bronchitis
"The z pak cleared up my bronchitis right away.  However it almost instantly caused symptoms of  gastritis and pancreatis that made me very ill for five months.  I could eat very little but was rapidly losing weight.  My doctor found low liver and kidney enzymes and suggested futher tests.  A endoscopy, colonoscopy, ultrasound, several lab tests and $1700 later there was no diagnosis but after five months i gradually got better.  The next winter I got another cold that turned into bronchitis and was again prescribed a z-pak.  Almost immediately the same symptoms occurred and I was just as sick for another 5 months.  This time the connection was clear - Z-PAK."