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Z Drugs and Insomnia

Reviewed by: HU Medical Review Board | Last reviewed: June 2024 | Last updated: June 2024

Getting enough sleep is crucial to your overall health. But many people have periods when they struggle to fall asleep or stay asleep through the night. Some people experience this trouble over a long period, called chronic insomnia. Others may have trouble sleeping for a short period because of a life stressor, health problem, or other temporary situation. This is called acute insomnia.1

Doctors may prescribe a group of drugs commonly called Z drugs for acute insomnia. These medicines can help you fall asleep faster and/or stay asleep longer. But they also carry risks that are important to know about.2

How do Z drugs work?

Z drugs are a type of medicine called sedative-hypnotics. Each Z drug may affect the body slightly differently. But in general, Z drugs work on gamma-aminobutyric acid (GABA) receptors in the brain to slow down brain activity.3

GABA is a type of chemical in the brain called a neurotransmitter. GABA calms the nervous system by blocking, or inhibiting, certain chemical messages from moving between nerve cells. It is an important chemical for reducing anxiety and improving sleep.4

Z drugs work similarly to benzodiazepine drugs, another type of drug used to treat insomnia. So, Z drugs are also called “benzodiazepine-like medications” or “nonbenzodiazepines.”3

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Z drugs that are currently approved by the US Food and Drug Administration (FDA) to treat insomnia include:2

  • Zolpidem (Ambien®, Ambien CR®, and Edluar®)
  • Eszopiclone (Lunesta®)
  • Zaleplon (Sonata®)

Zolpidem is the most commonly prescribed hypnotic in the world.3

What are the possible side effects?

Side effects can vary depending on the specific drug you are taking. Common side effects of Z drugs include:5-7

  • Drowsiness, sometimes lasting into the day after taking the medicine
  • Light-headedness or dizziness
  • Headache
  • Dry mouth or a bad taste in the mouth
  • Diarrhea
  • Skin rash
  • Infections

All Z drugs have a boxed warning, the strictest warning from the FDA. They have this warning because they may cause what are called “complex sleep behaviors.” These are potentially dangerous actions you may take while you are asleep. Actions such as sleepwalking and sleep-driving can cause injury or even death.5-7

These are not all the possible side effects of Z drugs. Talk to your doctor about what to expect when taking Z drugs. You also should call your doctor if you have any changes that concern you when taking a Z drug.

Other things to know

Follow your doctor’s exact instructions for taking this medicine, including the time of day and dose amount. Complex sleep behaviors can occur even with low doses. You may not remember taking any action while you were asleep. But if there is any evidence that you were sleepwalking or engaged in another complex sleep behavior, stop taking the medicine right away and contact your doctor.2

Z drugs generally should be taken for only a short time, typically 2 to 4 weeks. If you take a Z drug over a longer period, you may develop a tolerance for the drug. This means you may need to take more and more of it to get the benefits.5-7

Z drugs also can lead to dependence, especially if taken over a prolonged period. Once a person has developed a dependence on a drug, they will likely have withdrawal symptoms when they stop taking the drug. These symptoms may include muscle cramps, excessive sweating, nausea, and more. Also, the anxiety that led to the original bout of insomnia may return in full force.5-7

Do not stop taking a Z drug abruptly. Your doctor will give you instructions on how to stop taking it over time. They also may prescribe another medicine to help reduce withdrawal symptoms while you slowly stop the Z drug.5-7

Do not take any other sleep medicines while taking a Z drug. Taking a Z drug along with another substance with depressive effects, such as alcohol, increases the risk of side effects. Some current medicines may need to be stopped or adjusted when you start a Z drug for insomnia.2,5-7

If a Z drug fails to work after 7 to 10 days of treatment, it may mean there is an underlying condition that needs separate treatment.5-7

Z drugs may not be safe for certain people, including children, pregnant people, and people with liver disease. If you are pregnant, planning to become pregnant, or breastfeeding, talk to your doctor before starting on a Z drug.5-7

Before beginning treatment for insomnia, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you are taking. This includes over-the-counter drugs.

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