Hello. I've taken 4 500 mg pills of zithromax and got diarrhea soon after. I felt fine but then I took a dose of Keflex. I am allergic to penicillin and I think i may have started to have an allergic reaction to keflex as well. My throat felt uncomfortable and tight and I started having muscle spasms as well as other weird symptoms. I just stopped taking it after the first dose due to my concerns even though I'm supposed to take it twice daily in order to get rid of my boil which seems to come and go. I'm wondering if the single dose of keflex along with the pills of zithromax will be enough or should I go back to my doctor and try to get another prescription?