Sulfa danger?

December 26, 2008 9:15 AM

I'm allergic to sulfa drugs (specifically known to be allergic to Septra). My boyfriend's taking Bactrim, a sulfa drug. Could I have an allergic reaction from kissing him or coming into contact with his sweat? Could sleeping next to him be dangerous?
posted by anonymous to health & fitness (4 comments total)

I am also allergic to multiple sulfa drugs, including Bactrim, and have never had a problem when my husband was taking them. How allergic are you? I get itchy rashes from sulfa drugs.

Also, this can be cleared up pretty easily by just asking your or his doctor.
posted by gudrun at 9:45 AM on December 26, 2008

Some antibiotics are secreted into sweat glands or salivary glands. Rifampin (not a sulfa drug) is notable because it is secreted into the lacrimal glands, meaning that you can cry red tears.

As for Bactrim (TMP-SMX, trimethoprim/sulfmethoxazole), it is secreted into saliva, but later after dosing, and only at about 10% of the serum concentration (on the order of micrograms per milliliter of saliva). I think, unless your boyfriend drools copious amounts directly into your mouth during kissing, you're probably safe. I think you're definitely safe with regard to sleeping next to him, unless of course, he's melting into a pool of sweat and drool that you're eagerly lapping up. If that's the case, you may have a problem bigger than sulfa allergies.

See this paper for additional details ("Serum and saliva concentrations of sulfamethoxazole and trimethoprim in adults and children: relation between saliva concentrations and in vitro activity against nasopharyngeal pathogens," Scandinavian Journal of Infectious Disease, 1983 ... available at your local Scandinavian medical library.)
posted by scblackman at 10:09 AM on December 26, 2008 [3 favorites]

It's really impossible to answer without knowing more details, but I've heard anecdotal evidence about "partner sweat"-induced anaphylaxia even. If you are really sensitive I wouldn't risk it. But, IANAD and YMMV, I'd probably sleep holding hands anyway. Good luck.
posted by keijo at 11:30 AM on December 26, 2008

perhaps this is obvious, but do NOT have sex without a condom. friend of mine would get horrible, horrible rashes when her husband was taking an antibiotic and they would forget.
posted by micawber at 6:11 PM on December 26, 2008