Dextromethorphan With Tamiflu (Oseltamivir) And Azithromycin

There is no interaction between them.


I tested positive for the flu and I have been prescribed a Z-pack and Tamiflu. Today will be my last day taking both. I tried not to take NyQuil while on these medications, as I read that I should not take a cough suppressant. I have not been sleeping due to this terrible cough I have. I was wondering if I would be able to take DayQuil regularly at this point as it's been 5 days and my cough is as bad as day 1.

Asked by Nagi On Dec 03, 2018

Answered by
Medical Content Reviewed By PharmacistAnswers Staff

On Dec 03, 2018

Dextromethorphan, the cough suppressant in both DayQuil and NyQuil, is safe to take with the Z-Pack (azithromycin) and Tamiflu (oseltamivir). There are no known drug interactions.

For your situation, unless you have a contraindication to dextromethorphan, or your doctor has recommended against it, it is considered safe to use with either DayQuil or NyQuil.

Remember that NyQuil and DayQuil are combination ingredient products, and contain many of the same drugs. Therefore, you don't want to use them at the same time. Be sure to separate doses by at least 6 hours.

DayQuil contains the following ingredients:

  • Acetaminophen 325 mg
  • Dextromethorphan HBr 10 mg
  • Phenylephrine 5 mg
  • Guaifenesin 200 mg (only in DayQuil Severe)

NyQuil contains the following ingredients:

  • Acetaminophen 325 mg
  • Dextromethorphan HBr 15 mg
  • Doxylamine succinate 6.25 mg
  • Phenylephrine 10 mg (Only in NyQuil Severe)

Tamiflu is safe to take with most drugs, as it has few documented interactions. In fact, only two are well known:

  • Intranasal Influenza Vaccine: (Major)
  • Probenacid

Giving Tamiflu with a live flu vaccine (such as the intranasal one) may inhibit viral replication and reduce vaccine efficacy.

Co-administering probenacid and Tamiflu can raise Tamiflu concentrations in the body nearly two-fold. However, the prescribing information for Tamiflu states that the interaction is not clinically relevant, due to the safety margin of the drug and no dosage adjustment is needed.

The Z-Pack has far more interactions than Tamiflu, but is safe with dextromethorphan (and all the other ingredients in NyQuil/DayQuil).

As mentioned above, taking a cough suppressant should be fine with the medications you mentioned. If you have further questions, be sure to send us an email or leave a comment below so we can reply.

About the Pharmacist

Dr. Brian Staiger Pharm.D

Dr. Brian Staiger is a licensed pharmacist in New York State and the founder of He graduated from the University At Buffalo with a Doctor of Pharmacy degree in 2010. He has been featured in numerous publications including the Huffington Post as well as a variety of health and pharmacy-related blogs. Please feel free to reach out to him directly if you have any inquiries or want to connect! He's answered thousands of medication and pharmacy-related questions and he's ready to answer yours! Office: 716-389-3076

Recent Questions