Is It Safe To Take Reactine (cetirizine) with cephalexin?

In our latest question and answer, the pharmacist discusses whether or not there is a drug interaction between Reactine (cetirizine) and cephalexin.

Is It Safe To Take  Reactine (cetirizine) with cephalexin?
Jul 16, 2020

Spike asked

Can you take Reactine when you’re taking cephalexin?

At a glance

  • Reactine is an over the counter antihistamine. It is a brand name of cetirizine.
  • There are no known drug interactions between cetirizine and cephalexin.


Hi Spike and thank you for your great question. I always appreciate when my patients ask me to double check that their prescription medications are safe with their OTC drugs.

I wasn’t familiar with Reactine as it’s not a brand sold here in the United States, but from what I can find, most forms of it are the drug cetirizine. Please double check your box and make sure that is the active ingredient. If it’s not cetirizine, then please disregard anything written below.

Cetirizine (or by the brands Reactine or Zyrtec) is a “second generation” antihistamine. It works by binding to histamine receptors in the body so that histamine can’t bind to them. This helps to reduce the symptoms typically caused by allergies (e.g. sneezing, itchy and watery eyes, post-nasal drip etc...). It is generally well tolerated and lasts about 24 hours.

Cephalexin is a first generation cephalosporin. It is commonly used to treat a wide variety of bacterial infections, but most commonly used for skin or ear infections.

The good news is that there are no known drug interactions between these two medications. In fact, I’ve recommended cetirizine to patients picking up their cephalexin prescription. It’s perfectly safe to take these both together.

Thanks for reaching out to us and I hope this helps.

Ready for a more personal experience with your meds?