Taking NyQuil for Sleep

While using NyQuil as directed is thought to be safe, taking it in ways that are not recommended, like as a primary sleep aid, can be dangerous.

NyQuil is a common cold and flu relief medication sold over the counter in either liquid or pill form. It is usually used to relieve coughing, but it also produces a feeling of relaxation and drowsiness. Additionally, some people who have conditions with associated pain use NyQuil to help maintain a pain-free state of sleep.

Because NyQuil is thought to produce a deep and enduring state of sleep, people often ask, “Can you take NyQuil just to sleep?” or, “Can I use NyQuil as a sleep aid?” A few aspects of NyQuil need to be considered to answer these questions.

What Does NyQuil Do?

Nyquil treats bothersome symptoms of the cold and flu that might otherwise keep a person awake at night. These symptoms can include pain, cough and sneezing. To alleviate symptoms, NyQuil contains three ingredients:

• Acetaminophen, an analgesic to stop pain like headaches
• Dextromethorphan, a cough suppressant
• Doxylamine, an antihistamine 

Can You Take NyQuil as a Sleep Aid?

You should avoid taking NyQuil as a sleep aid. Though NyQuil contains ingredients like doxylamine that are often prescribed for sleep, relying on NyQuil for sleep is not advised. Besides doxylamine, NyQuil contains other active ingredients like alcohol that should not be used for sleep. And even doxylamine is only meant as a short-term sleep aid. Like any drug that can assist with either falling asleep or maintaining sleep throughout the night, using NyQuil regularly may be problematic.

What Ingredient in NyQuil Makes You Sleepy? 

A main component of NyQuil is doxylamine, an antihistamine that causes drowsiness by blocking histamine from attaching to receptors in the brain. Because doxylamine succinate doesn’t discriminate between which histamine receptors they block, they cross the blood–brain barrier and inhibit receptors involved with the regulation of sleep (just one of the important functions of histamines). The disruption of this particular function of histamines in the brain results in drowsiness.

NyQuil also includes the ingredient dextromethorphan, which suppresses coughing. However, as it metabolizes in the body, it becomes dextromethorphan (DXM). Considered a dissociative drug by the experts, DXM is an NMDA receptor antagonist that acts primarily as an antitussive (cough suppressant) but has dissociative hallucinogenic properties like those found when using ketamine and PCP (phencyclidine). These properties are much less severe in NyQuil and are unlikely to be experienced unless NyQuil is being abused at very high doses.

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Are There Side Effects to Using NyQuil for Sleep?

Taking NyQuil can make people drowsy and fall asleep, which is the major side effect of the drug. The duration and quality of sleep can vary depending on the person. Other, rarer, side effects are mainly due to the acetaminophen component and can include:

• Skin reddening
• Blisters
• Rash
• Liver damage

How Long Does NyQuil Last?

NyQuil’s effects last about six hours. The drug can be taken every six hours as a result.

Is It Safe To Take NyQuil To Sleep When Not Sick?

It is best to avoid taking NyQuil for sleep when you are not sick. The medication includes multiple ingredients like acetaminophen, dextromethorphan and even alcohol, which are unnecessary to help you get to sleep, and, in the case of alcohol, can even prevent a good night’s sleep by interfering with your sleep cycles. The main NyQuil ingredient that causes sleepiness, doxylamine, can be taken on its own for sleep and even prescribed by a doctor for this purpose. If NyQuil has helped you sleep in the past and you are tempted to use it even when not sick, ask your doctor if it is safe for you to take doxylamine.

Can You Get Addicted to NyQuil?

NyQuil is not an addictive drug, and none of its components are controlled substances. That said, some NyQuil products contain alcohol, which can be addictive.

Nonetheless, while using NyQuil as directed is thought to be safe, taking it in ways that are not recommended can be dangerous.

With extended use, some people may notice that the typical amount they consume does not produce the same effect. Instead, it may take longer to fall asleep, or they may not be sleeping as long. Taking larger doses or more frequent doses to achieve the same effect usually indicates that the body has developed a tolerance to the NyQuil and is likely to have formed a physical dependence.As with any drug, this situation should be treated as a serious condition. Withdrawal symptoms can occur if you suddenly stop, and the individual should seek assistance from medical or mental health providers.

Editor – Abby Doty

Abby Doty graduated from Hamline University in 2021 with a Bachelor's in English and Psychology. She has written and edited creative and literary work as well as academic pieces focused primarily on psychology and mental health. Read more

Medically Reviewed By – Dr. Jessica Pyhtila, PharmD

Dr. Jessica Pyhtila is a Clinical Pharmacy Specialist based in Baltimore, Maryland with practice sites in inpatient palliative care and outpatient primary care at the Department of Veteran Affairs. Read more