1 doctor weighed in:

Can i take bactrim (sulfamethoxazole and trimethoprim) if I am allergic to penecillin?

1 doctor weighed in
Dr. Martin Raff
Internal Medicine - Infectious Disease

In brief: Yes

From the standpoint of cross-allergy there is none.
Two questions. What is the allergic reaction to pcn? (are you truly allergic). And then, since patients prone to true allergic reactions have a great chance of reacting to sulfonamides (like in bactrim), not because of cross-hypersensitivity, but because sulfa drugs have high frequency of allergic reactions. Discuss this with your doctor.

In brief: Yes

From the standpoint of cross-allergy there is none.
Two questions. What is the allergic reaction to pcn? (are you truly allergic). And then, since patients prone to true allergic reactions have a great chance of reacting to sulfonamides (like in bactrim), not because of cross-hypersensitivity, but because sulfa drugs have high frequency of allergic reactions. Discuss this with your doctor.
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