Objectives: To identify the epidemiological characteristics and clinical outcome in patients who intentionally ingested cyproheptadine or cyproheptadine-containing sleeping pills, and to investigate any association between dose ingested and reported adverse effects.
Method: A retrospective study was performed based on data from the Hong Kong Poison Information Centre from July 2005 to December 2009. Fifty-seven eligible patients were recruited. Patients' epidemiological data, type and dose of cyproheptadine or cyproheptadine-containing sleeping pills ingested, symptoms, clinical outcome, and length of stay in hospital were reviewed.
Results: The majority of patient with intentional overdose had no (42.1%) or mild (40.4%) sedative symptoms. Some 17% of patients developed anticholinergic symptoms, such as delirium, agitation, disorientation, and hallucination. The mean dose ingested was found to be significantly higher in patients who presented with delirium (188.6 mg) than those who were asymptomatic (49.8 mg) (p < 0.001). The time of symptom onset in all symptomatic patients was less than 6 h.
Conclusions: The majority of patients with intentional cyproheptadine overdose had no or mild symptoms only. Patients who have ingested a significant amount of cyproheptadine are more prone to develop delirium. Patients who remain asymptomatic 6 h after exposure are unlikely to develop serious symptoms.