Effects of acepromazine maleate or morphine on tear production before, during, and after sevoflurane anesthesia in dogs.
OBJECTIVE
To investigate the effects of acepromazine maleate and morphine on aqueous tear production before, during, and after sevoflurane anesthesia in dogs.


METHODS
6 mixed-breed dogs.


METHODS
In a Latin square study design, dogs underwent i.m. administration of morphine (1 mg/kg), acepromazine (0.05 mg/kg), or saline (0.9% NaCl) solution (0.05 mL/kg), followed by induction and maintenance of anesthesia with sevoflurane for 30 minutes. The protocol was repeated until all dogs had received all treatments, with a minimum of 7 days between anesthetic episodes. Aqueous tear production was measured via Schirmer tear test I before treatment (baseline); before anesthetic induction; 5, 10, 20, and 30 minutes after anesthetic induction; immediately once dogs recovered from anesthesia; and 2 and 10 hours after recovery.


RESULTS
Aqueous tear production for all treatments was significantly lower 10, 20, and 30 minutes (but not 5 minutes) after anesthetic induction than at baseline, before anesthetic induction, at recovery, and 2 and 10 hours after recovery. Aqueous tear production was significantly higher after saline solution administration than after morphine administration at the preinduction measurement point and 2 hours after recovery. No other differences were detected among the 3 treatments.


CONCLUSIONS
Aqueous tear production after anesthesia did not differ significantly from baseline values after any treatment following 30 minutes of sevoflurane anesthesia, suggesting premedication with morphine or acepromazine does not contribute to a decrease in lacrimation in these circumstances.
Department of Small Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.
Meredith C
MC
Mouney
Peter J
PJ
Accola
Jeannette
J
Cremer
Molly K
MK
Shepard
Carolina
C
Rodriguez Guarin
Erik H
EH
Hofmeister
D000075:Acepromazine / Q000008:administration & dosage / Q000009:adverse effects* / Q000494:pharmacology; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000009:adverse effects* / Q000494:pharmacology; D000769:Anesthesia, Inhalation / Q000009:adverse effects / Q000662:veterinary*; D018685:Anesthetics, Inhalation / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D014150:Antipsychotic Agents / Q000008:administration & dosage / Q000009:adverse effects* / Q000494:pharmacology; D004285:Dogs; D007273:Injections, Intramuscular / Q000662:veterinary; D008738:Methyl Ethers / Q000008:administration & dosage / Q000494:pharmacology; D009020:Morphine / Q000008:administration & dosage / Q000009:adverse effects* / Q000494:pharmacology; D011229:Preanesthetic Medication / Q000009:adverse effects* / Q000662:veterinary; D000077149:Sevoflurane; D013666:Tears / Q000187:drug effects / Q000378:metabolism*
D000701:Analgesics, Opioid; D018685:Anesthetics, Inhalation; D014150:Antipsychotic Agents; D008738:Methyl Ethers; D000077149:Sevoflurane; D000075:Acepromazine; D009020:Morphine