I'm allergic to bactrim (sulfamethoxazole and trimethoprim). now my neck has a rash and i'm very drowsy after taking doxycycline hyclate. could i be allergic to it also?

?: Bactrim (sulfamethoxazole and trimethoprim) and doxycycline don't cross react, meaning if you're allergic to one of them doesn't mean you are allergic to the other. Whether what you are currently experiencing is an allergic reaction to the doxycycline, maybe, if in doubt, just stop it, call your doctor or the doctor who prescribed it for evaluation, good luck

Not doxycycline: What is the reason for taking doxycycline? Allergy to this is very unusual. You are not describing a reaction to doxycycline. See your Dr.

Possibly: Bactrim (sulfamethoxazole and trimethoprim) and doxycycline are not related, although a person who is allergic to one drug is sometimes allergic to others not because the drugs are related, but because the person is allergic to many substances in general. What you are experiencing may or may not be a reaction to doxycyline, and I would recommend reporting it to the prescriber - particularly if you are experiencing fever too