Key Points

  • NyQuil is an OTC cold and flu medication.
  • NyQuil’s active ingredients -- dextromethorphan (DXM) and doxylamine -- can induce drowsiness.
  • NyQuil causes drowsiness within 30 minutes.
  • Dextromethorphan -- the cough suppressant in NyQuil -- is sold illicitly under the street names Syrup, Sizzurp, DXM, Lean, and Skittles.[2]
  • You can become dependent on NyQuil if you use it in an abusive fashion or any way other than prescribed.

NyQuil is a widely used over-the-counter medication to relieve common cold and flu symptoms.[1] Its fast-acting ingredients effectively reduce fever, sore throat, body aches, and congestion, allowing the user to relax. Although it is not intended for sleep, NyQuil is known to cause drowsiness, which can lead some people to use it as a sleep aid. However, this is not recommended, as misusing NyQuil can lead to dependency and addiction.

Is NyQuil Supposed to Make You Tired?

NyQuil’s active ingredients—dextromethorphan, acetaminophen, and doxylamine—work together to relieve nasal congestion, cough, pain, fever, and sore throat. Due to the side effects of these ingredients, you may feel drowsy shortly after your first dose, although sleep is not its intended purpose. A typical 30 mg dose includes:[3]
  • Acetaminophen (650 mg) is a non-opioid pain reliever used to treat moderate to severe pain and to reduce fever.[4]
  • Dextromethorphan HBR (30 mg) is a synthetic analog of codeine that works as a cough suppressant.[5]
  • Doxylamine (12.5 mg) is an antihistamine with decongestant properties that relieve both allergy and cold symptoms, such as a runny nose and sneezing.[6]

How Soon Do You Feel Sleepy After Taking NyQuil?

Although NyQuil may not affect everyone in the same way, the Sleep Foundation states that it can induce sleepiness in most people within 30 minutes of consumption.[7] This effect may last throughout the night, so many physicians recommend taking it at bedtime. Taking it during the day can lead to grogginess and an increased risk of injury.

Why Do the Main Ingredients in NyQuil Make You Sleepy?

Why do NyQuil ingredients make you drowsy? The two ingredients in NyQuil that induce drowsiness are dextromethorphan and doxylamine succinate. Dextromethorphan reduces brain activity, which helps alleviate coughing. Although not intended for sleep, it can cause drowsiness as a side effect.[8] Doxylamine succinate works by inhibiting histamine from binding to receptors in the brain. Histamine is a chemical that plays a key role in promoting alertness and wakefulness. When its action is blocked, drowsiness is induced, leading to a decrease in overall alertness.[7]

Is Daytime Drowsiness After Taking NyQuil Normal?

Feeling drowsy after taking NyQuil during the day is common, as is experiencing grogginess the morning after a late-night dose. Research shows that NyQuil’s drowsiness effects can persist throughout the night, and taking the medication later in the evening may prolong these effects until the next day.[7]

Should You Take NyQuil to Help with Sleep?

NyQuil can produce sedative effects, but it is not FDA-approved for use as a sleep aid.[7] However, its active ingredient, doxylamine, can be prescribed separately for short-term treatment of insomnia. For insomnia lasting more than two weeks, medications such as Estazolam or Flurazepam may be more appropriate treatment options.[9]

Can You Become Addicted to NyQuil?

When using NyQuil, following the directions provided on the packaging is important. Using this medication for purposes other than those specified or in doses different from those recommended can lead to tolerance.[10] When your body and brain develop a tolerance to NyQuil, the effects may become less pronounced than they initially were. This may lead you to use a higher dosage to achieve the same effects. Taking more NyQuil than advised can increase the risk of toxicity as well as the potential for addiction. NyQuil toxicity induces troubling symptoms such as the following:[11]
  • Vomiting
  • Diarrhea
  • Fever
  • Involuntary shaking
  • Hallucinations
  • Dilated pupils
  • Impaired motor skills
  • Impaired cognition
  • Jaundice (liver damage)
  • Difficulty breathing
  • Difficulty staying awake
  • Seizure
  • Coma
  • Death
Anyone experiencing a NyQuil overdose should receive emergency medical care.

Signs of a NyQuil Addiction

An individual addicted to NyQuil may feel embarrassed to admit their dependency. They might experience shame about their inability to stop using it and could isolate themselves from family and friends to conceal the visible signs of their addiction. In addition to isolation, someone with a NyQuil addiction may display the following signs:
  • A preoccupation with using NyQuil
  • Appearing drowsy or under the influence regularly
  • Inability to sleep without using it
  • Experiencing anxiety and agitation when attempting to stop using it
  • Feeling restless or jittery without NyQuil
  • Complaining of stomach pain or nausea that is only remedied by using it
  • Stockpiling NyQuil for fear of running out
  • Inability to stop using NyQuil without withdrawal symptoms
It’s important to note that not everyone who uses NyQuil becomes addicted to it. Addiction is the most severe form of a substance use disorder and comes after misusing or abusing the substance.[12]

Getting Help for a NyQuil Addiction

If you or someone you know is struggling with an addiction to NyQuil, there is hope for recovery. At SE Addiction Center TN, we provide a range of evidence-based treatment programs tailored to help you overcome addiction by addressing its root causes and identifying triggers for use. We offer various addiction recovery services, including 12-step support, cognitive behavioral therapy, and peer support groups. Our dedicated team will work with you one-on-one to ensure a safe detox from NyQuil and to equip you with the tools needed to manage cravings and reduce the risk of relapse. To learn more about our fully accredited facility and science-backed programs, contact us today. You have already taken the first step toward sobriety; let us guide you through the rest.