GABA mediates the inhibitory actions of local interneurons in the brain. Inhibition of the GABA-ergic pathways may be partially responsible for reduced muscle hypertonia and spread of seizure activity. The presence of food reduces the amount of absorption and increases the time taken to achieve maximum concentration, delaying sleep onset slightly. Zolpidem pharmacokinetics follow a linear profile in the dosage range 520 mg. Pharmacokinetic parameters in patients with end-stage renal failure undergoing hemodialysis, are not significantly different from healthy patients.
Metabolism produces inactive metabolites that are primarily excreted in the urine.
The elimination half-life is about 2.6 hours in patients with normal hepatic and renal function. The mean half-life in healthy patients is 2.2 hours, increased to 2.9 hours in elderly patients and to 9.9 hours for those with chronic hepatic impairment, allowing use of reduced dosage in the elderly and hepatically impaired. Zolpidem is not removed by hemodialysis. Patients with hepatic insufficiency do not clear the drug as rapidly as normals. Problems associated with abrupt discontinuation of hypnotic drugs are more likely to occur following chronic therapy.