Is It Safe To Take Antibiotics With Tamiflu?

In our latest question and answer, the pharmacist discusses why the use of antibiotics and Tamiflu is generally considered safe.

Question

Is it safe to take antibiotics while taking Tamiflu? I have the flu but I’m on my fourth day of Tamiflu and have an awful earache. Specifically, I want to know about amoxicillin.

Asked by Mon On Nov 15, 2022

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Nov 15, 2022
Last updated Nov 20, 2022

Key points

  • There is no known drug interaction between Tamiflu and antibiotic medications. They can safely be used together.
  • Amoxicillin does not interact with Tamiflu. They are safe to combine.

Answer

Yes, it is safe to take antibiotics, including amoxicillin, with Tamiflu (oseltamivir). There are no known interactions between any antibiotic drug and Tamiflu and they can be used together if you have multiple infections that need to be treated.

It is important to remember that antibiotics aren't effective against the flu as it is a viral infection. Nevertheless, if you have a bacterial infection you are treating at the same time as the flu (such as an ear infection), there should be no issue using an antibiotic and Tamiflu at the same time.

How They Work

Antibiotics are used for bacterial infections and work by either killing bacteria directly (i.e. bacteriocidal) or by inhibiting their reproduction (i.e. bacteriostatic).

Tamiflu, on the other hand, is an antiviral medication, technically classified as a neuraminidase inhibitor.

It works by inhibiting the neuraminidase enzyme, which prevents the spread of the virus, and studies show that it has activity against both influenza (i.e. flu) A and B viruses.

Antibiotics And Tamiflu Are Safe Together

Since Tamiflu and antibiotics (regardless of their class) have different mechanisms of action and work on different microbial agents (viruses and bacteria respectively), they do not inhibit and decrease the effect of the other.

In addition, there are no known pharmacokinetic interactions between Tamiflu and antibiotic drugs.

A pharmacokinetic interaction refers to one drug potentially affecting any number of properties of another, including their:

  • Absorption
  • Distribution (in the body and various tissues)
  • Metabolism
  • Excretion

In fact, there are several published studies that show that there may actually be a benefit to using both Tamiflu and antibiotics in certain situations.

Tamiflu With Antibiotic Studies

One such study, published in the journal Clinical Infectious Diseases, found that Tamiflu reduced the risk of lower respiratory tract complications (e.g. respiratory failure, sepsis) in those taking antibiotics by 28%.

Another study evaluated the combined use of azithromycin, a macrolide antibiotic, and Tamiflu.

The study found that the combined use was likely responsible for providing an early resolution of several flu-related symptoms, such as fever and sore throat. The study did not find, however, any reduction in inflammatory markers that were being tested for more data was needed to make a firm conclusion on the benefits of the combination.

Most studies looking at the combined use of Tamiflu and antibiotics note that they are well tolerated. However, since both often cause gastrointestinal problems (e.g. nausea, diarrhea), there is a chance that these side effects could happen more often.

Tamiflu With Amoxicillin

Since you asked about amoxicillin specifically, I'll call it out here in its own section.

As mentioned, Tamiflu is safe to take with amoxicillin.

Amoxicillin is a penicillin-type antibiotic that is generally well tolerated but can cause nausea and other related gastrointestinal effects. Taking it with food helps to relieve some of these side effects.

Tamiflu Drug Interactions

As discussed above, Tamiflu does not interact with antibiotics and actually has very few drug interactions at all.

The only one the prescribing information states is with live flu vaccines, since Tamiflu may reduce our immune response to them. Inactivated flu vaccines (the most commonly used) are fine to use though.

Another potential interaction is with the drug probenecid.

Studies show that the coadministration of Tamiflu and probenecid can cause more than a two-fold increase in Tamiflu concentrations. Nevertheless, this interaction is thought to be minor due to the relative lack of side effects caused by Tamiflu. If anything, there may be a slightly increased risk of nausea and related gastrointestinal side effects.

Final Words

Overall, if you have been prescribed an antibiotic and are also taking Tamiflu, they are safe together.

They should be prescribed for different illnesses though since antibiotics only treat bacterial infections and Tamiflu is only indicated to treat the flu (it can also be used as a prophylaxis for flu infection).

Thanks for reaching out and I hope you found this helpful.

References

  • Action and resistance mechanisms of antibiotics: A guide for clinicians, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5672523/
  • Tamiflu, Genentech
  • Elsevier ClinicalKey: Tamiflu Monograph, ClinicalKey (Subscription Required)
  • Oseltamivir and Risk of Lower Respiratory Tract Complications in Patients With Flu Symptoms: A Meta-analysis of Eleven Randomized Clinical Trials, PubMed
  • Efficacy of Combination Therapy with Oseltamivir Phosphate and Azithromycin for Influenza: A Multicenter, Open-Label, Randomized Study, PubMed
  • Pharmacokinetics and Tolerability of Oseltamivir Combined with Probenecid, PubMed

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 Hello@HelloPharmacist.com! You can also connect with Dr. Brian Staiger on LinkedIn.

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