May interfere GI absorption & lowered systemic levels w/ antacid containing Ca, Mg or Al, as well as sucralfate, didanosine, metal cations eg, Fe & multivit prep w/ Zn or any products containing these components. Additive effects on QT interval prolongation w/ class IA (eg, quinidine, procainamide) or III (eg, amiodarone, sotalol) antiarrhythmic agents; antidepressants (eg, fluoxetine, imipramine); fluconazole. Disturbance of blood glucose eg, hyperglycemia, hypoglycemia w/ antidiabetic agents. Increased AUC of ciclosporin & tacrolimus. Increased risk of tendon rupture w/ corticosteroids particularly in elderly. Increased CNS stimulation & convulsive seizures w/ NSAIDs. Increased AUC & t½
w/ probenecid & cimetidine. Prolonged elimination t½
, elevated serum levels & subsequent increased AR of theophylline. Enhanced effects of warfarin.