Ajitha Sharma1, Prakash S Rama2. 1. Department of Pharmacology, Pondicherry Institute of Medical Sciences, Puducherry, India. 2. Department of Emergency Medicine Services, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India.
Sir,We read with great interest the report on zolpidem causing sleep-walking by Singh et al.[1] A few reports on this rare adverse effect of zolpidem have been described from various parts of the world, as mentioned by the authors. In addition, we came across a few more similar case reports.[23] Zolpidem is a non-benzodiazepine hypnotic agent, acting on α1 subunit of the benzodiazepine (BZD) receptor which is a part of the gamma-aminobutyric acid type A (GABAA) receptor-chloride channel complex. The proposed hypothesis regarding mechanism for zolpidem induced somnambulism is desensitization of GABA receptors located on serotonergic neurons.[4] Though there are scattered reports of somnambulism with zolpidem, the incidence is yet to be determined.In a postmarketing surveillance study, sleep-walking was seen in 7 out of 1972 patients (0.3%).[5] Furthermore, there were few reports of zolpidem causing other parasomnias like sleep-driving and sleep-eating, which could be a source of danger to the patient, as well as others. The Food and Drug Administration issued a request to drug manufacturers to include these warnings in the labels of drugs approved for the treatment of insomnia in December 2006.[6] In spite of these warnings, it is pertinent that zolpidem intake should be carefully scrutinized, and any somnambulism noted be reported so as to determine the incidence of this potentially dangerous adverse effect. Postmarketing surveillance plays a crucial role to this effect and hence the need for a dynamic, relentless monitoring of adverse drug reactions.