NyQuil Liquid: Uses, Dosage, Side Effects, Precautions and Alternates

Quick overview

NyQuil Liquid is an over-the-counter combination cold and flu medicine containing acetaminophen, dextromethorphan, and doxylamine. It is used to relieve symptoms such as headache, fever, body aches, cough, runny nose, sneezing, and sore throat caused by colds, flu, or allergies. Some versions also contain a decongestant for stuffy nose and sinus pressure. It belongs to the upper respiratory combinations drug class.

What is NyQuil Liquid

NyQuil is an over-the-counter combination cold and flu medicine. It is a line of products that usually combine a pain reliever/fever reducer, a cough suppressant, and an antihistamine that causes drowsiness. Some versions also add a decongestant.

NyQuil Liquid uses

• Headache
• Fever
• Body aches
• Cough
• Runny nose
• Sneezing
• Sore throat caused by allergies, the common cold, or the flu
• Stuffy nose and sinus congestion or pressure (in versions with a decongestant)

Benefits of NyQuil Liquid

• Treats several cold and flu symptoms at once with a single dose
• May help you sleep better by easing coughing and other symptoms
• Available without a prescription
• Comes in liquid, capsule, and gelcap forms for convenient dosing

How NyQuil Liquid works

NyQuil combines three types of medicine that each work differently: one ingredient eases pain and lowers fever, another calms the brain's cough signal, and an antihistamine blocks a body chemical that causes sneezing, runny nose, and congestion while also making you sleepy.

NyQuil Liquid dosage

Use exactly as directed on the label, or as prescribed by your doctor, and do not use for longer than recommended since cough and cold medicine is usually taken only for a short time until symptoms clear up. Measure liquid medicine with a dose-measuring spoon or medicine cup instead of a household spoon, since household spoons aren't accurate. You can take it with or without food; if it upsets your stomach, try taking it with food. It can make you sleepy or dizzy, so avoid driving or tasks requiring alertness until you know how it affects you. Taking the smallest effective amount close to bedtime can help reduce daytime sleepiness. Always ask a doctor before giving a cough or cold medicine to a child. Stop using and contact your doctor if your sore throat lasts more than 2 days, or if you have fever, headache, rash, nausea, or vomiting.

Available forms and strengths

• Liquid (oral solution)
• LiquiCaps
• Gelcaps
• Capsules

Side effects of NyQuil Liquid

Common

• Drowsiness
• Dizziness
• Constipation
• Nausea
• Headaches
• Nervousness or agitation (usually only for kids)
• Dry mouth
• Blurry vision
• Sleep problems (insomnia)
• Upset stomach
• Diarrhea
• Dry eyes
• Trouble concentrating
• Mild skin rash
• Trouble urinating
• Restlessness

Serious

• Liver damage
• Higher risk of falls for older adults
• Misuse
• Serious skin reactions
• Excessive sleepiness or dizziness
• Serotonin syndrome
• Severe headache, seizure
• Fast, pounding, or uneven heartbeats
• Confusion, hallucinations, slow or shallow breathing
• Tremor, restless muscle movements
• Little or no urinating
• Flu symptoms, easy bruising, unusual bleeding, pale skin, weakness, feeling light-headed
• Signs of liver problems: nausea, upper stomach pain, itching, loss of appetite, dark urine, clay-colored stools, jaundice

Warnings and precautions

• Do not use this medicine if you have taken a type of antidepressant called an MAO inhibitor within the past 14 days, as this can cause a dangerous drug interaction. 
• Do not take more than the recommended amount, because an overdose of the acetaminophen in this product can damage your liver or cause death. In rare cases, the acetaminophen in this medicine can cause a severe skin reaction that can be fatal, even if you've taken acetaminophen before without problems.
•  Taking this medicine with other acetaminophen-containing products can lead to an accidental overdose, since acetaminophen is found in many other medicines. 
• This medicine is not safe for children under 4 years old and can cause serious, possibly fatal problems like a fast heart rate and seizures in young children. Combining this medicine with other drugs that cause drowsiness or slow breathing, such as opioids, sleeping pills, or anti-anxiety medicines, can worsen these effects and raise the risk of serious harm. 
• Older adults are often advised to avoid medicines with doxylamine because the risk of severe drowsiness and falls usually outweighs the benefit for this age group.
• It is not known whether this medicine will harm an unborn baby. Do not use cough and cold medicine without a doctor's advice if you are pregnant.
• This medicine may pass into breast milk and may harm a nursing baby, and antihistamines may also slow breast milk production. Do not use cough and cold medicine without a doctor's advice if you are breastfeeding.
• Ask a doctor or pharmacist before taking this medicine if you have kidney disease.
• Ask a doctor before taking medicine that contains acetaminophen if you have ever had liver disease, or if you drink more than 3 alcoholic beverages per day.
• Avoid drinking alcohol while taking this medicine, since it may increase the risk of liver damage from acetaminophen and can increase certain side effects.
• This medication may cause blurred vision and may impair your thinking or reactions, so be careful if you drive or do anything that requires you to be alert and able to see clearly.

Storage

• Store at 20–25°C.
• Keep the bottle tightly closed.
• Protect from heat and direct sunlight.
• Keep in a dry place.
• Keep out of reach of children.

When to see a doctor

• Get emergency medical help right away if you have signs of an allergic reaction, such as hives, difficulty breathing, or swelling of your face, lips, tongue, or throat.
• Stop using the medicine and call your doctor right away if you notice skin redness or a rash that spreads and causes blistering and peeling.
• Call your doctor right away if you have signs that could mean liver problems, such as nausea, upper stomach pain, itching, loss of appetite, dark urine, clay-colored stools, or yellowing of the skin or eyes.
• If you think you may have taken too much of this medicine, get emergency medical help or contact a poison control center, since an acetaminophen overdose can be fatal.
• Stop taking the medicine and call your doctor if you still have a sore throat after 2 days, or if you develop a fever, headache, rash, nausea, or vomiting.
• Seek medical help right away for symptoms of serotonin syndrome, such as a fast heart rate, sweating, muscle stiffness or spasms, high fever, and confusion.

Alternatives

• DayQuil
• Robitussin
• Coricidin