What is the dose of cyproheptadine?

Cyproheptadine Dosing Guidelines

The recommended dose of cyproheptadine varies by age group, with adults typically requiring 12-24 mg over 24 hours for serotonin syndrome, and daily doses of 4-20 mg for other indications, while pediatric dosing is weight-based at approximately 0.25 mg/kg/day.

Adult Dosing

For Serotonin Syndrome

• For severe serotonin syndrome, the recommended dosing is 12 to 24 mg over 24 hours, typically starting with 12 mg, followed by 2 mg every 2 hours for continuing symptoms 1
• A maintenance dose of 8 mg every 6 hours is often used after initial symptom control 1
• There is no parenteral form, but tablets can be crushed and administered via nasogastric tube if needed 1

For General Use

• The therapeutic range for adults is 4 mg to 20 mg per day, with most patients requiring 12 mg to 16 mg per day 2
• The total daily dose should not exceed 0.5 mg/kg/day 2
• Typical starting dose is 4 mg (1 tablet) three times a day, adjusted according to patient response 2
• Some patients may require up to 32 mg per day for adequate relief 2

Pediatric Dosing

For Serotonin Syndrome

• The pediatric dosage for serotonin syndrome is 0.25 mg/kg per day 1, 3

For Children Ages 2-6 Years

• Dosage is calculated based on body weight (0.25 mg/kg/day) or body surface area (8 mg per square meter) 2
• Usual dose is 2 mg (½ tablet) two or three times a day 2
• Maximum daily dose should not exceed 12 mg 2

For Children Ages 7-14 Years

• Usual dose is 4 mg (1 tablet) two or three times a day 2
• Maximum daily dose should not exceed 16 mg 2

Special Considerations

For Autism Spectrum Disorder

• When used in combination with haloperidol for autism, cyproheptadine has been titrated up to 0.2 mg/kg/day 1

For Functional Gastrointestinal Disorders

• Mean effective dose in children with functional gastrointestinal disorders was 4.85-5.34 mg/day (approximately 0.14 mg/kg/day) 4

For Cancer-Related Cachexia

• Used as an appetite stimulant in children with cancer-associated cachexia to prevent weight loss 5

Side Effects and Monitoring

• Most common side effects include somnolence (13%), weight gain (10%), and drowsiness 6, 4
• In children, excitation, hallucinations, ataxia, tachycardia, and muscle twitchings have been reported with accidental overdose 7
• When used for serotonin syndrome, monitor for hypotension as cyproheptadine may cause this side effect 3
• In therapeutic doses, cyproheptadine can reduce secretion of ACTH, cortisol, prolactin, and growth hormone 7

Clinical Pearls

• For serotonin syndrome, cyproheptadine is the preferred antidote by most experts 1, 3
• Patients with serotonin syndrome can deteriorate rapidly; close observation and preparation for rapid intervention is essential 1
• For nightmare disorder in adults, doses ranging from 2-6 mg nightly have been effective, with effects noticed within a few days 1
• For PTSD-related nightmares, doses of 4-12 mg per day have shown variable effectiveness 1

Remember that dosing should be adjusted based on clinical response and tolerability for each individual patient.