From the Guidelines
Cyproheptadine overdose is a medical emergency that requires immediate attention, and treatment typically involves supportive care, including monitoring vital signs and managing symptoms as they arise, with no specific antidote available 1. The management of cyproheptadine overdose involves a comprehensive approach to address the potential complications associated with this condition.
Key Considerations
- Symptoms of overdose include extreme drowsiness, confusion, dilated pupils, rapid heartbeat, flushing, hallucinations, seizures, and in severe cases, coma.
- Treatment typically involves supportive care, including monitoring vital signs, administering activated charcoal if the ingestion was recent (within 1-2 hours), and possibly gastric lavage 1.
- There is no specific antidote for cyproheptadine overdose, and healthcare providers will treat symptoms as they arise, which may include managing anticholinergic effects with physostigmine in severe cases, controlling seizures with benzodiazepines, and providing respiratory and cardiovascular support as needed.
- Cyproheptadine is an antihistamine with anticholinergic properties that blocks histamine H1 receptors and serotonin receptors, which explains why overdose can cause both antihistaminic effects (sedation) and anticholinergic effects (dry mouth, blurred vision, urinary retention) 1.
Treatment Approach
- The dosage of cyproheptadine for treating serotonin syndrome is usually 12 to 24 mg over 24 hours, typically starting with 12 mg, followed by 2 mg every 2 hours for continuing symptoms, and a maintenance dose of 8 mg every 6 hours, given orally 1.
- In cases of overdose, the treatment approach should prioritize supportive care and symptom management, with a focus on preventing further complications and promoting recovery.
- Recovery usually occurs within 24-48 hours with appropriate medical care, though complications can arise in severe cases or when the overdose involves multiple medications 1.
From the Research
Cyproheptadine Overdose
- Cyproheptadine is a serotonin and histamine antagonist that has been suggested as a treatment for serotonin syndrome in case reports 2.
- There is a lack of evidence to support the efficacy of cyproheptadine or its recommendation in clinical guidelines pertaining to the management of serotonin toxicity 3.
- Cyproheptadine overdose is uncommonly reported in the medical literature, with a rare case of a pediatric cyproheptadine overdose with a confirmatory cyproheptadine level reported in one study 4.
Treatment of Serotonin Syndrome with Cyproheptadine
- The role of specific serotonin receptor antagonists such as cyproheptadine in the treatment of the serotonin syndrome remains to be delineated, and its use should be considered an adjunct to supportive care 5.
- A retrospective study of 23 adult patients with serotonin syndrome found that all patients showed at least some response to cyproheptadine within 24 h, with any response to cyproheptadine at a therapeutic dose within 24 h potentially being a diagnostic indicator of the existence of serotonin syndrome 6.
- The dosing schedule for cyproheptadine is not uniform in the literature, with varying regimens reported in different studies 3, 6.
Clinical Features and Management
- Hyperreflexia, clonus, tachycardia, and tremor are common clinical features of serotonin syndrome, with other features including rigidity, increased bowel sound, diaphoresis, fever, hypertension, and myoclonus 6.
- Management of serotonin syndrome involves the administration of a serotonin antagonist such as cyproheptadine, as well as supportive care 2, 5, 6.