What is the dosage and usage of cyproheptadine for treating allergic reactions and stimulating appetite?

Cyproheptadine Dosage and Usage for Allergic Reactions and Appetite Stimulation

For allergic reactions in adults, cyproheptadine should be dosed at 4 mg three times daily (12 mg/day), while for appetite stimulation, doses of 4-8 mg three times daily (12-24 mg/day) are recommended, with adjustments based on response and tolerability. 1

Dosing Guidelines

For Allergic Reactions:

Adults:

• Initial dose: 4 mg three times daily 2, 1
• Therapeutic range: 4-20 mg/day, with most patients requiring 12-16 mg/day 1
• Maximum daily dose: 0.5 mg/kg/day, not to exceed 32 mg/day 1

Children:

• Ages 2-6 years: 2 mg (½ tablet) two or three times daily (0.25 mg/kg/day or 8 mg/m²)
  • Maximum: 12 mg/day 1
• Ages 7-14 years: 4 mg (1 tablet) two or three times daily
  • Maximum: 16 mg/day 1

For Appetite Stimulation:

• Adults: 4-8 mg three times daily 3, 4
• Children with cystic fibrosis: 4 mg up to four times daily 3
• Children with growth hormone deficiency: 0.25-0.4 mg/kg/day 5

Clinical Applications

Allergic Conditions:

Cyproheptadine is effective for treating various allergic conditions as a first-generation antihistamine with:

• H₁ receptor antagonist properties 2
• Additional antiserotonergic and anticholinergic effects 2
• Particularly useful for urticaria and allergic rhinitis 2, 4

Appetite Stimulation:

• Demonstrated effectiveness in improving weight gain in patients with:
  • Cystic fibrosis (CF) 3
  • Growth hormone deficiency 5
• Long-term studies show sustained weight gain with acceptable side effect profile 3

Special Therapeutic Uses:

• Treatment of serotonin syndrome: Initial dose of 12 mg, followed by 2 mg every 2 hours for continuing symptoms, and maintenance dose of 8 mg every 6 hours 2, 6
• Management of PTSD-associated nightmares: 2-6 mg nightly, with some patients requiring 16-24 mg 2
• Treatment of symptoms in mast cell activation syndrome 2

Side Effects and Precautions

Common Side Effects:

• Sedation/drowsiness 2
• Increased appetite and weight gain 3, 4, 5
• Dry mouth and other anticholinergic effects 2

Serious Adverse Effects:

• Potential for cognitive decline, especially in elderly patients 2
• Risk of toxicity in overdose cases 7
• Visual hallucinations (rare) 2

Precautions:

• Monitor for excessive sedation, especially when initiating therapy
• Use with caution in elderly patients due to anticholinergic effects 2
• Avoid abrupt discontinuation after long-term use
• Consider potential drug interactions with other CNS depressants

Clinical Pearls

• Cyproheptadine has dual function as both an H₁ antihistamine and serotonin receptor antagonist, making it particularly useful for treating gastrointestinal symptoms in allergic conditions 2
• The appetite-stimulating effect is dose-dependent and can be beneficial in patients with malnutrition due to chronic illness 3, 5
• When used for serotonin syndrome, cyproheptadine is preferred over chlorpromazine by most experts 2, 6
• For allergic reactions, cyproheptadine may be more effective than newer antihistamines for certain symptoms due to its additional antiserotonergic properties 2
• Weight gain effects typically begin within the first 3-6 months of therapy and can be maintained with continued use 3