What are the side effects of Tolterodine (Detrol)?

Tolterodine Side Effects

Tolterodine commonly causes dry mouth, constipation, blurred vision, and dizziness, with dry mouth being the most frequent adverse effect occurring in approximately 35% of patients. 1

Common Side Effects

Tolterodine is an antimuscarinic medication used to treat overactive bladder. According to the FDA drug label, the most frequently reported side effects include:

• Dry mouth (35%) - most common side effect
• Constipation (7%)
• Headache (7%)
• Dizziness/vertigo (5%)
• Abdominal pain (5%)
• Dyspepsia (4%)
• Diarrhea (4%)
• Abnormal vision/accommodation problems (2%)
• Fatigue (4%)
• Somnolence (3%)
• Xerophthalmia (dry eyes) (3%) 1

Serious Side Effects

While less common, more serious side effects may include:

• Urinary retention - particularly in patients with bladder outlet obstruction
• Hallucinations - particularly in elderly patients or those taking cholinesterase inhibitors
• Angioedema and anaphylaxis - rare but potentially life-threatening
• Memory impairment and confusion - more common in elderly patients
• Aggravation of dementia symptoms - when used with cholinesterase inhibitors 1

Discontinuation Rates

High-quality evidence shows that tolterodine has a better side effect profile compared to some other antimuscarinic medications:

• Tolterodine has discontinuation rates due to adverse effects similar to placebo (unlike fesoterodine, oxybutynin, propiverine, solifenacin, and trospium which have higher discontinuation rates) 2
• Approximately 7% of patients treated with tolterodine 2mg twice daily discontinue treatment due to adverse events, comparable to 6% with placebo 1

Cardiovascular Effects

• No significant ECG changes in QT and QTc intervals have been demonstrated in clinical studies with standard dosing 1
• Post-marketing reports include tachycardia and palpitations, though causality is difficult to establish 1
• Patients with a history of QT prolongation or those taking medications that prolong QT interval should use tolterodine with caution 1

Special Populations

Elderly Patients

• Safety profile is similar in patients aged ≥65 years compared to younger adults 3
• However, elderly patients may be more susceptible to cognitive effects and confusion 1

Patients with Impaired Hepatic Function

• Dosage adjustment is recommended in patients with hepatic impairment 4
• Metabolism is reduced, leading to higher blood levels and potentially more side effects

Drug Interactions

• CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin): May increase tolterodine levels, requiring dosage reduction 3
• CYP2D6 inhibitors: May affect metabolism of tolterodine 4
• Cholinesterase inhibitors: Potential for worsening of dementia symptoms when used concurrently 1

Comparison to Other Antimuscarinic Medications

• Tolterodine has a more favorable side effect profile than oxybutynin:

  • Dry mouth and insomnia occur less frequently with tolterodine than oxybutynin 2
  • Discontinuation due to adverse effects is higher with oxybutynin than tolterodine (high-quality evidence; NNTH, 14 [CI, 7 to 145]) 2

• Compared to fesoterodine:

  • Dry mouth and headache are less common with tolterodine 2
  • Discontinuation due to adverse effects is lower with tolterodine 2

Monitoring and Management

• Monitor for signs of urinary retention, especially in patients with bladder outlet obstruction
• Be alert for cognitive changes, especially in elderly patients
• Manage dry mouth with adequate hydration, sugar-free gum/candy, or saliva substitutes
• Consider dose reduction if side effects are troublesome but the medication is effective
• Discontinue medication if serious adverse effects occur

Tolterodine remains an important treatment option for overactive bladder with a relatively favorable side effect profile compared to other antimuscarinic medications, particularly regarding dry mouth and treatment discontinuation rates.