Z-drugs

Zolpidem.svg

Z-drugs are a class of medications that are primarily used for the treatment of insomnia. They are non-benzodiazepine hypnotics that act on the GABA receptor, specifically the GABA_A receptor, to produce a sedative effect. The most commonly prescribed Z-drugs include zolpidem, zaleplon, and eszopiclone.

Pharmacology

Z-drugs work by enhancing the activity of the neurotransmitter gamma-aminobutyric acid (GABA) at the GABA_A receptor. This action increases the inhibitory effects of GABA, leading to sedation and hypnosis. Unlike benzodiazepines, Z-drugs are more selective for the α1 subunit of the GABA_A receptor, which is thought to be responsible for their hypnotic effects.

Zolpidem

Zolpidem is one of the most widely used Z-drugs. It is available in immediate-release and extended-release formulations. Zolpidem is known for its rapid onset of action and short half-life, making it suitable for patients who have difficulty falling asleep.

Zaleplon

Zaleplon has an even shorter half-life than zolpidem, which makes it particularly useful for patients who have trouble falling asleep but do not have issues with staying asleep. It is less likely to cause next-day sedation due to its rapid elimination from the body.

Eszopiclone

Eszopiclone is the S-enantiomer of zopiclone and is used for both sleep onset and sleep maintenance. It has a longer half-life compared to zolpidem and zaleplon, which can be beneficial for patients who experience frequent awakenings during the night.

Clinical Use

Z-drugs are primarily prescribed for short-term management of insomnia. They are effective in reducing sleep latency and increasing total sleep time. However, they are generally recommended for short-term use due to the risk of dependence and tolerance.

Side Effects

Common side effects of Z-drugs include dizziness, headache, and gastrointestinal disturbances. More serious side effects can include complex sleep-related behaviors such as sleepwalking, sleep-driving, and engaging in other activities while not fully awake. There is also a risk of developing dependence with prolonged use.

Comparison with Benzodiazepines

While both Z-drugs and benzodiazepines act on the GABA_A receptor, Z-drugs are considered to have a more favorable side effect profile, particularly in terms of reduced risk of dependence and less next-day sedation. However, both classes of drugs can lead to tolerance and withdrawal symptoms.

Regulation and Prescription

Z-drugs are classified as controlled substances in many countries due to their potential for abuse and dependence. Prescriptions are typically limited to short durations, and patients are advised to use the lowest effective dose.

Also see

• Insomnia
• Benzodiazepine
• GABA receptor
• Hypnotic
• Sedative