Does DayQuil Keep You Awake? How It Affects Your Sleep?

12/30/2025

What is DayQuil intended for?

DayQuil is a combination medication prescribed to treat a range of symptoms, including cough, body aches, stuffy nose, fever, sore throat, and headache. These symptoms are usually caused by conditions such as the common cold, the flu, and breathing illnesses like bronchitis and sinusitis.

This medication contains three active ingredients: acetaminophen, dextromethorphan, and phenylephrine. Dextromethorphan comes as a cough suppressant that primarily affects a specific part of the brain, which, as a result, reduces the urge to cough. Phenylephrine is a decongestant that helps ease a stuffy nose. On the other hand, acetaminophen is a non-aspirin fever reducer and pain reliever. This mediation is not the right choice for ongoing coughs due to smoking, asthma, and other long-term breathing issues.

This medication should not be used in children younger than 6 years to treat cold symptoms unless otherwise directed by the doctor.

Does DayQuil make you drowsy?

DayQuil is generally marketed as a non-drowsy medication, but its active ingredient, phenylephrine, can cause jitteriness, nervousness, and difficulty sleeping in certain individuals. This medication is designed for daytime use and doesn’t cause drowsiness like other nighttime medications, such as NyQuil. The active ingredient, phenylephrine,  works by narrowing blood vessels in the nasal passages to minimize stuffiness. This mechanism of action may have stimulant-like effects in certain individuals and may cause the aforementioned symptoms.

It is important to pay attention to how medication works for you. If you find it affecting your sleep or keeping you awake, try to take it at least 4 hours before bedtime. In addition to this, don’t take DayQuil and NyQuil together due to the increased risk of side effects and drug interactions.

Warnings & precautions to be exercised while on DayQuil

• It is imperative to check the DayQuil ingredients before you start taking it. If you seem to be allergic to any of these ingredients, including both active and inactive ingredients, please let your doctor know. It contains three major active ingredients: acetaminophen, dextromethorphan, and phenylephrine. If taken despite being allergic to it, it may cause serious complications, including allergic reactions.

• One of its ingredients is acetaminophen. Consuming too much acetaminophen can lead to serious liver disease. Adults should not consume more than 4 gm of acetaminophen a day. If you have liver problems or need to administer to your children, try to give as little as possible. Meet your doctor to know how much is safe for you based on your health.

• Try to refrain from using other products that contain acetaminophen without consulting your doctor. Acetaminophen can be seen in many prescription and non-prescription drugs. Therefore, please check the label of your medication to prevent unwanted complications.

• It is important to seek medical help right away if you have consumed too much acetaminophen. The following are the symptoms of an acetaminophen overdose: nausea, loss of appetite, sweating, vomiting, stomach pain, dark urine, etc.

• It is paramount to share the medical history with your healthcare provider, especially of diabetes, trouble urinating, heart problems, glaucoma, high blood pressure, kidney problems, liver disease, etc. This will help your doctor determine whether it is safe for you.

• The consumption of this drug can cause dizziness or drowsiness. Therefore, kindly refrain from using alcohol or marijuana since they can exacerbate these effects. In addition to this, don’t engage in activities that may require alertness or coordination, such as driving and operating heavy machinery.

• This medication is also available in other forms, such as liquid and chewable tablets. These forms may contain sugar, aspartame, or alcohol. Caution is advised, especially for people with conditions such as alcohol dependence, diabetes, phenylketonuria, etc.

Is DayQuil free of side effects?

DayQuil is an over-the-counter product that most people consider free from side effects. However, the reality is more complex. DayQuil is not free of side effects; it may cause mild to serious effects. Mild or common side effects usually occur during the first few days of treatment, as the body adjusts to the medication. If they persist or exacerbate over time, it is important to seek medical attention. On the other hand, serious side effects are rare, but cannot be ruled out completely. Therefore, if you stumble upon any serious side effects, get in touch with your medic.

Common side effects:

• Lightheadedness

• Drowsiness

• Stomach pain

• Nausea

• Vomiting

• Nervousness

• Dizziness

• Trouble sleeping

Serious side effects:

• Rash

• Difficulty breathing

• Trouble swallowing

• Itchiness

• Hives

• Itching

• Swelling of your face, throat, tongue, or lips

• Swelling of your hands, legs, ankles, or feet

• Red, peeling, or blistering skin

Does DayQuil interact with other medications?

Drug interactions can change how your medication works or augment your risk of experiencing side effects. Therefore, make sure to share the list of all medications you might be on with your healthcare provider. This document does not list all medications that may interact with DayQuil. Don’t quit, start, or change any dosage of the medication you are on without consulting your doctor.

Taking MOA inhibitors with this medication can result in serious drug interactions. Therefore, avoid taking MOI inhibitors during treatment with this medication. All MOI inhibitors should be stopped at least 2 weeks before starting the treatment with DayQuil. Make sure to consult your doctor for a better understanding.

If you are taking other medications that may yield drowsiness, such as opioid pain relievers, cough relievers, alcohol, marijuana,  muscle relaxants, antihistamines, etc, let your doctor know about it. This will reduce the possibility of drug interaction and other complications, including excessive drowsiness.

The use of this medication may interfere with certain urine laboratory tests, such as 5-HIAA levels, potentially yielding false results. Inform the physician and laboratory personnel about this medication before undergoing any laboratory tests.

How should you use DayQuil?

Kindly abide by the following directions while using this medication to get the maximum results:

• Make sure to review all the directions on the product package.  If you have any concerns or doubts, discuss them with your doctor or pharmacist.

• It is to be taken orally with or without food or as directed by your doctor. If you experience an upset stomach after consuming it, try taking it with food or milk.

• If you are using the liquid form of this medication, use a measuring device for accurate measuring. Please don’t use a household spoon, as it may not help you obtain the correct dosage.

• Chewable tablets are meant to be chewed thoroughly before swallowing.

Conclusion:

DayQuil contains three active ingredients that work together to help you feel better by alleviating the symptoms of the common cold and flu. These three active ingredients can lead to side effects, interact with other drugs, and may affect certain health conditions. Therefore, it is important to consult your physician before starting this medication. Inform your doctor about your medical history, along with the medications you are taking. This medication should be taken as advised by the doctor for the best results. It is less likely to induce serious side effects; if you experience any serious side effects. Let your doctor know.