What is the recommended dosing for amitriptyline (tricyclic antidepressant)?

Amitriptyline Dosing Recommendations

For amitriptyline, start with 10-25 mg at bedtime and gradually increase by 25 mg every 3-7 days as tolerated, up to a maximum of 150 mg daily for most conditions. 1, 2

Initial Dosing Strategy

Amitriptyline dosing should follow these principles:

• Starting dose:

  • Standard adult starting dose: 10-25 mg at bedtime 1
  • Elderly or medically frail patients: Lower starting dose of 10 mg at bedtime 1, 2

• Titration schedule:

  • Increase by 25 mg every 3-7 days as tolerated 1
  • For neuropathic pain conditions, slower titration may be appropriate 1
  • Increases are best made in the late afternoon and/or bedtime doses 2

Maximum Dosing by Indication

1. Neuropathic pain:

   • Maximum: 150 mg daily 1
   • Duration of adequate trial: 6-8 weeks with at least 2 weeks at maximum tolerated dose 1

2. Depression:

   • Outpatients: Up to 150 mg daily 2
   • Hospitalized patients: May require up to 200-300 mg daily in severe cases 2
   • Maintenance: 50-100 mg daily (some patients may only need 40 mg daily) 2

3. Headache prevention:

   • Most patients respond to lower doses (10-25 mg daily) 3
   • Maximum doses typically range from 25-100 mg daily 3

4. Insomnia:

   • Low doses of 10-20 mg at bedtime are typically effective 4

Special Populations

• Elderly patients:

  • Lower doses recommended: 10 mg three times daily with 20 mg at bedtime 2
  • Slower titration and closer monitoring due to increased risk of side effects 1
  • Higher plasma levels occur for a given oral dose compared to younger patients 2

• Adolescents:

  • Lower doses recommended: Similar to elderly dosing 2
  • 10 mg three times daily with 20 mg at bedtime may be sufficient 2

• Pediatric patients (under 12):

  • Not recommended due to lack of experience in this population 2

Administration Considerations

• For maintenance therapy, the total daily dose may be given as a single dose at bedtime 2
• Sedative effects typically appear before antidepressant effects 2
• Therapeutic effects may take up to 30 days to develop 2
• Maintenance therapy should continue for at least 3 months to reduce relapse risk 2

Monitoring and Adverse Effects

• Most common adverse effects: sedation, dry mouth, constipation, urinary retention, and blurred vision 1
• Daytime fatigue is reported in approximately 11% of patients 3
• Anticholinergic side effects are more common with amitriptyline than with secondary amine TCAs like nortriptyline 1
• Blood concentration monitoring may be useful in identifying toxicity or non-compliance 2
• Target therapeutic blood level: active medication and metabolite <100 ng/mL 1

Clinical Pearls

• Lower doses (10-25 mg) are often effective for pain conditions and may improve medication persistence 3
• For neuropathic pain, the analgesic effect is independent of antidepressant activity and occurs at lower doses than required for depression 1
• Amitriptyline has potential for abuse, though this is rare 5
• In irritable bowel syndrome, low-dose titrated amitriptyline (10-30 mg) has shown effectiveness as a second-line treatment 6
• For headache prevention, most patients respond to doses of 10-25 mg daily, which is lower than doses used in many clinical trials 3