Insomnia Drug May Wake Coma Patients

A drug used to treat insomnia has helped temporarily rouse three men who were each in a vegetative state following motor accidents, according to a new study.

Researchers at the Royal Surrey County Hospital (Guildford, UK) believe that zolpidem, manufactured by Sanofi-Aventis (Paris, France) activates receptors for the neurotransmitter gamma aminobutyric acid (GABA) in the brain. According to the researchers, brain injury may alter GABA receptors, causing regions of the brain to remain dormant. They speculate that zolpidem can possibly, temporarily reverse this change. Their findings were reported in the May 2006 issue of NeuroRehabilitation.

The new study details the effects of the drug in three patients, all of whom have been in a permanent vegetative state (PVS) for at least three years. People in this state may have regular sleep cycles but do not show detectable awareness. The men received daily doses of zolpidem for up to six years.

Before treatment with the drug, Patient L did not respond to any commands and showed no signs of language comprehension. After taking his first dose, 10 mg of zolpidem, the patient could meaningfully interact with family, friends, and strangers. He could name his favorite rugby player and make simple calculations. The effects of the drug seemed to last for approximately four hours, after which Patient L would relapse into the vegetative state. Before taking zolpidem, Patient N scored six out of a possible 15 points on the Glasgow coma scale. With the medication, his score improved to 10. The third man, Patient G, showed no response to language prior to drug treatment but could count to five after receiving the medication. His score on the Glasgow coma scale improved temporarily from nine to 14 points.

A coma score of 13 on the Glasgow coma scale--a measure of responsiveness---or higher correlates with mild brain injury while a score of eight or less is generally considered severe brain injury.



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