What is the usual dose of cyproheptadine for nightmares in Post-Traumatic Stress Disorder (PTSD)?

Cyproheptadine Dosing for PTSD-Associated Nightmares

For PTSD-associated nightmares, cyproheptadine is typically dosed at 4-8 mg at bedtime, with some patients requiring up to 12 mg daily for adequate symptom control. 1

Dosing Recommendations

Initial Dosing

• Start with 4 mg at bedtime
• Titrate based on response and tolerability

Dosing Range

• Therapeutic range: 4-12 mg daily
• Most common effective dose: 4-8 mg at bedtime
• Some patients may require higher doses (up to 16-24 mg) in treatment-resistant cases 1

Response Timeline

• Onset of effect: Often within a few days
• Full response assessment: 3-4 weeks 1

Evidence Quality and Considerations

The evidence for cyproheptadine in PTSD-associated nightmares is limited and shows mixed results:

• Case series have shown variable efficacy:

  • One small case series (n=4) showed elimination of nightmares in 3 patients at doses of 2-6 mg nightly 1
  • Another case series (n=16) showed no significant improvement at doses of 4-8 mg 1
  • A retrospective review found responses ranging from complete remission to decreased intensity/frequency at doses of 4-12 mg daily 2

• Side effect profile:

  • Common: Fatigue, restlessness 1
  • Less common but concerning: Visual hallucinations (worsened flashbacks) 1

Alternative First-Line Options

It's important to note that cyproheptadine is not considered first-line therapy for PTSD-associated nightmares:

• Prazosin is the recommended first-line medication (Level A evidence) 1, 3

  • Starting dose: 1 mg at bedtime
  • Titrate upward by 1-2 mg every few days
  • Effective dose range: 1-10+ mg (average ~3 mg)
  • Maximum dose: up to 20 mg at bedtime 4

• Clonidine may be considered (Level C evidence) 1

  • Typical dose: 0.1 mg twice daily 3

Clinical Pearls

• Monitor for sedation, which may be beneficial for nighttime dosing but problematic during daytime
• FDA-approved adult dosing for cyproheptadine (for other indications) is 4-20 mg daily, not to exceed 0.5 mg/kg/day 5
• Response to cyproheptadine should be assessed within 3-4 weeks
• Consider discontinuation if no improvement after 4 weeks of treatment at adequate dosage
• Cyproheptadine works as a serotonin receptor antagonist, potentially affecting 5-HT1A receptors of the midbrain raphe 1

Monitoring

• Assess nightmare frequency and intensity before and during treatment
• Monitor for side effects, particularly excessive daytime sedation
• Evaluate impact on overall sleep quality and daytime functioning
• Consider using a sleep diary to track improvements

Remember that effective treatment of nightmares in PTSD can lead to improved quality of life, fewer hospital admissions, lower healthcare costs, and reduced all-cause mortality 6.