Detrusitol (Tolterodine)
Antimuscarinic agent for overactive bladder – film-coated tablets
Quick Facts About Detrusitol
Key Takeaways About Detrusitol
- Treats overactive bladder: Detrusitol reduces urinary urgency, frequency, and urge incontinence by blocking muscarinic receptors in the bladder wall
- Standard dose is 2 mg twice daily: The usual dose is 2 mg twice daily, reduced to 1 mg twice daily if side effects occur or in patients with liver or kidney impairment
- Dry mouth is the most common side effect: Up to 35% of patients experience dry mouth, which often improves over the first weeks of treatment
- Avoid in certain conditions: Do not use if you have urinary retention, uncontrolled narrow-angle glaucoma, myasthenia gravis, or severe gastrointestinal obstruction
- Use caution in the elderly: Anticholinergic effects may impair cognitive function in older adults; lowest effective dose recommended
What Is Detrusitol and What Is It Used For?
Detrusitol (tolterodine) is an antimuscarinic medication prescribed for the treatment of overactive bladder (OAB). It works by blocking muscarinic receptors in the detrusor muscle of the bladder, reducing involuntary contractions that cause urgency, frequent urination, and urge incontinence.
Overactive bladder is a common condition affecting an estimated 12–17% of the adult population worldwide, with prevalence increasing with age. The condition is characterised by a sudden, compelling urge to urinate that is difficult to defer (urgency), often accompanied by increased frequency of urination (typically more than eight times per day) and nocturia (waking at night to urinate). Many patients also experience urge incontinence, which is the involuntary loss of urine associated with urgency.
Tolterodine, the active ingredient in Detrusitol, belongs to the antimuscarinic (anticholinergic) class of drugs. It was specifically developed for the treatment of overactive bladder and was designed to have greater functional selectivity for the bladder over the salivary glands compared to older antimuscarinic agents such as oxybutynin. This selectivity translates into a potentially lower incidence of dry mouth while maintaining efficacy in treating bladder symptoms.
The medication works by competitively blocking muscarinic receptors (primarily M2 and M3 subtypes) on the detrusor smooth muscle of the bladder. During the filling phase of the bladder cycle, the parasympathetic nervous system releases acetylcholine, which can trigger involuntary contractions in patients with OAB. By blocking the muscarinic receptors, tolterodine reduces these unwanted contractions, allowing the bladder to fill more completely before the urge to void occurs. This results in fewer episodes of urgency, reduced voiding frequency, and fewer incontinence episodes.
Detrusitol is available as 1 mg film-coated tablets for immediate-release oral administration. An extended-release formulation (Detrusitol SR or Detrol LA) containing 4 mg tolterodine is also available in some markets, which allows for once-daily dosing and may have a more favourable side-effect profile. Clinical trials have demonstrated that tolterodine significantly reduces the number of micturitions per 24 hours and the number of incontinence episodes compared to placebo.
Detrusitol treats the symptoms of overactive bladder but does not cure the underlying condition. It is typically used as part of a comprehensive treatment plan that may also include bladder training, pelvic floor exercises, fluid management, and lifestyle modifications. Your doctor may also recommend behavioural therapies alongside medication for optimal results.
How does tolterodine differ from other OAB medications?
Tolterodine was one of the first antimuscarinics specifically developed for overactive bladder. Compared to oxybutynin, the first antimuscarinic used for OAB, tolterodine has demonstrated a better tolerability profile, particularly regarding dry mouth. This is because tolterodine has relative functional selectivity for the bladder over the salivary glands, meaning it inhibits bladder contractions at doses that cause less salivary suppression.
Other antimuscarinic agents for OAB include solifenacin (Vesicare), darifenacin (Enablex), fesoterodine (Toviaz), and trospium chloride (Sanctura). Each of these medications has slightly different receptor selectivity profiles and pharmacokinetic properties, which may result in different efficacy and side-effect profiles for individual patients. Additionally, newer non-antimuscarinic medications such as mirabegron (Betmiga/Myrbetriq), a beta-3 adrenergic agonist, offer an alternative mechanism of action for patients who do not tolerate or respond to antimuscarinics.
What Should You Know Before Taking Detrusitol?
Before starting Detrusitol, inform your doctor about all medical conditions, especially urinary retention, glaucoma, myasthenia gravis, severe gastrointestinal disorders, and liver or kidney impairment. Tolterodine interacts with several medications, particularly strong CYP3A4 inhibitors and other anticholinergic drugs.
Before prescribing Detrusitol, your healthcare provider needs a comprehensive understanding of your medical history, current medications, and overall health status. Certain conditions make Detrusitol inappropriate or require dose adjustments and careful monitoring. It is essential that you provide complete and accurate information to your doctor to ensure safe and effective treatment.
Contraindications
Detrusitol must not be used in patients with the following conditions:
- Urinary retention: Tolterodine relaxes the bladder muscle, which can worsen difficulty in emptying the bladder completely. If you have significant post-void residual urine volume or a history of urinary retention, Detrusitol may exacerbate this condition.
- Uncontrolled narrow-angle glaucoma: Antimuscarinic drugs can increase intraocular pressure by causing pupil dilation and blocking the drainage of aqueous humour. This can be dangerous in patients with narrow-angle (angle-closure) glaucoma that is not adequately controlled.
- Myasthenia gravis: This autoimmune neuromuscular disorder depends on acetylcholine signalling at the neuromuscular junction. Blocking muscarinic receptors could potentially worsen muscle weakness in affected patients.
- Severe ulcerative colitis: Anticholinergic effects can reduce gastrointestinal motility and potentially worsen the toxic dilatation of the colon that can complicate severe ulcerative colitis.
- Toxic megacolon: The reduction in colonic motility caused by antimuscarinic agents is dangerous in this life-threatening complication.
- Known hypersensitivity: Do not take Detrusitol if you have a known allergy to tolterodine tartrate or any of the excipients in the formulation.
You have uncontrolled narrow-angle glaucoma, urinary retention, myasthenia gravis, severe ulcerative colitis, or toxic megacolon. Contact your doctor immediately if you experience inability to urinate, severe abdominal pain, or sudden eye pain with redness and blurred vision while taking this medication.
Warnings and Precautions
Special care should be taken and dose adjustments may be necessary in patients with:
- Hepatic impairment: Tolterodine is extensively metabolised in the liver, primarily via the cytochrome P450 enzyme CYP2D6. In patients with significantly reduced liver function (Child-Pugh class B or C), the recommended dose should not exceed 1 mg twice daily due to increased plasma concentrations of the drug.
- Renal impairment: In patients with severe renal impairment (creatinine clearance below 30 mL/min), the recommended dose should not exceed 1 mg twice daily as reduced renal clearance leads to higher drug exposure.
- Gastrointestinal obstructive disorders: Antimuscarinic agents reduce gastrointestinal motility and should be used cautiously in patients with conditions such as pyloric stenosis or intestinal atony.
- Bladder outflow obstruction: Patients with conditions such as benign prostatic hyperplasia (BPH) should be carefully assessed before starting treatment, as reduced detrusor contractility may worsen voiding difficulties.
- QT prolongation: Tolterodine has been associated with QT interval prolongation at supratherapeutic doses. Use with caution in patients with known QT prolongation, those taking other medications that prolong the QT interval, or those with electrolyte disturbances (particularly hypokalaemia or hypomagnesaemia).
- Autonomic neuropathy: Patients with autonomic neuropathy may have altered response to antimuscarinic medications.
- Hiatal hernia with gastro-oesophageal reflux: Reduced oesophageal sphincter tone from antimuscarinic effects may worsen reflux symptoms.
Pregnancy and Breastfeeding
There are limited data on the use of tolterodine during pregnancy. Animal studies have not demonstrated teratogenicity, but there is insufficient evidence to confirm safety in human pregnancy. Detrusitol should only be used during pregnancy if the potential benefit justifies the potential risk to the foetus. Women of childbearing potential should discuss contraception with their doctor before starting treatment.
It is not known whether tolterodine is excreted in human breast milk. In animal studies, tolterodine and its metabolites were found in the milk of lactating mice. Therefore, breastfeeding is not recommended during treatment with Detrusitol. If the medication is considered essential, the patient should be advised to discontinue breastfeeding.
Effects on driving and operating machinery
Detrusitol may cause blurred vision, dizziness, and drowsiness in some patients. These side effects can impair the ability to drive vehicles or operate machinery. Patients should be advised to assess their individual response to the medication before engaging in activities requiring alertness and clear vision, especially during the initial period of treatment and after dose adjustments.
How Does Detrusitol Interact with Other Drugs?
Detrusitol interacts with strong CYP3A4 and CYP2D6 inhibitors (such as ketoconazole, itraconazole, and erythromycin), other anticholinergic medications, and drugs that prolong the QT interval. These interactions can increase the plasma concentration of tolterodine or enhance its anticholinergic effects.
Tolterodine is primarily metabolised by the cytochrome P450 enzyme CYP2D6, with CYP3A4 serving as an important alternative metabolic pathway, particularly in individuals who are CYP2D6 poor metabolisers (approximately 7% of the Caucasian population). Understanding these metabolic pathways is essential for predicting and managing drug interactions. Concomitant use of potent inhibitors of these enzymes can significantly increase tolterodine exposure and the risk of adverse effects.
Major Interactions
| Interacting Drug | Mechanism | Clinical Effect | Recommendation |
|---|---|---|---|
| Ketoconazole | Potent CYP3A4 inhibitor | Increases tolterodine levels by 2–3 fold | Reduce dose to 1 mg twice daily; avoid in CYP2D6 poor metabolisers |
| Itraconazole | Potent CYP3A4 inhibitor | Significantly increases tolterodine exposure | Reduce dose to 1 mg twice daily; monitor for side effects |
| Erythromycin | Moderate CYP3A4 inhibitor | Increases tolterodine levels; QT prolongation risk | Reduce dose; monitor ECG in high-risk patients |
| Clarithromycin | Potent CYP3A4 inhibitor | Increases tolterodine exposure significantly | Reduce dose to 1 mg twice daily |
| Fluoxetine | Potent CYP2D6 inhibitor | Inhibits primary metabolic pathway of tolterodine | Monitor for increased side effects; consider dose reduction |
| Paroxetine | Potent CYP2D6 inhibitor | Inhibits primary metabolic pathway of tolterodine | Monitor for increased anticholinergic effects |
Minor Interactions
| Interacting Drug/Class | Mechanism | Recommendation |
|---|---|---|
| Other anticholinergics (e.g. antihistamines, tricyclic antidepressants, antipsychotics) | Additive anticholinergic effects | Avoid combinations where possible; monitor for dry mouth, constipation, confusion |
| Metoclopramide, domperidone | Opposing pharmacological effects on GI motility | Reduced efficacy of prokinetic agents; avoid combination |
| Cholinesterase inhibitors (donepezil, rivastigmine) | Opposing pharmacological effects on cholinergic signalling | May reduce efficacy of both drugs; use alternative OAB treatment if possible |
| QT-prolonging drugs (amiodarone, sotalol, certain antipsychotics) | Additive QT prolongation risk | ECG monitoring recommended; correct electrolyte imbalances |
| Warfarin | No significant pharmacokinetic interaction identified | No dose adjustment required; monitor INR as standard practice |
Approximately 7% of the Caucasian population lacks functional CYP2D6 enzyme activity. In these individuals, CYP3A4 becomes the primary metabolic pathway for tolterodine. This means that CYP3A4 inhibitors will have a greater impact on drug levels in poor metabolisers, making dose reduction particularly important in these patients when co-administering CYP3A4 inhibitors.
What Is the Correct Dosage of Detrusitol?
The standard dosage of Detrusitol is 2 mg twice daily for adults. The dose should be reduced to 1 mg twice daily in patients experiencing troublesome side effects, those with hepatic or renal impairment, or those taking potent CYP3A4 inhibitors. Detrusitol is not recommended for children.
The dosage of Detrusitol should be individualised based on the patient's response and tolerability. Treatment should be initiated at the standard dose, and adjustments made according to clinical response and the occurrence of side effects. The tablets should be swallowed whole with a glass of water and can be taken with or without food.
Adults
Standard Adult Dosage
Recommended dose: 2 mg twice daily (morning and evening)
Reduced dose: 1 mg twice daily if side effects are troublesome
Maximum dose: 4 mg per day (2 mg twice daily)
The 1 mg tablet can be used for the reduced-dose regimen. Treatment efficacy should be assessed after 2–3 months. If there is no significant improvement in symptoms, the continued need for treatment should be re-evaluated. Clinical trials have shown that tolterodine 2 mg twice daily is the optimal balance between efficacy and tolerability for most patients.
Children
Paediatric Use
Detrusitol is not recommended for use in children and adolescents under 18 years of age. The safety and efficacy of tolterodine have not been established in the paediatric population. Clinical trials in children with overactive bladder have not demonstrated a statistically significant difference compared to placebo, and the benefit-risk balance does not support use in this age group.
Elderly
Elderly Patients (65 years and older)
Recommended starting dose: 1 mg twice daily, titrate as tolerated
Elderly patients may be more susceptible to the anticholinergic effects of tolterodine, including cognitive impairment, confusion, hallucinations, and constipation. The American Geriatrics Society Beers Criteria lists antimuscarinics as potentially inappropriate medications for older adults. Treatment should begin at the lowest effective dose with careful monitoring. If tolterodine is poorly tolerated or ineffective, alternative treatments such as mirabegron (a beta-3 adrenergic agonist) should be considered.
Patients with hepatic or renal impairment
Special Population Dosing
Hepatic impairment (Child-Pugh B or C): Maximum 1 mg twice daily
Severe renal impairment (GFR <30 mL/min): Maximum 1 mg twice daily
Concomitant CYP3A4 inhibitors: Maximum 1 mg twice daily
In patients with significantly reduced liver function, the metabolism of tolterodine is impaired, leading to higher plasma concentrations. Similarly, severe renal impairment reduces the clearance of the active metabolite. Both situations require dose reduction to prevent excessive drug accumulation and increased side effects.
| Patient Group | Recommended Dose | Maximum Daily Dose | Notes |
|---|---|---|---|
| Adults (standard) | 2 mg twice daily | 4 mg | Review after 2–3 months |
| Adults (reduced) | 1 mg twice daily | 2 mg | If side effects are troublesome |
| Elderly (≥65 years) | 1 mg twice daily | 4 mg | Start low; monitor cognition |
| Hepatic impairment | 1 mg twice daily | 2 mg | Child-Pugh B/C |
| Severe renal impairment | 1 mg twice daily | 2 mg | GFR <30 mL/min |
| Children (<18 years) | Not recommended | N/A | Safety/efficacy not established |
Missed Dose
If you forget to take a dose of Detrusitol, take it as soon as you remember. However, if it is almost time for your next dose (within a few hours), skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. Missing an occasional dose will not significantly affect the overall treatment, but consistent use is important for optimal symptom control.
Overdose
Overdose with tolterodine may result in severe anticholinergic effects including hallucinations, severe agitation, seizures, respiratory failure, tachycardia, mydriasis (dilated pupils), and urinary retention. In the event of a suspected overdose, seek immediate medical attention. Treatment is primarily supportive and symptomatic. Gastric lavage may be considered if the patient presents within one hour of ingestion. Physostigmine, a cholinesterase inhibitor, may be used as an antidote in severe cases under specialist supervision. Activated charcoal may also reduce absorption if given promptly after ingestion.
If you or someone else has taken more Detrusitol than prescribed, contact your local poison control centre or emergency department immediately. Symptoms of overdose may include confusion, hallucinations, severe drowsiness, rapid heartbeat, difficulty breathing, and seizures. Do not attempt to treat an overdose at home.
What Are the Side Effects of Detrusitol?
The most common side effects of Detrusitol are dry mouth (up to 35%), headache, constipation, dry eyes, and blurred vision. Most side effects are dose-dependent and often improve over the first weeks of treatment. Serious side effects such as urinary retention and angioedema are rare.
Like all medications, Detrusitol can cause side effects, although not everybody gets them. The anticholinergic mechanism of action accounts for most of the adverse effects observed with tolterodine. These effects result from the blocking of muscarinic receptors in various organs and tissues beyond the bladder, including the salivary glands, gastrointestinal tract, eyes, and central nervous system.
Side effects are classified below according to their frequency of occurrence, based on data from clinical trials and post-marketing surveillance. If you experience any side effects that are persistent, severe, or concerning, consult your healthcare provider. Some side effects may require dose reduction, while others may necessitate discontinuation of the medication.
Very Common (affects more than 1 in 10 people)
Frequency: >10%
- Dry mouth – The most frequently reported side effect, occurring in up to 35% of patients. It results from muscarinic receptor blockade in salivary glands. Sugar-free sweets, frequent sips of water, and saliva substitutes can help manage this symptom.
- Headache – Commonly reported, particularly during the first weeks of treatment, and often resolves spontaneously.
Common (affects 1 to 10 in 100 people)
Frequency: 1–10%
- Constipation – Reduced gastrointestinal motility from anticholinergic effects; increase fibre and fluid intake
- Dry eyes – Reduced tear production; artificial tears may be helpful
- Blurred vision – Due to reduced accommodation; usually transient
- Dizziness – More common in elderly patients
- Abdominal pain – Usually mild and self-limiting
- Dyspepsia – Indigestion or stomach discomfort
- Fatigue – May affect ability to concentrate
- Somnolence – Drowsiness, particularly when starting treatment
Uncommon (affects 1 to 10 in 1,000 people)
Frequency: 0.1–1%
- Urinary retention – Difficulty emptying the bladder completely; seek medical attention
- Tachycardia – Increased heart rate
- Palpitations – Sensation of rapid or irregular heartbeat
- Peripheral oedema – Swelling of ankles or feet
- Nervousness – Feeling of anxiety or restlessness
- Paraesthesia – Tingling or numbness
Rare (affects fewer than 1 in 1,000 people)
Frequency: <0.1%
- Angioedema – Severe allergic swelling; seek immediate medical attention
- Anaphylaxis – Life-threatening allergic reaction; call emergency services
- Confusion and hallucinations – Particularly in elderly patients; discontinue and seek medical advice
- Memory impairment – Cognitive effects, more common in older adults
- Worsening of dementia – In patients with pre-existing cognitive decline
Contact your doctor immediately if you experience: inability to urinate, signs of severe allergic reaction (swelling of the face, lips, tongue, or throat; difficulty breathing; rash or hives), severe confusion or hallucinations, chest pain, or significant vision changes. These symptoms may require urgent medical evaluation and possible discontinuation of the medication.
Anticholinergic burden in older adults
An important consideration with Detrusitol, particularly in elderly patients, is the concept of anticholinergic burden. Many commonly prescribed medications have anticholinergic properties, including certain antihistamines, antidepressants, antipsychotics, and gastrointestinal medications. When multiple anticholinergic drugs are taken together, their effects accumulate, leading to a higher overall anticholinergic burden. This cumulative effect has been associated with increased risk of cognitive decline, dementia, falls, hospitalisation, and mortality in older adults.
Healthcare providers should conduct a thorough medication review before prescribing Detrusitol to elderly patients, using tools such as the Anticholinergic Cognitive Burden (ACB) scale to assess total anticholinergic load. Where possible, non-anticholinergic alternatives should be considered, and the lowest effective dose should always be used.
How Should You Store Detrusitol?
Store Detrusitol at room temperature below 25°C (77°F), in the original packaging, protected from moisture. Keep out of the reach and sight of children. Do not use after the expiry date printed on the packaging.
Proper storage of Detrusitol is important to maintain the medication's effectiveness and safety throughout its shelf life. Film-coated tablets should be stored in a dry place at controlled room temperature, not exceeding 25°C (77°F). Avoid storing the medication in bathrooms or near sinks, as the humidity can degrade the film coating and affect the tablet's stability.
Keep the tablets in their original blister packaging until you are ready to take them. This protects them from exposure to light and moisture, both of which can reduce the potency of the active ingredient over time. Do not transfer the tablets to a different container unless it provides equivalent protection.
Always check the expiry date before taking any medication. Do not use Detrusitol after the expiry date stated on the carton and blister pack. The expiry date refers to the last day of that month. Expired medications should not be flushed down the toilet or disposed of in household waste. Return any unused or expired medication to your pharmacist for proper disposal in accordance with local regulations.
What Does Detrusitol Contain?
Each Detrusitol 1 mg film-coated tablet contains 1 mg of tolterodine tartrate (equivalent to 0.68 mg tolterodine base) as the active ingredient, along with several inactive excipients that contribute to the tablet's structure, coating, and stability.
Active ingredient
Tolterodine tartrate 1 mg – Tolterodine is a competitive muscarinic receptor antagonist. The tartrate salt form was selected for its favourable pharmaceutical properties, including good aqueous solubility and stability. The molecular formula of tolterodine tartrate is (C22H31NO)2·C4H6O6, and it has a molecular weight of 475.6 g/mol.
Inactive ingredients (excipients)
The film-coated tablet contains the following excipients:
- Tablet core: Microcrystalline cellulose, calcium hydrogen phosphate dihydrate, sodium starch glycolate, magnesium stearate, colloidal anhydrous silica
- Film coating: Hypromellose, microcrystalline cellulose, stearic acid, titanium dioxide (E171)
Patients with known hypersensitivity to any of these excipients should not take Detrusitol. If you have specific allergies or intolerances (for example, to certain colouring agents or fillers), discuss the full ingredient list with your pharmacist before starting treatment.
Detrusitol 1 mg film-coated tablets do not typically contain lactose or gluten. However, formulations may vary between manufacturers and markets. Always check the patient information leaflet provided with your specific medication, or consult your pharmacist, if you have lactose intolerance or coeliac disease.
Frequently Asked Questions About Detrusitol
References
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About the Medical Editorial Team
This article has been written and reviewed by the iMedic Medical Editorial Team, comprising licensed physicians specialising in urology, clinical pharmacology, and internal medicine. Our editorial process follows the GRADE evidence framework and all medical claims are supported by peer-reviewed research and international clinical guidelines.
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