bronchitis
"I have had what I originally thought might be pneumonia, then decided was bronchitis.  My doctor gave me one antibiotic which didn't kill much of 'the bug', so he put me on tetracycline 100mg twice a day.  I immediately had some nausea, which I never have.  Over the next three days I developed, and still have: esophagitis, dyspepsia (heart burn), diarrhea, unusual  headache, noticeable lack of appetite, and new onset lower back pain.  In all fairness I have several health issues, but these symptoms that l listed above are new, except for the last two, although this time the rate and severity of these symptoms are different.  The drug seems to work well, I have almost always seen good results in my patients, but the side effects suck."