Is it ok to take Keflex if I am alergic to penicillin?

17 Sep 2011

Hey HW5,

I don't know for sure, but I think maybe Not. I'm pretty sure Keflex is a different drug from Penicillin, but I also think it is closely related. I read up on Keflex almost 10 years ago and I remember thinking it's like a super Penicillin. That was my non doctor understanding of Keflex. So before you take it ask as many pharmacists and docs as you can. And even if they all say yes it is ok to take, I say take very little to start. A very small dose will mean a small allergic reaction. The bigger the dose, the worse of a reaction you can have.

17 Sep 2011

Keflex is a cephalosporin drug and there have been instances of cross allergies between the two drugs. If you are allergic to penicillin it is usually best to avoid Keflex too.

18 Sep 2011

Hey HW5, Thor is right. It's like a cousin to penicillian. A lot of doctors will have you try it anyway. Both my husband & I are allergic to pennicillian (hives) & both to Keflex. I get a really bad itchy rash, & he is more intolerant as it makes him sick to his stomach. ...

18 Sep 2011

Penicillin is a "cillin" and Keflex is a cephalosporin. 10% of patients who are allergic to Penicillin will also have a reaction to Keflex.
I hope this helps...