Not All Remedies Are Equal Re "A Cure That Can Be Worse Than the Illness" (Personal Health, Sept. 11): In 2005 a doctor prescribed Tequin (gatifloxacin) for a sinus infection. In almost no time I went from swimming a mile several times a week and riding a bicycle 40 or 50 miles to gasping for breath. A pulmonologist berated me for being a smoker, even though I had never smoked in my life. Finally my internist prescribed erythromycin, which worked like a charm. The following year, Bristol-Myers Squibb pulled Tequin from the market. Better testing and regulatory oversight would have spared me and thousands of others a lot of suffering. Marc Edelman Although fluoroquinolones have been shown to have disturbing side effects, some of the drugs they replaced were aminoglycosides and chloramphenicol. The former was known to cause renal failure in some patients, the latter aplastic anemia, both potentially life-threatening complications. Physicians know that all interventions (surgical and pharmacological) have risk-benefit considerations. Fluoroquinolones universally are not bad drugs. Lawrence Semel, M.D. Syracuse, N.Y. The writer is clinical professor of surgery, SUNY Upstate Medical University.