TOLTERODINE TARTRATE
Clinical safety rating: safe
Strong CYP3A4 inhibitors may increase levels Can cause blurred vision and urinary retention.
Competitive antagonist of muscarinic acetylcholine receptors (M1, M2, M3, M4, M5) with relative selectivity for the bladder over salivary glands. Reduces detrusor muscle contractility and bladder pressure.
| Metabolism | Hepatic via CYP2D6 (major) and CYP3A4 (minor); active metabolite 5-hydroxymethyl tolterodine (DD01) is equipotent. Poor metabolizers (CYP2D6 poor metabolizers) have higher exposure via CYP3A4. |
| Excretion | Renal (77%) and fecal (17%): approximately 14% as unchanged tolterodine, 51% as the active 5-hydroxymethyl metabolite, and 12% as other metabolites. Biliary excretion contributes minimally. |
| Half-life | Terminal elimination half-life is 2-3 hours in extensive metabolizers (CYP2D6) and approximately 9 hours in poor metabolizers. In clinical context, dosing interval is adjusted in poor metabolizers (e.g., 2 mg twice daily reduced to 2 mg once daily). |
| Protein binding | Approximately 96.3% bound to plasma proteins, primarily to alpha-1-acid glycoprotein (orosomucoid). |
| Volume of Distribution | 1.4 L/kg (range 1.0-1.9 L/kg), indicating extensive extravascular distribution and moderate tissue penetration. |
| Bioavailability | Oral: absolute bioavailability of tolterodine is approximately 17% in extensive metabolizers due to extensive first-pass metabolism. In poor metabolizers, bioavailability is higher (up to 65%) due to reduced CYP2D6 activity. |
| Onset of Action | Oral: clinical effect (reduction in urinary frequency) typically observed within 1-2 hours after administration. |
| Duration of Action | Oral: lasts approximately 8-12 hours, supporting twice-daily dosing. Clinical effect may persist longer in poor metabolizers due to prolonged exposure. |
| Molecular Weight | 475.6 |
2 mg orally twice daily. May be reduced to 1 mg orally twice daily based on tolerability.
| Dosage form | CAPSULE, EXTENDED RELEASE |
| Renal impairment | For GFR 30-80 mL/min: no adjustment. For GFR <30 mL/min: 1 mg orally twice daily. |
| Liver impairment | Child-Pugh class A or B: 1 mg orally twice daily. Child-Pugh class C: not recommended. |
| Pediatric use | Not approved for use in pediatric patients (safety and efficacy not established). |
| Geriatric use | Consider starting at 1 mg orally twice daily due to increased sensitivity; titrate based on response and tolerability. |
| 1st trimester | Limited human data; animal studies show no teratogenicity at high doses. Use only if benefit outweighs risk. |
| 2nd trimester | Limited human data; no known fetal harm reported. Use with caution. |
| 3rd trimester | Limited human data; potential for anticholinergic effects in neonate (e.g., ileus, respiratory depression). Avoid near term. |
Clinical note
Strong CYP3A4 inhibitors may increase levels Can cause blurred vision and urinary retention.
| FDA category | Animal |
| Placental transfer | Placental transfer is expected due to low molecular weight; however, specific data are lacking. Tolterodine is a lipophilic base with moderate protein binding (96.3%), suggesting limited transfer. |
| Breastfeeding |
■ FDA Black Box Warning
None
| Common Effects | Dry mouth |
| Serious Effects |
Urinary retentionGastric retentionUncontrolled narrow-angle glaucomaHypersensitivity to tolterodine or any component
| Precautions | Urinary retention, Gastric retention, Narrow-angle glaucoma, QT prolongation (dose-related), Hepatic impairment (dose reduction in moderate impairment; not recommended in severe) |
| Food/Dietary | No specific food interactions. Grapefruit juice may increase tolterodine levels via CYP3A4 inhibition; consider avoiding. Take with or without food. |
Loading safety data…
| Excreted into breast milk in small amounts; likely clinically insignificant. Use with caution in neonates due to anticholinergic sensitivity. |
| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | Pregnancy Category C. No adequate and well-controlled studies in pregnant women. In animal studies, tolterodine caused embryo-fetal lethality and decreased fetal weight at doses 20 times the human AUC at the MRHD (4 mg/day). First trimester: Potential risk cannot be ruled out; use only if benefit outweighs risk. Second and third trimesters: Limited data; theoretical risk due to anticholinergic effects on fetal GI motility and heart rate. |
| Fetal Monitoring | Monitor maternal heart rate and blood pressure for anticholinergic effects (tachycardia, hypertension). Assess fetal heart rate and uterine activity if used near term due to potential for fetal tachycardia. Monitor for urinary retention and constipation in mother. |
| Fertility Effects | No human data on fertility. In animal studies, no impairment of fertility was observed in male and female rats at doses up to 2 mg/kg/day (approximately 5 times the human AUC at MRHD). However, anticholinergic effects may theoretically affect reproductive function. |
| Clinical Pearls | Tolterodine tartrate is a competitive muscarinic receptor antagonist used for overactive bladder. It has a higher selectivity for bladder muscarinic receptors over salivary glands, reducing dry mouth compared to oxybutynin. Dose adjustment required in hepatic impairment (Child-Pugh class B or C) and in patients with renal impairment (CrCl <30 mL/min). Avoid use in patients with gastric retention, uncontrolled narrow-angle glaucoma, or myasthenia gravis. Use cautiously in patients with impaired hepatic function, renal impairment, or those taking drugs that inhibit CYP2D6 (e.g., fluoxetine) or CYP3A4 (e.g., clarithromycin). Tolterodine may prolong QT interval; use caution in patients with known QT prolongation or those taking other QT-prolonging drugs. Extended-release formulation offers once-daily dosing with fewer side effects. |
| Patient Advice | Take tolterodine exactly as prescribed; do not increase dose or frequency. · For extended-release capsules, swallow whole; do not crush, chew, or open. · Avoid activities requiring mental alertness until you know how tolterodine affects you; may cause dizziness or blurred vision. · Drink fluids cautiously; tolterodine can reduce sweating and increase risk of heat stroke in hot environments. · Report difficulty urinating, severe constipation, or vision changes to your healthcare provider. · Use with caution in hot weather; stay hydrated and avoid overheating. · Do not drive or operate machinery if experiencing blurred vision or dizziness. · Tell your doctor about all other medications, especially those for heart rhythm, allergies, or depression. |