Both Tamiflu and Keflex (cephalexin) can safely be taken with orange juice or soda. There are no interactions reported.


In fact, there are no reported interactions with any type of food or drink with either Keflex or Tamiflu.


Food or fruit juice is sometimes recommended with both. If either isn't well tolerated or causing nausea, food may help alleviate symptoms.


Tamiflu (Oseltamivir)

Tamiflu (Oseltamivir) is an oral antiviral medication that is classified as a 'neuraminidase inhibitor'. It is indicated for both the treatment and prevention of the flu (i.e. influenza virus).


Data indicates that Tamiflu is most effective when started as soon as symptoms of the flu appear. The Centers for Disease Control and Prevention (CDC) states that Tamiflu therapy is most effective when started within 48 hours of illness onset. However, in certain high risk populations, it can be started later than 48 hours and still have benefit. 


Tamiflu is available in both a capsule form and a liquid form and is generally well tolerated but can cause the following side effects:

  • Headache
  • Nausea
  • Vomitting
  • Diarrhea
  • Confusion
  • Dizziness
  • Nightmares


The most common side effects of Tamiflu are GI related and may be helped if given with food.


Keflex (Cephalexin)

Keflex (cephalexin) is a 'first generation' cephalosporin antibiotic, which are chemically related to penicillins but have a broader antibacterial spectrum. Keflex is used for a wide range of bacterial infections but is most commonly used to treat respiratory and skin infections.


Keflex is generally well tolerated with GI side effects being the most common.


Taking Tamiflu With Keflex

Taking Tamiflu with Keflex is safe and there is no interaction between the medications. Using both together however, may increase the risk of GI side effects such as nausea and diarrhea.