Can You Give Keflex (Cephalexin) With NyQuil?

In our latest question and answer, Dr. Brian Staiger discusses the combined use of Keflex (cephalexin) and NyQuil.


My son was prescribed Keflex for an ear infection. He is having a lot of trouble going to sleep. Is it okay to give him NyQuil too?

Asked by Marvin On Dec 20, 2022

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Dec 20, 2022
Last updated Jul 17, 2024

Key points

  • There is no known drug interaction between Keflex (cephalexin) and the drugs contained in NyQuil.


There is no known interaction between NyQuil and Keflex (cephalexin). They are considered safe to take together.

In fact, NyQuil is safe to take with the vast majority of antibiotics, certainly with most of the common ones you'd see used for an ear infection (e.g., amoxicillin, azithromycin, amoxicillin; clavulanic acid, Bactrim etc...).

I'm happy that you reached out to us since it's always a good idea to look into potential interactions between prescription medicine and over-the-counter products, especially ones like NyQuil like contain multiple ingredients.

Hopefully this answer has given you some peace of mind.

NyQuil Is A Multi-Drug Product

It is important to remember that NyQuil is a product that contains multiple drugs, so, when you consider interactions, you need to take all of the drugs contained in it into account.

There are a variety of NyQuil products on the market, with the two most commonly used being the 'original' NyQuil and NyQuil Severe.

The original NyQuil contains three drugs:

  • Acetaminophen (pain reliever)
  • Dextromethorphan (cough suppressant)
  • Doxylamine (sedating antihistamine.

NyQuil Severe adds in the expectorant guaifenesin.

All of the drugs in the original NyQuil and NyQuil Severe are safe to give with Keflex (cephalexin). It can certainly be a good choice for short-term use to help your son sleep at night.

Final Words

I will also say here, wrapping up, is that if it is just the pain associated with your son's ear infection that is keeping him up, simply giving him only an analgesic, like Tylenol, may help. He may not need all the other drugs contained in NyQuil.

Additionally, you should see Keflex start working in 3 to 4 days. If the ear infection doesn't seem to be getting better, be sure to speak with the doctor.

I wanted to thank you for reaching out and contacting us! We are always more than happy to help.


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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