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I am allergic to penicillin can I take cephalexin

A member asked:
Dr. David Edelman
General Surgery 40 years experience
Probably should not: Cephalexin is related to penicillin and there is a chance of an allergic reaction. Many people who are allergic to penicillin can take Cephalexin saf... Read More
Created for people with ongoing healthcare needs but benefits everyone.
Dr. Ronald Krauser
A Verified Doctoranswered
Rheumatology 53 years experience
Yes: Unless you had an anaphylactic reaction to penicillin (major breathing problems) there is little risk to trying cephalexin.
Created for people with ongoing healthcare needs but benefits everyone.
A 39-year-old member asked:
Dr. Doanh Nguyen, md, faaaai
Allergy and Immunology 15 years experience
Yes: Cross reactivity between the two classes are low so Cephalexin is not contraindicated in penicillin allergy patients. You should have your prescribing... Read More
Created for people with ongoing healthcare needs but benefits everyone.
A 22-year-old female asked:
Dr. Martin Raff
Infectious Disease 57 years experience
Penicillin allergy: You have what is known as an immediate hypersensitivity reaction to penicillin derivatives and should never be given one, since this is life-threateni... Read More
Created for people with ongoing healthcare needs but benefits everyone.
A 21-year-old member asked:
Dr. Alex Martinez
Specializes in Allergy
Maybe: Penicillins (like amoxil) & cephalosporins (like keflex) are both beta-lactam antibiotics named because of their ringed chemical structure. Allergy to... Read More
Created for people with ongoing healthcare needs but benefits everyone.
A 42-year-old member asked:
Dr. Paul Carter
A Verified Doctoranswered
31 years experience
No: If you are truly allergic to penicillin, you should avoid all penicillin derivatives and the first generation cephalosporins. Keflex is a first gen. ... Read More
Created for people with ongoing healthcare needs but benefits everyone.
A 36-year-old member asked:
Dr. Jeffrey Rumbyrt
Allergy and Immunology 33 years experience
Yes: Cephalexin (keflex) is a first generation cephalosporin and a very close cousin to penicillin. Though it is not 100% true that all penicillin allergi... Read More
Created for people with ongoing healthcare needs but benefits everyone.
A 29-year-old female asked:
Dr. Eric Stansby
Emergency Medicine 27 years experience
Don't panic: Scarlet fever is an acute febrile illness, primarily affecting children, caused by group a beta-hemolytic streptococci. Clinical manifestations inclu... Read More
Created for people with ongoing healthcare needs but benefits everyone.
A 43-year-old female asked:
Dr. Larry Lutwick
Infectious Disease 50 years experience
Before it is given,: Some people who are penicillin allergic can have cross allergies to cephalosporins like keflex.
Created for people with ongoing healthcare needs but benefits everyone.
A 41-year-old member asked:
Dr. Robert Ramirez
Allergy and Immunology 19 years experience
No: There is indeed crossreactivity, but: -if you are allergic to cephalosporins like cephalexin, and have had penicillin with no problem in the past, mos... Read More
Created for people with ongoing healthcare needs but benefits everyone.
A 30-year-old female asked:
Dr. John Chiu
Allergy and Immunology 58 years experience
Mostly not: The incidence of cephalexin allergy in patients with penicillin allergy is in the single digit % and likely not much different from patient without a ... Read More
Created for people with ongoing healthcare needs but benefits everyone.