Intramuscular Kinetics and Dosage Regimens for Pralidoxime in Buffalo Calves (Bubalus bubalis)

Abstract

The plasma levels, disposition kinetics and a dosage regimen for pralidoxime (2-PAM) were investigated in male buffalo calves following single intramuscular administration (15 or 30 mg/kg). The effects of 2-PAM on various blood enzymes were also determined. The absorption half-life, elimination half-life, apparent volume of distribution and total body clearance of 2-PAM were 1.08±0.19 h, 3.14–3.19 h, 0.83–1.01 L/kg and 184.9–252.1 ml/(kg h), respectively. At doses of 15 and 30 mg/kg body weight, a plasma concentration ≥4 μg/ml was maintained for up to 4 and 6 h, respectively. Pralidoxime significantly lowered the serum level of transferases, phosphatases and lactate dehydrogenase but did not influence the acetylcholinesterase and carboxylesterase enzymes. The most appropriate dosage regimen for 2-PAM in the treatment of organophosphate toxicity in buffaloes would be 25 mg/kg followed by 22 mg/kg at 8 h intervals.