How Long To Wait In-Between Doses Of NyQuil?

In our latest question and answer, the pharmacist discusses how long you need to wait in-between doses of NyQuil.


How long do you have to wait for in-between doses of NyQuil?

Asked by Craig On Aug 18, 2022

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Aug 18, 2022
Last updated Feb 23, 2024

Key points

  • Nyquil is recommended to be dosed every 4 to 6 hours, with a maximum of 4 doses per day.


Thanks for reaching out!

NyQuil is a combination ingredient product that is used to treat the symptoms of colds and the flu. How long the effects of NyQuil last varies by individual but generally lasts around four to six hours per dose.

Per the manufacturing labeling for NyQuil, it is important not to exceed 4 doses in a 24-hour period. Based on the duration of action of NyQuil, each dose should be separated by at least 6 hours.

Time To Wait Between NyQuil Doses

NyQuil contains the following ingredients:

  • Acetaminophen 650 mg (Pain reliever/fever reducer)
  • Dextromethorphan HBr 30 mg (Cough suppressant)
  • Doxylamine succinate 12.5 mg (Antihistamine)

Each ingredient in NyQuil has a duration of action of around 4 to 6 hours, although the sedative effects (which come from the sedating antihistamine doxylamine) have been known to last up to 8 hours in certain individuals. It is important to not take an additional dose of NyQuil if you are still feeling the sedating effects of the product. 

However, if the effects of your last dose of NyQuil have worn off, you are safe to take another dose as long as 6 hours have passed since your last dose. Waiting 6 hours between doses will ensure that you do not take more than the recommended maximum of 4 daily doses.

Final Words

Thanks again for your question!


  • Histamine-1 receptor antagonism for treatment of insomnia, JAPhA
  • NyQuil Manufacturer Website, Vicks

About the Pharmacist

Dr. Brian Staiger, PharmD

Dr. Brian has been practicing pharmacy for over 13 years and has wide-ranging experiences in many different areas of the profession. From retail, clinical, program development, and administrative responsibilities, he's your knowledgeable and go-to source for all your pharmacy and medication-related questions! Dr. Brian Staiger also has herbalist training and educational certificates in the field of medical ethnobotany. Feel free to send him an email at [email protected]! You can also connect with Dr. Brian Staiger on LinkedIn.

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