Due to renal transplant (Kidney) I have to be real careful of what types of antibiotics I take. I took my prescription to the pharmacy. The pharmacist at Walgreens stated it had a major drug interaction with my anti-rejection medication. After working with the doctor they prescribed Sulfameth. It worked wonders. I did feel some sadness and was alittle irritable but that outwayed taking the chance that the upper respirtory infection damaged my kidneys and increased my creatnine to where I would be back on dialysis. so a little discomfort for me helped maintain my way of life and that is living my life to fullest and not becoming or behaving like a victim.