Zolpidem

Zolpidem is a hypnotic drug used for the short-term treatment of sleep disorders and to improve sleep duration and quality due to its sedative and sleep-inducing effects. The active ingredient is characterized by its low risk of dependence, withdrawal and tolerance, and may also be effective in restoring brain function after brain injury.
In the USA and Germany, the drug is currently the most prescribed sleep aid.

Pharmacodynamics

In the central nervous system, zolpidem binds with high affinity to the α- and γ-subunit of the GABAA receptor, interacts with it, and enhances the sedative and sleep-promoting responses of the neurotransmitter GABA (gamma-amino-butyric acid). This triggers muscle relaxant and anticonvulsant effects and facilitates sleep onset and duration.

Pharmacokinetics

The hypnotic is rapidly absorbed from the gastrointestinal tract and acts quickly after oral administration. The bioavailability in this case is about 70%. In the blood, the maximum plasma concentration is reached after 0.5-3 hours and it circulates about 90% bound to proteins. The volume of distribution is 0.54-0.68 l/kg, decreasing in the elderly and increasing in patients with chronic renal insufficiency.
Zolpidem is metabolized in the liver by various cytochrome P450 isoenzymes into inactive metabolites, which are excreted mainly by the kidneys. The half-life averages 2.4 hours.

Drug Interactions

While taking zolpidem, interactions may occur with alcohol, centrally depressant drugs and antidepressants(bupropion, desipramine, venlafaxine, sertraline, fluoxetine), fluvoxamine, narcoanalgesics, ciprofloxacin, and drugs metabolized by CYP3A4 and CYP450.

Side effects

Common side effects include:

• Hallucinations, restlessness, nightmares, depression
• drowsiness, fatigue, headache, dizziness, cognitive dysfunction, reduced memory
• diarrhea, nausea, vomiting, abdominal pain
• Back pain

Furthermore, zolpidem greatly affects the ability to drive and operate machinery.

Toxicological data

Symptoms and consequences of zolpidem overdose may range from impaired consciousness, morbid drowsiness and coma to cardiorespiratory collapse with fatal outcome.
The LD50 value after oral administration to male rats is 695 mg/kg.