NyQuil is a popular over-the-counter medication used to treat cold and flu symptoms. Its main ingredients are acetaminophen (a pain reliever and fever reducer), dextromethorphan (a cough suppressant), doxylamine succinate (an antihistamine) and phenylephrine (a decongestant). One of the well-known side effects of NyQuil is sleepiness or drowsiness. In this article, we’ll take a closer look at how NyQuil works and why it can make people feel sleepy.
What is NyQuil?
NyQuil is a combination cold and flu medication made by Vicks and marketed by Procter & Gamble. It was first introduced in the United States in 1966 and today it comes in several different versions.
The standard green-colored NyQuil contains the following active ingredients per 30 mL dose:
– Acetaminophen – 325 mg
– Dextromethorphan HBr – 15 mg
– Doxylamine succinate – 6.25 mg
– Phenylephrine HCl – 5 mg
Acetaminophen is a pain reliever and fever reducer. Dextromethorphan is a cough suppressant that works by depressing the cough center in the brain. Doxylamine succinate is an antihistamine that reduces runny nose, sneezing and watery eyes. Phenylephrine is a decongestant that constricts blood vessels in the nasal passages, reducing nasal congestion.
So in summary, NyQuil is designed to provide relief from the major symptoms that occur during a cold or flu, including fever, body aches, cough, congestion, runny nose and sneezing. It causes drowsiness as a side effect due to the antihistamine component.
How does NyQuil work?
NyQuil contains a combination of different medications, each with a different mechanism of action targeting specific cold and flu symptoms.
1. Acetaminophen: Reduces fever and body aches by inhibiting COX enzymes and blocking pain pathways in the brain.
2. Dextromethorphan: Suppresses cough by inhibiting cough reflex in the brain.
3. Doxylamine succinate: Reduces runny nose, sneezing and watery eyes by blocking histamine activity at H1 receptors. Histamine is a chemical involved in allergic responses and inflammation.
4. Phenylephrine: Relieves nasal congestion by constricting blood vessels in the nasal passages, reducing swelling and drainage.
When taken together, these ingredients provide broad relief by targeting the underlying causes of cold and flu symptoms. The drowsiness some people experience is a side effect of the antihistamine doxylamine succinate. Antihistamines cross into the brain and bind to H1 receptors, which has a sedating effect.
Does the alcohol in NyQuil make you sleepy?
Most NyQuil products do not actually contain any alcohol. The standard green-colored NyQuil is alcohol-free. However, there are some specialty NyQuil products that do contain a small percentage of alcohol:
– NyQuil Cough: 10% alcohol
– NyQuil Sinus: 10% alcohol
– NyQuil Cold & Flu: 12% alcohol
The alcohol in these products can contribute to drowsiness, but it is not the main reason why NyQuil causes sleepiness. The antihistamine doxylamine succinate in all NyQuil products is responsible for the majority of the drowsy side effects.
So in summary, the alcohol content in some NyQuil products may add to the sleep-inducing effects, but the antihistamine is the primary active ingredient causing drowsiness. The standard green NyQuil most people take does not contain any alcohol.
Side Effects of NyQuil
NyQuil can cause a variety of side effects, including:
Drowsiness
Drowsiness is the most common side effect of NyQuil due to the antihistamine doxylamine succinate. Doxylamine crosses the blood-brain barrier and binds to H1 receptor sites in the brain, which has a sedative effect. The drowsiness normally sets in within 30 minutes to 1 hour after taking NyQuil and can last up to 4-6 hours.
Impaired Cognitive and Motor Function
Because doxylamine succinate causes drowsiness, NyQuil can also impair cognitive functions like reaction time, coordination, concentration and decision-making. It is not recommended to drive, operate heavy machinery or perform tasks that require alertness after taking NyQuil until the drowsiness wears off. The sedating effects can cause motor incoordination, slow reflexes and delayed reaction time.
Headache
Some people may experience headaches after taking NyQuil, likely due to ingredients like acetaminophen and doxylamine succinate. Headaches seem more common with use of DayQuil, the daytime non-drowsy formula of NyQuil.
Dry Mouth
NyQuil contains antihistamines like doxylamine that can reduce saliva production, leading to symptoms of dry mouth or throat, especially during sleep. This side effect may also contribute to the “hangover” feeling some people get the morning after taking NyQuil.
Nausea
Upset stomach or nausea can occur when taking NyQuil. This may be due to the combination of medications, or from taking it without food. Stomach discomfort is more likely if NyQuil is taken on an empty stomach.
Daytime Drowsiness
The sedating effects of the antihistamine in NyQuil can persist into the next day. Some people feel sluggish, drowsy or “hungover” the morning after taking NyQuil. This generally resolves within a few hours but can impact productivity and focus.
As with any medication, side effects depend on the individual and dosage taken. These are common, but not guaranteed side effects.
NyQuil Ingredients that Cause Sleepiness
The ingredients in NyQuil responsible for drowsiness and sleepiness are:
Doxylamine Succinate
Doxylamine succinate is the primary ingredient responsible for NyQuil’s sleep-inducing effects. Doxylamine is an antihistamine that crosses into the brain and binds to H1 receptor sites. This suppresses histamine activity and has strong sedative properties. Even small doses of doxylamine succinate can cause pronounced drowsiness. Each dose of NyQuil contains 6.25mg doxylamine succinate.
Alcohol (in some forms)
Some NyQuil products contain alcohol, including NyQuil Cough (10% alcohol), NyQuil Sinus (10% alcohol) and NyQuil Cold & Flu (12% alcohol). Alcohol has sedative properties and can enhance the drowsiness caused by doxylamine. The standard green-colored NyQuil does not contain alcohol.
Dextromethorphan (in high doses)
Dextromethorphan is a cough suppressant in NyQuil. In normal doses it does not significantly cause drowsiness. However, in very high doses dextromethorphan can have sedative effects and generate a “high” feeling. The dose in NyQuil is not high enough to cross the blood-brain barrier and cause this reaction.
Phenylephrine (in high doses)
The decongestant phenylephrine is not generally associated with drowsiness, although very high doses may potentially cause mild sedation in some people. The dose in NyQuil is low and unlikely to induce sleepiness.
So in summary, the antihistamine doxylamine succinate is by far the main ingredient inducing sleepiness from NyQuil. The alcohol content and high doses of dextromethorphan or phenylephrine may also contribute slightly.
Tips to Reduce Drowsiness from NyQuil
Here are some tips to help minimize drowsiness when taking NyQuil:
Take Earlier in Day
Take NyQuil as early in the evening as possible. This allows more time for the drowsy effects to wear off before bedtime.
Avoid Alcohol
Avoid alcohol when taking NyQuil, as it enhances sedation. Also avoid NyQuil products containing alcohol.
Stay Hydrated
Drink plenty of water, which may help reduce hangover-like symptoms the next day.
Consume Caffeine
Consuming a caffeinated beverage may offset some drowsiness, but monitor effects closely.
Use DayQuil
DayQuil is the non-drowsy formulation of NyQuil, without the antihistamine.
Lower Dose
Take a smaller dose of NyQuil if possible. Consult your doctor.
Nap Wisely
If very drowsy, take a short 20-30 minute nap to restore alertness. Avoid longer naps that can disrupt nighttime sleep.
Be cautious with driving or operating machinery after taking NyQuil until you know how it affects you. Get plenty of rest, stay hydrated and consult a doctor if the medication causes pronounced drowsiness.
Who Should Not Take NyQuil?
Certain people should use caution or avoid NyQuil altogether:
Children Under 12 Years Old
NyQuil should never be given to children under 12 years old. It contains multiple medications at doses appropriate for adults only.
People with Liver Disease
Individuals with severe liver disease should avoid NyQuil as it contains acetaminophen, which can potentially cause liver toxicity in impaired livers when taken frequently or at high doses.
People Taking Antidepressants
NyQuil contains doxylamine, which can potentially interact with certain antidepressants like MAOIs and cause dangerous effects.
People Taking Sleep Medications
Sedative effects may be compounded in those taking sleeping pills, anxiety medications or other drugs with sleep-inducing properties.
People with Breathing Issues
Individuals with COPD, sleep apnea or other respiratory conditions may experience exacerbated breathing problems from NyQuil’s sedative properties.
People with Prostate Issues
The decongestant phenylephrine may worsen symptoms in people with prostate enlargement, prostatitis or other urinary conditions.
People Taking Other Cold Medicines
To avoid overdose, you should not take NyQuil together with other drugs containing acetaminophen, antihistamines, decongestants or cough suppressants.
Consult your doctor before taking NyQuil if you have any medical conditions, take other medications or have experienced adverse effects from it in the past.
Is it safe to take NyQuil every night?
It is generally not recommended to take NyQuil on a regular nightly basis. Here are some concerns with frequent NyQuil use:
Drug Tolerance
With repeated nightly use, the sedative effects of NyQuil may become less pronounced over time as tolerance develops. You may need higher doses to get the same effects.
Psychological Dependence
Taking NyQuil routinely can lead some people to develop a psychological dependence, where they believe they need it to sleep. This may make it more difficult to sleep without the medication.
Daytime Drowsiness
The “hangover” feeling of drowsiness may persist into the next day and affect work or school performance and concentration.
Other Side Effects
Frequent use raises the risks of other side effects like headaches, nausea, stomach discomfort and dry mouth.
Acetaminophen Toxicity
Taking acetaminophen regularly, even at normal doses, can potentially lead to liver toxicity over time.
Masking Medical Conditions
Taking NyQuil frequently may cover up an undiagnosed sleep disorder or other medical issue causing sleep problems.
While occasional short-term use is generally fine, it’s best to avoid taking NyQuil daily for extended periods. Chronic problems sleeping should be addressed with your doctor. There are likely safer, non-drug options to improve your sleep habits.
Alternatives to Reduce Drowsiness from NyQuil
If you are trying to avoid the drowsy side effects of NyQuil, some alternatives include:
DayQuil
DayQuil relieves cold/flu symptoms without the antihistamine that causes drowsiness. It contains the same ingredients as NyQuil except for the doxylamine succinate.
Allergy Medications
Taking a non-drowsy antihistamine such as loratadine (Claritin) or cetirizine (Zyrtec) will treat allergy symptoms without sedation.
Analgesics
For fever and aches, take an analgesic like acetaminophen (Tylenol) or a nonsteroidal anti-inflammatory drug like ibuprofen (Advil) alone instead of NyQuil.
Cough Drops
Soothe a cough and sore throat with cough drops containing menthol, honey or glycerin instead of NyQuil’s cough suppressant dextromethorphan.
Nasal Saline Spray
Use a saline spray to thin mucus and provide nasal relief instead of a decongestant like phenylephrine.
Expectorants
An expectorant like guaifenesin (Mucinex) can help loosen chest congestion without drowsiness.
Honey
Honey can help suppress coughs and soothe sore throats without sedative side effects.
Discuss the best alternative cold symptom relievers for your situation with your pharmacist or doctor to avoid NyQuil’s sleepiness.
Conclusion
NyQuil is an effective nighttime cold and flu medication composed of acetaminophen, dextromethorphan, doxylamine succinate and phenylephrine. It provides relief for symptoms like fever, aches, cough, congestion, runny nose and sneezing. The antihistamine doxylamine succinate is responsible for NyQuil’s sleep-inducing effects by crossing into the brain and binding to H1 receptors. Some NyQuil products contain alcohol which can enhance sedation. Other ingredients like dextromethorphan may add to drowsiness in very high doses.
Side effects like excessive daytime drowsiness the next day can be minimized by taking NyQuil earlier in the evening, staying hydrated, using caffeine wisely or opting for the non-drowsy DayQuil formulation. Certain people like those with liver disease or breathing issues should avoid NyQuil. It is also not recommended for regular, repeated use at night due to concerns like rebound insomnia, acetaminophen toxicity or masking underlying medical conditions.
When used only occasionally for short-term relief, NyQuil is generally safe and effective. But frequent long-term use for chronic sleep issues is not advisable. Speak to your doctor if NyQuil causes pronounced grogginess that interferes with your daily productivity or sleep habits.
| NyQuil Product | Alcohol Content |
|---|---|
| Standard Green NyQuil | None |
| NyQuil Cough | 10% |
| NyQuil Sinus | 10% |
| NyQuil Cold & Flu | 12% |
