Clinical Features of the Patients with Seizures after Doxylamine Succinate Overdose

Cho, Hanna; Lee, Myung Jun; Sim, Jae Eun; Kim, Won Joo

Abstract

PURPOSE
Doxylamine succinate is an over-the-counter drug commonly used in the treatment of insomnia. It is in the ethanolamine class of antihistamine and is frequently involved in intentional overdoses. Seizures are uncommon, but there are potentially serious complications, making early recognition and treatment essential.
METHODS
We reviewed retrospectively the medical records of patients admitted for seizures after a doxylamine succinate overdose from Jan. 1, 1992 to Dec. 31, 2008. We evaluated them with respect to age, sex, amount ingested, clinical symptomatology, time from ingestion to seizure, complication, and prognosis.
RESULTS
Among the 146 doxylamine overdose patients, 11 patients developed seizures. Females accounted for 9 (81.8%) patients and the number aged between 20 and 40 years was also 9 cases (81.8%). The average time from ingestion to emergency room visit was 170 minutes (60-360). The average time from ingestion to development of seizures was 188 minutes (60-480). The amount of doxylamine succinate ingested was 750-4,750 mg (mean = 2,425 mg). The frequent anticholinergic symptoms were tachycardia (63.6%), vomiting (45.5%), mydriasis (36.4%), and hypertension (36.4%). Rhabdomyolysis and drug induced hepatitis were observed in 7 cases (63.6%) and 6 cases (54.5%), respectively. Primary treatment included administration of benzodiazepine and conservative care. After more than a 6 month follow-up, no patients developed further seizure.
CONCLUSIONS
The incidence of seizure after doxylamine succinate overdose is uncommon and prognosis is good. However, other serious symptoms are commonly combined, and we have to be aware that seizures are a potential complication and should be actively investigated and vigorously treated.