TOLTERODINE
Clinical safety rating: safe
Animal studies have demonstrated safety
Competitive antagonist of muscarinic acetylcholine receptors (M1, M2, M3, M4, M5), with selectivity for the M3 receptor subtype involved in detrusor muscle contraction, reducing bladder smooth muscle contractility and increasing bladder capacity.
| Metabolism | Extensively metabolized in the liver via cytochrome P450 2D6 (CYP2D6) to its active metabolite 5-hydroxymethyl tolterodine; also metabolized via CYP3A4 to a lesser extent. Further metabolism via dealkylation and conjugation. |
| Excretion | Primarily hepatic metabolism via CYP2D6 and CYP3A4; renal excretion accounts for <5% of unchanged drug; ~80% excreted in urine as metabolites, ~20% in feces. |
| Half-life | Terminal elimination half-life is 2-4 hours in extensive CYP2D6 metabolizers; increased to 4-10 hours in poor metabolizers or with CYP3A4 inhibitors. |
| Protein binding | Plasma protein binding is >96% (primarily alpha-1-acid glycoprotein and albumin). |
| Volume of Distribution | Vd is approximately 1.0-1.3 L/kg, indicating extensive tissue distribution. |
| Bioavailability | Oral bioavailability is 10-30% due to extensive first-pass metabolism; Extended-release formulation has lower peak concentrations but similar overall exposure. |
| Onset of Action | Immediate-release: 30-60 minutes; Extended-release: 2-4 hours. |
| Duration of Action | Immediate-release: 5-6 hours; Extended-release: 12-24 hours, allowing once-daily dosing. |
| Molecular Weight | 475.62 |
2 mg PO twice daily; may reduce to 1 mg twice daily if tolerated.
| Dosage form | TABLET |
| Renal impairment | For GFR < 30 mL/min: 2 mg PO once daily or 1 mg twice daily. |
| Liver impairment | Child-Pugh Class B or C: 1 mg PO twice daily; avoid use in severe impairment. |
| Pediatric use | Not approved; safety and efficacy not established in pediatric patients. |
| Geriatric use | No specific dose adjustment; start at 2 mg once daily in frail elderly. |
| 1st trimester | Limited data; avoid unless benefit outweighs risk. Animal studies show fetal harm at high doses. |
| 2nd trimester | Limited data; avoid unless benefit outweighs risk. |
| 3rd trimester | Limited data; avoid unless benefit outweighs risk. May cause anticholinergic effects in neonate. |
Clinical note
Strong CYP3A4 inhibitors may increase levels Can cause blurred vision and urinary retention.
| Placental transfer | Yes, based on molecular weight and animal studies; extent not quantified in humans. |
| Breastfeeding | Small amounts excreted in breast milk; monitor infant for anticholinergic effects (e.g., constipation, dry mouth, irritability). Use with caution. |
| Lactation Rating |
■ FDA Black Box Warning
None
| Common Effects | Dry mouth |
| Serious Effects |
Urinary retentionGastric retentionUncontrolled narrow-angle glaucomaHypersensitivity to tolterodine or any component
| Precautions | May cause urinary retention, particularly in patients with bladder outflow obstruction; may cause decreased gastrointestinal motility (use caution in patients with severe constipation, ulcerative colitis, myasthenia gravis); may cause angioedema; may cause CNS effects (e.g., dizziness, somnolence) and worsen cognitive impairment; caution in patients with hepatic impairment (dose reduction for moderate impairment); caution in patients with renal impairment; may exacerbate narrow-angle glaucoma; avoid use in patients with known hypersensitivity. |
| Food/Dietary | No significant food interactions. Grapefruit juice may increase tolterodine exposure via CYP3A4 inhibition; avoid excessive consumption. Alcohol may enhance sedative effects; limit intake. |
Loading safety data…
| L3 (Moderately Safe) |
| Teratogenic Risk | Pregnancy Category C. First trimester: No adequate human studies; animal studies show fetal resorption and skeletal abnormalities at high doses. Second and third trimesters: Potential risk due to anticholinergic effects; use only if benefit outweighs risk. |
| Fetal Monitoring | Monitor maternal heart rate, blood pressure, and urinary function for anticholinergic effects. Fetal should be monitored for tachycardia and decreased amniotic fluid if used long term. |
| Fertility Effects | In animal studies, no significant impact on fertility observed. No human data on reproductive capacity. |
| Clinical Pearls | Tolterodine is a competitive muscarinic receptor antagonist indicated for overactive bladder. It is less lipophilic than oxybutynin, resulting in reduced central nervous system side effects. Dose adjustment required in hepatic impairment (Child-Pugh class A or B) and renal impairment (CrCl <30 mL/min). Avoid use in patients with uncontrolled narrow-angle glaucoma, urinary retention, or gastric retention. CYP2D6 poor metabolizers may have higher exposure; consider dose reduction if poor metabolizer status known or when used with strong CYP2D6 inhibitors like fluoxetine or paroxetine. |
| Patient Advice | Take exactly as prescribed, usually twice daily with or without food. · May cause dry mouth, constipation, blurred vision, or drowsiness; avoid driving if affected. · Avoid alcohol and other CNS depressants as they may increase drowsiness. · Drink plenty of fluids unless otherwise instructed by your doctor. · Do not crush or chew extended-release capsules (if using ER formulation); swallow whole. · Wear sunscreen; tolterodine may increase sensitivity to sunlight. · Seek medical help if you experience severe abdominal pain, difficulty urinating, or signs of an allergic reaction. |