"Dr. Leon. For months I experienced a persistent cough, particulary bad in the mornings. But it was so persistent it was driving me insane. I finally tried a Z-pack which did nothing, not to be deterred I got a 2 week supply of Doxycycline. It absolutely CURED my cough, which I thought I had to live with forever! Obviously I had been living for some time with a bacteria in my lungs?? Do you agree? How often can I take this miracle drug without it losing its effect. I feel like a new person. Doxycycline knocked it out, zithromycin did nothing? can i live on anti-biotics alone, as Christ chided is the New Testament? Praise Doxycycline! john harper"