Can you overdose on Nyquil?

Medically reviewed by Carmen Pope, BPharm. Last updated on Feb 14, 2025.

Official Answer by Drugs.com

Yes, you can overdose on Nyquil if you take more than recommended, give a child more than is recommended, or you give Nyquil to a child who is under the age of 6 years.

Nyquil contains acetaminophen (relieves pain and fever), doxylamine (an antihistamine that will dry up nasal secretions but can cause drowsiness), and dextromethorphan (to stop you from coughing).

There are a lot of different formulations of Nyquil so you must check the product label or ask your pharmacist if you are unsure what the correct dosage of Nyquil is. Always carefully measure the dose using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose. Ask your pharmacist for a measuring spoon.

The usual recommended dosage of Nyquil liquid is:

Children aged less than 6 years: Not recommended, do not give Nyquil to a child under 6 years
Children aged 6 to 11 years: 15mL every 6 hours if needed.
Teenagers aged 12 years or older: 30mL every 6 hours if needed
Adults: 30 mL every 6 hours if needed.

Do not give Nyquil more often than every 6 hours and do not give more than 4 doses per day.

For NyQuil liquid caps the dosage is:

Teenagers aged 12 years or older: 2 capsules every 6 hours if needed
Adults: 2 capsules every 6 hours if needed.

Do not give Nyquil liquid caps more often than every 6 hours and do not give more than 4 doses per day.

What are the symptoms of overdose with Nyquil?

Because Nyquil contains 3 ingredients, acetaminophen, dextromethorphan, and doxylamine, taking more than recommended can exceed the recommended daily dose for any one of those ingredients.

Symptoms of Nyquil overdose may include:

Difficulty breathing
Dilated pupils or blurred vision
Dry mouth
Hallucinations
Have difficulty passing urine or not passing as much urine as usual for you
Hyperactivity
Insomnia
Excessive tiredness or sleepiness
Liver problems such as dark urine, feeling tired, poor appetite, abdominal (stomach) pain, light-colored stools, throwing up, or yellow skin or eyes
Seizures
Severe dizziness
Severe anxiety

A large Nyquil overdose may be potentially fatal.

References

Vicks Products. Online. Frequently asked questions (FAQs). Accessed Feb. 24, 2022 at https://vicks.com/en-us/safety-and-faqs/faqs/vicks-nyquil-faq
Vicks NyQuil Products. Online. Accessed Feb. 24, 2022 at https://vicks.com/en-us/shop-products/nyquil

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