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Jacksonville, FL
A male asked:

is doxycycline as effective as penicillin with syphilis i am allergic to pen.also how long does it take for the doxy to work am infectious while on it?

1 doctor answer3 doctors weighed in
Dr. Hunter Handsfield
Infectious Disease 53 years experience
Just as effective: Yes, doxycycline is just as effective as penicillin, but you must take all of the pills more or less on time. You're probably non-infectious after a few days, but best to avoid sex until after completing the entire 2 weeks of treatment.

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Last updated Aug 23, 2017
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