Antimuscarinic (overactive bladder) Pregnancy: Fesoterodine is not recommended during pregnancy — there are no adequate data in pregnant women and animal reproductive toxicity studies show minor embryotoxicity (fetotoxicity in mice and rabbits at maternal exposures 6 and 3 times the maximum recommended human dose). Breast-feeding is not recommended during treatment. Women of childbearing potential should be made aware of the lack of human fertility data.

Fesoterodine fumarate

Brand names: Toviaz

Fesoterodine fumarate is an oral antimuscarinic prodrug used for overactive bladder with urgency, frequency, and urge incontinence. It is converted to its active metabolite, which is shared with tolterodine.

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 starting dose, increased to 8 mg based on individual response

Route: Oral — prolonged-release tablets taken with liquid and swallowed whole; may be administered with or without food

Frequency: Once daily

Max: 8 mg daily. In subjects with normal renal and hepatic function receiving concomitant potent CYP3A4 inhibitors the maximum daily dose is 4 mg once daily

ADULTS INCLUDING ELDERLY: the recommended starting dose is 4 mg once daily; based upon individual response the dose may be increased to 8 mg once daily. The full treatment effect was observed between 2 and 8 weeks, so efficacy should be re-evaluated for the individual patient after 8 weeks of treatment. In populations where the dose may be increased to 8 mg once daily, the dose increase should be preceded by an evaluation of individual response and tolerability. HEPATIC IMPAIRMENT (daily dose, from the SPC table): mild — 4 mg with cautious increase to 8 mg; with a moderate CYP3A4 inhibitor 4 mg; with a potent CYP3A4 inhibitor should be avoided. Moderate — 4 mg; with a moderate CYP3A4 inhibitor should be avoided; with a potent CYP3A4 inhibitor contraindicated. Severe (Child-Pugh C) — contraindicated. CAUTIONS: use with caution in clinically significant bladder outflow obstruction at risk of urinary retention (e.g. clinically significant prostate enlargement due to benign prostatic hyperplasia), gastrointestinal obstructive disorders, gastro-oesophageal reflux or concurrent medicines that can cause or exacerbate oesophagitis, decreased gastrointestinal motility, autonomic neuropathy and controlled narrow-angle glaucoma; also in patients at risk of QT prolongation. Organic causes must be excluded before any antimuscarinic treatment is considered, and safety and efficacy have not been established in patients with a neurogenic cause for detrusor overactivity. Angioedema has been reported, sometimes after the first dose — discontinue and treat promptly if it occurs. EXCIPIENT: the prolonged-release tablets contain lactose. PAEDIATRIC: safety and efficacy in children aged under 6 years have not been established (no data available); in children aged 6 to 17 years safety and efficacy have not been established and no recommendation on a posology can be made. SOURCE NOTE: eMC §4.4 and §4.8 are truncated at the source-fetch limit and no eMC §4.5 interactions section was retrieved; interaction entries below come from eMC §4.2/§4.3/§4.4 and, where tagged, the US prescribing information in the same bundle.

Dose adjustments

Renal

Daily dose from the SPC table — mild renal impairment (GFR 50-80 mL/min): 4 mg with cautious increase to 8 mg; moderate (GFR 30-50 mL/min): 4 mg with cautious increase to 8 mg; severe (GFR below 30 mL/min): 4 mg. With a moderate CYP3A4 inhibitor: 4 mg in mild and moderate impairment, should be avoided in severe impairment. With a potent CYP3A4 inhibitor: should be avoided in mild impairment, contraindicated in moderate and severe impairment. (The US label states 8 mg for CLcr 30-89 mL/min and 4 mg for CLcr below 30 mL/min — the UK SPC table above takes precedence.)

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 — the only very common adverse reaction, occurring in 28.8% of the fesoterodine group versus 8.5% on placebo
Constipation, dyspepsia, abdominal pain, diarrhoea and nausea
Dry eye, dry throat and dry skin
Dizziness, headache and insomnia
Urinary tract infection; dysuria
Urinary retention (uncommon — including feeling of residual urine, micturition disorder, urinary hesitation), more common in men and may occur after long-term treatment; angioedema and urticaria are rare

Interactions

Potent CYP3A4 inhibitors — maximum daily dose 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 moderate hepatic impairment (eMC §4.2/§4.3)
Moderate CYP3A4 inhibitors — caution and dose restriction (4 mg once daily in mild or moderate renal impairment and mild hepatic impairment; should be avoided in severe renal impairment and moderate hepatic impairment) (eMC §4.2)
Potent CYP3A4 inducers (carbamazepine, rifampicin, phenobarbital, phenytoin, St John's Wort) — concomitant use is not recommended (eMC §4.4)
Potent CYP2D6 inhibitors — caution when prescribing or up-titrating, as increased exposure to the active metabolite is expected (eMC §4.4)
Other antimuscarinic agents — may increase the frequency and/or severity of dry mouth, constipation, urinary retention and other anticholinergic effects (US label §7.1)
Medicines known to prolong the QT interval — use fesoterodine with caution, especially in patients also taking potent CYP3A4 inhibitors (eMC §4.4)

Clinical monograph

How it works

Its active metabolite competitively antagonises muscarinic receptors on detrusor smooth muscle, reducing involuntary bladder contractions and urgency.

Prescribing in practice

Contraindicated in urinary retention, gastric retention, and uncontrolled narrow-angle glaucoma because antimuscarinic effects can worsen these conditions.
Be mindful of cumulative anticholinergic burden when combined with other antimuscarinic or sedating drugs, particularly in frail older patients.
Dose restriction is needed with potent CYP3A4 inhibitors and in severe renal or hepatic impairment per the SPC.

Monitoring

Review symptomatic response after several weeks and monitor for anticholinergic effects and urinary retention.

Counselling the patient

Dry mouth and constipation are common; adequate fluids and fibre can help.
Seek advice if you cannot pass urine or develop eye pain or blurred vision.
Swallow the prolonged-release tablet whole.

Evidence & guidelines

Licensed for overactive bladder on the basis of randomised trials demonstrating reductions in urgency incontinence episodes versus placebo.

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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