Sue and Beth, my dr at Mayo said to stay away from zpaks, he retired, and the dr that replaced him said the same thing. There are other effective broad spectrum antibiotics that will work instead. Their reasoning being, like you said Sue, is they don't want you to become resistant to the zpa, (Azithromycin). It is considered a 'Big Gun' in the antibiotic field, and the Mayo docs believe it should be used as a last resort treatment up the road should you become resistant to all other antibiotics.