Effects of enflurane and isoflurane anesthesia on the pharmacokinetics of pancuronium in adult patients.
OBJECTIVE
To evaluate the effects of 1 MAC of enflurane or isoflurane anesthesia on the pharmacokinetics of pancuronium.


METHODS
Eighteen adult patients undergoing the elective plastic surgery were randomly divided equally into 3 groups, namely, Group 1 (control group), Group 2 (enflurane group) and Group 3 (isoflurane group). Anesthesia was maintained with thiopental and 67% N2O-O2 in Group 1, 1 MAC enflurane in Group 2 and 1 MAC isoflurane in Group 3. After administration of a bolus of pancuronium 100 micrograms/kg, an improved fluorimetric assay was used to determine the serum concentrations of pancuronium and the pharmacokinetic variables of pancuronium were calculated with a 3P87 program.


RESULTS
The disposition of pancuronium may be well described mathematically by a two-compartment open model. The results showed that in comparison with the control group, patients in Group 2 and Group 3 had a longer T1/2 beta and MRT. The patients in Group 2 had the slower K10 and lower CL than those in the control group. There were no significant differences among the three groups in T1/2 alpha, V1, V2, Vdss, V beta, K21, K12 and AUC.


CONCLUSIONS
During enflurane and isoflurane anesthesia, CL of pancuronium decreased, and T1/2 beta and MRT of pancuronium were prolonged in our patients, so duration of the effective plasma concentrations of pancuronium was much longer. As a result, the effects of enflurane and isoflurane of the pharmacokinetics of pancuronium may be part of reason why two drugs extended the duration of neuromuscular depression produced by pancuronium.
Xue
F
F
Department of Anesthesiology, Plastic Surgery Hospital, Chinese Academy of Medical Sciences, Beijing.
Sun
B
B
Zou
Q
Q
Luo
L
L
D000293:Adolescent; D000328:Adult; D000769:Anesthesia, Inhalation; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D004357:Drug Synergism; D004737:Enflurane / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007530:Isoflurane / Q000494:pharmacology*; D008297:Male; D003473:Neuromuscular Nondepolarizing Agents / Q000493:pharmacokinetics*; D010197:Pancuronium / Q000493:pharmacokinetics*; D013518:Surgery, Plastic
D018685:Anesthetics, Inhalation; D003473:Neuromuscular Nondepolarizing Agents; D004737:Enflurane; D007530:Isoflurane; D010197:Pancuronium