title: The influence of pre-anaesthetic administration of buprenorphine on the anaesthetic effects of ketamine/medetomidine and pentobarbitone in rats and the consequences of repeated anaesthesia.
abstract: Rats received pentobarbitone (60, 48 and 36 mg/kg i.p.) or ketamine/medetomidine (75/100, 60/80 and 45/60 mg/microg/kg i.p.) alone, or one hour following buprenorphine (0.5 mg/kg s.c.). Animals were anaesthetized once per week for 6 weeks with one of three anaesthetic doses according to a randomized block design. In the pentobarbitone group, animals which received buprenorphine had longer sleep times (236 +/- 22 cf. 204 +/- 21 min) and longer durations of surgical anaesthesia (83 +/- 14 cf. 27 +/- 8 min) (P<0.01), these effects being potentiated with increasing anaesthetic doses (P<0.01). A greater degree of respiratory depression was found in animals that received buprenorphine (P<0.01) although this was judged clinically acceptable in all cases. Unexpectedly high mortality and a high incidence of anaesthetic complications (nine of 16 animals) in the ketamine/medetomidine group made statistical analysis of these data impossible. We conclude that for pentobarbitone, pre-anaesthetic administration of buprenorphine reduces the dose of anaesthetic required to produce surgical anaesthesia, in addition to the presumed benefits of pre-emptive analgesia. In view of the high mortality encountered, we advise caution when considering pre-anaesthetic use of opioids in combination with ketamine/medetomidine in rats.
authors.affiliation: Comparative Biology Centre, Medical School, University of Newcastle upon Tyne, UK.
authors.forename: J V
authors.initials: JV
authors.lastname: Roughan
authors.forename: O B
authors.initials: OB
authors.lastname: Ojeda
authors.forename: P A
authors.initials: PA
authors.lastname: Flecknell
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage*; D000758:Anesthesia; D000777:Anesthetics / Q000008:administration & dosage*; D000818:Animals; D002047:Buprenorphine / Q000008:administration & dosage*; D007649:Ketamine / Q000008:administration & dosage; D020926:Medetomidine / Q000008:administration & dosage; D010424:Pentobarbital / Q000008:administration & dosage; D011229:Preanesthetic Medication; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000701:Analgesics, Opioid; D000777:Anesthetics; D002047:Buprenorphine; D007649:Ketamine; D010424:Pentobarbital; D020926:Medetomidine