Interaction of Fluoroquinolones and Certain Ionophores in Broilers: Effect on Blood Levels and Hepatic Cytochrome P450 Monooxygenase Activity

The concomitant administration to broilers of ionophore coccidiostats and certain chemotherapeutic agents may cause deleterious interactions, with toxicosis and death as possible sequelae. In this study, co-administration of the ionophore monensin was not shown to alter blood levels of enrofloxacin or norfloxacin. In addition, exposure to lasalocid was not shown to change blood levels of enrofloxacin. However, norfloxacin + lasalocid co-administration induced aminopyrine N-demethylase (AD) activity by day 5 after the last administration of norfloxacin, and induced a rise of norfloxacin levels in the blood. This rise of blood norfloxacin levels after co-administration of norfloxacin + lasalocid implies that lower levels of norfloxacin could be administered in birds also receiving lasalocid.