Side Effects of Cyproheptadine
Cyproheptadine commonly causes sedation/drowsiness, increased appetite and weight gain, dry mouth, and other anticholinergic effects, with potential for cognitive impairment especially in elderly patients. 1
Common Side Effects
Cyproheptadine is a first-generation antihistamine with H₁ receptor antagonist properties and additional antiserotonergic and anticholinergic effects. Its most frequently reported side effects include:
- Sedation and drowsiness
- Increased appetite leading to weight gain
- Dry mouth
- Other anticholinergic effects 1
Neurological and Cognitive Effects
- Performance impairment without subjective awareness of sedation (increasing risk of automobile accidents)
- Potential cognitive decline, especially in elderly patients
- Risk of visual hallucinations
- Excitation (particularly in children)
- Ataxia
- Muscle twitching 1, 2
Cardiovascular Effects
Cyproheptadine should be used with caution in patients with:
- Cardiovascular disease
- Hypertension 3
Special Population Considerations
Elderly Patients
- Increased sensitivity to anticholinergic effects
- Higher risk of cognitive impairment
- Dose selection should be cautious, starting at the low end of the dosing range 1, 3
Pediatric Patients
- May occasionally produce excitation rather than sedation
- Safety not established in children under 2 years of age 3, 2
Drug Interactions and Precautions
Cyproheptadine has important interactions and precautions:
Enhanced effects when combined with:
- Alcohol or other CNS depressants (hypnotics, sedatives, tranquilizers)
- MAO inhibitors (which prolong and intensify anticholinergic effects) 3
Should be used with caution in patients with:
Overdose Considerations
In cases of accidental overdose or intentional misuse:
- Symptoms appear rapidly after ingestion
- Effects generally last 6-12 hours
- Severe overdose can be life-threatening, especially when combined with other medications 4, 2
Endocrine Effects
When given in therapeutic doses, cyproheptadine can:
- Reduce secretion of ACTH, cortisol, prolactin, and growth hormone
- Lower blood glucose concentrations
- Raise levels of unesterified free fatty acids 2
Important Warnings
- Patients should be warned about engaging in activities requiring mental alertness and motor coordination (driving, operating machinery)
- Concomitant use with alcohol or sedatives enhances performance impairment 1, 3
Monitoring Recommendations
- Monitor for sedation and cognitive effects, especially in elderly
- Watch for anticholinergic side effects (dry mouth, urinary retention, constipation)
- Monitor weight changes, particularly weight gain
- Be alert for paradoxical reactions in children (excitation rather than sedation)