Effects of a single paracetamol injection on the sevoflurane minimum alveolar concentration in dogs

This study aimed to determine the effect of a single injection of paracetamol on the sevoflurane minimum alveolar concentration (MAC) response to noxious mechanical stimulation. Seven healthy adult beagles were enrolled in a prospective, randomized, blinded, crossover experimental study. Anesthesia was induced with propofol [11.6 ± 2.4 mg/kg body weight (BW)] and maintained with sevoflurane. The MAC was determined before (MAC-1) and after (MAC-2) treatment with 15 mg/kg BW of intravenous (IV) paracetamol or saline over 15 minutes. Samples for plasma paracetamol determination were collected immediately after IV treatment administration and following MAC-2 determination (123 ± 27 minutes after starting paracetamol administration). The MAC-1 was similar between treatments (1.7% ± 0.4%). There were no differences between control and paracetamol groups at MAC-2 (2.0% ± 0.4% and 1.7% ± 0.5%, respectively; P = 0.285). Paracetamol plasma concentrations after paracetamol administration were 34.5 ± 9.9 μg/mL, decreasing at the end of the procedure (8.5 ± 4.2 μg/mL). In conclusion, 15 mg/kg BW of IV paracetamol did not significantly reduce sevoflurane MAC in healthy dogs.