Canadian Brand Name and Side Effects of Cyproheptadine
The Canadian brand name for cyproheptadine is Periactin, and its common side effects include sedation/drowsiness, increased appetite, weight gain, dry mouth, and other anticholinergic effects. 1, 2
Overview of Cyproheptadine
Cyproheptadine (Periactin) is a first-generation antihistamine with H₁ receptor antagonist properties, as well as additional antiserotonergic and anticholinergic effects. It is primarily used for:
- Allergic conditions (urticaria and rhinitis)
- Appetite stimulation
- Gastrointestinal symptoms
- Treatment of serotonin syndrome 2
Common Side Effects
The most frequently reported side effects of cyproheptadine include:
- Sedation/drowsiness (significant compared to second-generation antihistamines)
- Increased appetite and weight gain (dose-dependent effect)
- Dry mouth
- Other anticholinergic effects including:
- Blurred vision
- Urinary retention
- Constipation
- Cognitive impairment (especially in elderly patients) 2
Special Considerations
Sedation Risk
- Performance impairment may occur without subjective awareness of sedation
- Increased risk of automobile accidents
- Enhanced impairment when combined with alcohol or other CNS depressants 2
Population-Specific Concerns
- Elderly patients: Use with caution due to increased sensitivity to anticholinergic effects and higher risk of cognitive impairment
- Patients with glaucoma: May exacerbate narrow-angle glaucoma
- Patients with prostatic hypertrophy: Increased risk of urinary retention due to anticholinergic effects 1, 2
Dosing Information
For adults, the typical dosage is 4 mg three times daily, with a therapeutic range of 4-20 mg/day and a maximum daily dose of 0.5 mg/kg/day, not to exceed 32 mg/day 2.
Rare but Serious Side Effects
In overdose situations, cyproheptadine can cause:
- Psychosis
- Visual hallucinations
- Severe anticholinergic symptoms
- In rare cases, miotic pupils (unusual for antihistamines) 3, 4
Cyproheptadine should be used with caution in patients with pre-existing conditions such as prostatic hypertrophy, elevated intraocular pressure, and cognitive impairment, as these patients are at higher risk for side effects of first-generation antihistamines 1.