TOVIAZ

Clinical safety rating: caution

Comprehensive clinical and safety monograph for TOVIAZ (TOVIAZ).

How it works

Competitive antagonist of muscarinic acetylcholine receptors (M1-M5), with high selectivity for M3 receptors, reducing detrusor muscle contractions and bladder overactivity.

What the body does with it

Metabolism	Primarily hepatic via CYP2D6 and CYP3A4 to active metabolite (5-hydroxymethyl tolterodine); also undergoes dealkylation and oxidative metabolism.
Excretion	Approximately 18% renal excretion of unchanged drug; major elimination via hepatic metabolism (CYP3A4 and CYP2D6) with subsequent biliary/fecal excretion of metabolites. Fecal excretion accounts for ~60% of total elimination, while urinary excretion is <20% as unchanged fesoterodine or active metabolite.
Half-life	Terminal elimination half-life of the active metabolite (5-hydroxymethyl tolterodine) is approximately 7-8 hours in extensive CYP2D6 metabolizers and 9-10 hours in poor metabolizers. Clinical context: supports twice-daily dosing for sustained antimuscarinic effect.
Protein binding	Approximately 50% bound to plasma proteins (primarily albumin and alpha-1-acid glycoprotein) for the active metabolite; parent fesoterodine is rapidly hydrolyzed and not detectable in systemic circulation.
Volume of Distribution	Volume of distribution at steady state (Vdss) for the active metabolite is approximately 1.1 L/kg (range 0.9-1.3 L/kg), indicating extensive extravascular distribution into tissues, including bladder.
Bioavailability	Fesoterodine is a prodrug with absolute oral bioavailability of approximately 50% for the active metabolite (5-hydroxymethyl tolterodine). Food does not significantly affect bioavailability.
Onset of Action	Oral administration: Onset of anticholinergic effects (e.g., reduction in urinary frequency) observed within 1-2 hours after a single dose; maximum effect may take several days to weeks.
Duration of Action	Duration of pharmacodynamic effect (e.g., increased bladder capacity) lasts approximately 12 hours, consistent with twice-daily dosing. Clinical note: Continuous therapy for overactive bladder; effects maintained with regular dosing.

Classification & Brands

Dosing & administration

4 mg orally once daily; may increase to 8 mg once daily based on individual response and tolerability.

Dosage form	TABLET, EXTENDED RELEASE
Renal impairment	For GFR 30-89 mL/min: no adjustment; for GFR <30 mL/min: maximum dose 4 mg once daily.
Liver impairment	Child-Pugh A: no adjustment; Child-Pugh B: maximum dose 4 mg once daily; Child-Pugh C: not recommended.
Pediatric use	Safety and efficacy not established in pediatric patients.
Geriatric use	No specific dose adjustment; use with caution due to increased risk of anticholinergic effects (e.g., cognitive impairment, falls).

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for TOVIAZ (TOVIAZ).

Breastfeeding	Unknown if fesoterodine (TOVIAZ) is excreted in human milk; M/P ratio not available. Caution in breast-feeding due to potential anticholinergic effects in infant.
Teratogenic Risk	FDA Pregnancy Category C: Animal studies show fetal harm (reduced fetal weight, skeletal abnormalities) at 10-20 times human exposure. No adequate human studies. Avoid use in first trimester; use only if benefit justifies potential risk in second/third trimester.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

No FDA-required black box warnings.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Urinary retention","Gastric retention","Uncontrolled narrow-angle glaucoma","Hypersensitivity to fesoterodine or any component"]

Clinical Precautions

Precautions

["Urinary retention","Gastric retention (e.g., decreased GI motility)","Narrow-angle glaucoma (uncontrolled)","QT prolongation (dose-related, avoid with QT-prolonging drugs or electrolyte disturbances)","Hepatic impairment (avoid in severe impairment)","Renal impairment (dose adjustment in severe impairment)"]

Clinical Tips & Counseling

Drug interactions

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TOVIAZ

Clinical safety rating: caution

Comprehensive clinical and safety monograph for TOVIAZ (TOVIAZ).

How it works

Competitive antagonist of muscarinic acetylcholine receptors (M1-M5), with high selectivity for M3 receptors, reducing detrusor muscle contractions and bladder overactivity.

What the body does with it

Metabolism	Primarily hepatic via CYP2D6 and CYP3A4 to active metabolite (5-hydroxymethyl tolterodine); also undergoes dealkylation and oxidative metabolism.
Excretion	Approximately 18% renal excretion of unchanged drug; major elimination via hepatic metabolism (CYP3A4 and CYP2D6) with subsequent biliary/fecal excretion of metabolites. Fecal excretion accounts for ~60% of total elimination, while urinary excretion is <20% as unchanged fesoterodine or active metabolite.
Half-life	Terminal elimination half-life of the active metabolite (5-hydroxymethyl tolterodine) is approximately 7-8 hours in extensive CYP2D6 metabolizers and 9-10 hours in poor metabolizers. Clinical context: supports twice-daily dosing for sustained antimuscarinic effect.
Protein binding	Approximately 50% bound to plasma proteins (primarily albumin and alpha-1-acid glycoprotein) for the active metabolite; parent fesoterodine is rapidly hydrolyzed and not detectable in systemic circulation.
Volume of Distribution	Volume of distribution at steady state (Vdss) for the active metabolite is approximately 1.1 L/kg (range 0.9-1.3 L/kg), indicating extensive extravascular distribution into tissues, including bladder.
Bioavailability	Fesoterodine is a prodrug with absolute oral bioavailability of approximately 50% for the active metabolite (5-hydroxymethyl tolterodine). Food does not significantly affect bioavailability.
Onset of Action	Oral administration: Onset of anticholinergic effects (e.g., reduction in urinary frequency) observed within 1-2 hours after a single dose; maximum effect may take several days to weeks.
Duration of Action	Duration of pharmacodynamic effect (e.g., increased bladder capacity) lasts approximately 12 hours, consistent with twice-daily dosing. Clinical note: Continuous therapy for overactive bladder; effects maintained with regular dosing.

Classification & Brands

Dosing & administration

4 mg orally once daily; may increase to 8 mg once daily based on individual response and tolerability.

Dosage form	TABLET, EXTENDED RELEASE
Renal impairment	For GFR 30-89 mL/min: no adjustment; for GFR <30 mL/min: maximum dose 4 mg once daily.
Liver impairment	Child-Pugh A: no adjustment; Child-Pugh B: maximum dose 4 mg once daily; Child-Pugh C: not recommended.
Pediatric use	Safety and efficacy not established in pediatric patients.
Geriatric use	No specific dose adjustment; use with caution due to increased risk of anticholinergic effects (e.g., cognitive impairment, falls).

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for TOVIAZ (TOVIAZ).

Breastfeeding	Unknown if fesoterodine (TOVIAZ) is excreted in human milk; M/P ratio not available. Caution in breast-feeding due to potential anticholinergic effects in infant.
Teratogenic Risk	FDA Pregnancy Category C: Animal studies show fetal harm (reduced fetal weight, skeletal abnormalities) at 10-20 times human exposure. No adequate human studies. Avoid use in first trimester; use only if benefit justifies potential risk in second/third trimester.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

No FDA-required black box warnings.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Urinary retention","Gastric retention","Uncontrolled narrow-angle glaucoma","Hypersensitivity to fesoterodine or any component"]