Doxycycline
"Developed bronchial infection couple of days into a cold. Tried usual cold remedies, but was feeling worse. Got up enough strength to drive over to my primary physician who is also a pulmonary specialist. I wanted chest x-ray as I had double-pneumonia years ago, was hospitalized, very ill, so ill they brought priest in for my last rites. My physician prescribed 100 mgs doxycycline 2 x daily, told me to take it with food if I felt nauseous.  First 2 days I was ok; took it with 8 oz. water as directed, ate some bread with it, waited to eat my full meal, stayed off dairy. Third day nausea, dizziness began, head felt like vice grips were squeezing it. Into day 4 now, still same side effects, but med is breaking up and clearing out infection."