Objective—To evaluate the efficacy of a single injection
of a sustained-release formulation of moxidectin
in preventing heartworm (Dirofilaria immitis) infection
for 12 months in dogs.
Animals—14 healthy dogs.
Procedure—Group A (nontreated control dogs; n = 6)
received sterile vehicle administered SC, and group B
(treated dogs; n = 6) received a sustained-release formulation
of moxidectin administered SC. All dogs
were housed in a heartworm-endemic area for 11.5
months, and heartworm antigen and modified Knott
tests were performed monthly. All dogs (including 2
additional control dogs [group C]) were then inoculated
with infective-stage larvae (L3) of D immitis, and
4.5 months later, all dogs were euthanatized and postmortem
examinations were performed. Adult D immitis
were counted and measured, and their age was
Results—All dogs in groups A and C were infected
with young (4- to 4.5-month old) adult male and
female D immitis. No dogs in group B were infected
Conclusions and Clinical Relevance—The age of
heartworms recovered suggests that infection was
the result of experimental inoculation and not natural
exposure to mosquitoes during the 11.5-month period
the dogs resided in a heartworm-endemic area. A single
SC injection of a sustained-release formulation of
moxidectin was effective in providing protection
against heartworm infection after 12 months in dogs.
This formulation is a convenient method of heartworm
prophylaxis that could eliminate the problem of
poor owner compliance. (Am J Vet Res 2004;
Objective—To compare the perioperative analgesic effect between methadone and butorphanol in cats.
Design—Randomized controlled clinical trial.
Animals—22 healthy female domestic cats.
Procedures—Cats admitted for ovariohysterectomy were allocated to a butorphanol group (n = 10) or methadone group (12) and premedicated with butorphanol (0.4 mg/kg [0.18 mg/lb], SC) or methadone (0.6 mg/kg [0.27 mg/lb], SC), respectively, in combination with acepromazine (0.02 mg/kg [0.01 mg/lb], SC). Anesthesia was induced with propofol (IV) and maintained with isoflurane in oxygen. A multidimensional composite scale was used to conduct pain assessments prior to premedication and 5, 20, 60, 120, 180, 240, 300, and 360 minutes after extubation or until rescue analgesia was given. Groups were compared to evaluate isoflurane requirement, propofol requirement, pain scores, and requirement for rescue analgesia.
Results—Propofol and isoflurane requirements and preoperative pain scores were not different between groups. During recovery, dysphoria prevented pain evaluation at 5 minutes. Pain scores at 20 minutes were significantly lower in the methadone group, and 6 of 10 cats in the butorphanol group received rescue analgesia, making subsequent pain score comparisons inapplicable. After 6 hours, only 3 of 12 cats in the methadone group had received rescue analgesia.
Conclusions and Clinical Relevance—In the present study, methadone appeared to be a better postoperative analgesic than butorphanol and provided effective analgesia for 6 hours following ovariohysterectomy in most cats. (J Am Vet Med Assoc 2013;243:844–850)
Animals—39 healthy female cats (10 in phase 1 and 29 in phase 2).
Procedures—Cats admitted for ovariohysterectomy received buprenorphine (4 in phase 1; 14 in phase 2) or butorphanol (6 in phase 1; 15 in phase 2). In phase 1, cats were premedicated with buprenorphine (0.02 mg/kg [0.009 mg/lb], IM) or butorphanol (0.4 mg/kg [0.18 mg/lb], IM), in combination with medetomidine. Anesthesia was induced with propofol (IV) and maintained with isoflurane in oxygen. After extubation, medetomidine was antagonized with atipamezole. A validated multidimensional composite scale was used to assess signs of pain after surgery starting 20 minutes after extubation and continuing for up to 360 minutes, and pain score comparisons were made between the 2 groups. Phase 2 proceeded similar to phase 1 with the following addition: during wound closure, cats from the butorphanol and buprenorphine groups received butorphanol (0.4 mg/kg, IM) or buprenorphine (0.02 mg/kg, IM), respectively.
Results—Phase 1 of the study was stopped after 10 cats were ovariohysterectomized because 9 of 10 cats required rescue analgesia at the first evaluation. In phase 2, at the first pain evaluation, pain scores from the buprenorphine group were lower, and all cats from the butorphanol group required rescue analgesia. None of the cats from the buprenorphine group required rescue analgesia at any time.
Conclusions and Clinical Relevance—Buprenorphine (0.02 mg/kg, IM) given before surgery and during wound closure provided adequate analgesia for 6 hours following ovariohysterectomy in cats, whereas butorphanol did not.