Does the Incidence of Rhabdomyolysis Induced by Doxylamine Overdose Increase in the Elderly

Background: Doxylamine is an over-the-counter drug that is popular in the treatment of insomnia. Doxylamine is relatively safe but can cause rhabdomyolysis. The aim of this study was to evaluate whether the incidence of rhabomyolysis increased in elderly patients (age≥65 years) with doxylamine overdose. Methods: This study included 108 patients admitted to an Emergency Department after doxylamine overdose between January 1, 2000, and March 31, 2013. Age, sex, time ingested before admission, amount of drug ingested, gastric lavage, tachycardia, vomiting, hematuria, blood urea nitrogen, blood creatinine, urine pH, and alcohol ingestion were investigated for the risk factors of rhabdomyolysis. Results: Forty-three patients (47.6%) developed rhabdomyolysis. Of 16 elderly patients, 11 developed rhabdomyolysis. Of the 92 patients <65 years-of-age, 34 developed rhabdomyolysis. Advanced age, alcohol ingestion, and increased blood creatinine level were significantly associated with the development of rhabdomyolysis. Conclusion: In elderly patients with doxylamine overdose, the incidence rate of rhabdomyolysis may be increased. A high index of suspicion and evaluation of rhabdomyolysis is warranted in elderly patients with doxylamine overdose.