Comparative Pharmacokinetics of Enrofloxacin in Healthy and Trypanosoma brucei-Infected Cattle in Benue State

Drug disposition is frequently altered in infectious disease states due to changes in protein binding, hepatic enzyme activity, renal perfusion, and tissue distribution. Trypanosoma brucei infection, which causes significant hepatic and systemic pathology in cattle, may substantially modify the pharmacokinetics of concurrently administered antibiotics. Enrofloxacin is a fluoroquinolone antibiotic commonly co-prescribed with trypanocidal drugs to prevent secondary bacterial infections during trypanosome treatment. This study compared the pharmacokinetic profile of enrofloxacin in healthy and naturally Trypanosoma brucei-infected Zebu cattle at farms in Benue State, North Central Nigeria. Twelve healthy and 12 infected cattle confirmed by PCR received a single intravenous enrofloxacin dose of 5 mg/kg. Serial blood samples were collected at 11 time points over 48 hours and plasma enrofloxacin was quantified by validated HPLC. A non-compartmental analysis was applied to generate pharmacokinetic parameters. In infected animals, the area under the curve was significantly higher at 28.4 microgram-hour per millilitre compared to 21.7 in healthy cattle, while clearance was significantly reduced. Volume of distribution did not differ significantly between groups. These alterations suggest impaired hepatic and renal clearance in infected animals. The AUC to MIC ratio, a key pharmacodynamic index for fluoroquinolones, exceeded the efficacy threshold of 125 in infected animals for most bacterial targets, suggesting dose adjustment may not be required. However, prolonged drug exposure heightens resistance selection risk. The study provides critical data for rational enrofloxacin dosing during trypanosomosis treatment in Nigerian cattle. Keywords: enrofloxacin, pharmacokinetics, trypanosomosis, cattle, Benue State.