Plasma disposition of paracetamol on co-administration with levofloxacin in cross bred calves

Plasma levels and disposition of paracetamol were determined in cross-bred calves after single intramuscular administration of 50 mg.kg(-1) followed by intravenous injection Of levofloxacin (4 mg.kg(-1)). The concentration of paracetamol in plasma was estimated spectrophotometrically. The minimum therapeutic plasma drug concentration was maintained up to 6 h of administration. Rapid absorption and moderate tissue distribution were evident by the small value of absorption half-life (0.31 +/- 0.03 h) and Vd(area) (0.62 +/- 0.04 L. kg(-1)). The AUC, t(1/2 beta),CIB and MRT were 312.9 +/- 15.8 mu g.ml(-1) h, 2.65 +/- 0.08 h, 162.0 +/- 8.62 ml.kg(-1) h(-1) and 4.09 +/- 0.11 h, respectively. A suitable intramuscular dosage regimen of paracetamol was calculated to be 55 mg.kg(-1) followed by 45 mg.kg(-1) at 6 h intervals when prescribed with levofloxacin in calves. The values of t(1/2)beta. AUC, Vd(area), CIB and dosage regimen were different from the corresponding values of these parameters reported after administration of paracetamol alone in calves. The present study revealed that disposition of paracetamol was altered by Concurrent administration of levofloxacin in calves.