly converted to its active metabolite, which antagonises muscarinic receptors on the detrusor muscle to reduce involuntary bladder contractions.

Prescribing in practice

It is contraindicated in urinary retention, gastric retention and uncontrolled narrow-angle glaucoma owing to its antimuscarinic actions.
Dry mouth and constipation are the most frequent adverse effects and can affect adherence.
Dose limitation is advised in significant renal or hepatic impairment and with potent CYP3A4 inhibitors.

Monitoring

Monitor symptomatic response and antimuscarinic side effects, periodically reviewing the need to continue therapy.

Counselling the patient

Swallow the tablet whole and expect symptoms to improve gradually over a few weeks.
Dry mouth and constipation are common; sips of water and dietary fibre may help.
Report inability to pass urine or new eye pain and blurred vision.

Evidence & guidelines

NICE guidance on urinary incontinence supports antimuscarinics such as fesoterodine for overactive bladder where conservative treatment is inadequate.

Reference: NICE NG123; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

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