May increase risk of tendinitis & tendon rupture especially in adults >60 yr, patients receiving concomitant corticosteroids, & kidney, heart or lung transplant recipients. Discontinue treatment if pain, swelling, inflammation, or rupture of a tendon; symptoms of peripheral neuropathy, C. difficile
-associated diarrhea & colitis; hypersensitivity reactions (eg, rash, jaundice); photosensitivity or phototoxicity (sunburn-like reaction, skin eruption) occurs. Avoid use in patients w/ known prolongation of QT interval, w/ uncorrected hypokalemia, & in those receiving class IA (eg, quinidine, procainamide) or III (eg, amiodarone, sotalol) antiarrhythmic agents; concomitant use w/ cisapride, erythromycin, anti-pyschotic agents, TCAs. Patients w/ any ongoing proarrhythmic conditions, including bradycardia & acute myocardial ischemia. Known or suspected CNS disorders (eg, severe cerebral arteriosclerosis, epilepsy) or other risk factors that predispose to seizures or lower threshold. Discontinue treatment in pregnant & lactating mothers. Childn & adolescent <18 yr. Elderly especially those receiving corticosteroids.