Administration of acepromazine maleate to 31 dogs with a history of seizures

Incidence of seizures associated with the use of acepromazine in dogs undergoing myelography

OBJECTIVE

To investigate the frequency of seizures associated with acepromazine administration when used as a premedicant with methadone for dogs undergoing myelography.

DESIGN

Retrospective clinical case study.

SETTING

University veterinary teaching hospital.

ANIMALS

Sixty-six dogs (mixed and pure breeds), aged between 4 months and 15 years, weighing between 3.5-61 kg. All animals were classified as ASA score I or II.

INTERVENTIONS

Forty-three animals were premedicated with methadone (0.1-0.5 mg/kg) and acepromazine (0.01-0.05 mg/kg) intramuscularly. Twenty-three animals were premedicated with methadone alone (0.1-0.5 mg/kg) intramuscularly. Anesthesia was induced with propofol intravenously and maintained with isoflurane delivered in 100% oxygen. All animals received a balanced isotonic crystalloid solution intravenously at a rate of 10 mL/kg/h. Blood pressure, end-tidal CO(2) , oxygen saturation, respiratory rate, and heart rate were monitored throughout anesthesia. Animals requiring surgery immediately following myelography were excluded from the study.

MEASUREMENTS AND MAIN RESULTS

The frequency of seizures was 14% (CI: 3.6-24.3%) and 13.0% (CI: 0.7-27%) in dogs that received methadone/acepromazine and methadone alone, respectively. There was no significant difference in the frequency of seizures between dogs receiving methadone/acepromazine or methadone alone (P = 1). Analysis of the association of site of injection of the contrast and the frequency of seizures in dogs receiving methadone/acepromazine showed no significant difference in the frequency of seizures following cervical injection (25%; CI: 0.5-24.5%) or lumbar injection (9.7%; CI: -0.7-20.1%).

CONCLUSIONS

The administration of acepromazine combined with methadone as a premedicant used with propofol and isoflurane anesthesia did not significantly increase the frequency of seizures following myelography compared to dogs who received methadone alone.

AAHA anesthesia guidelines for dogs and cats

Safe and effective anesthesia of dogs and cats rely on preanesthetic patient assessment and preparation. Patients should be premedicated with drugs that provide sedation and analgesia prior to anesthetic induction with drugs that allow endotracheal intubation. Maintenance is typically with a volatile anesthetic such as isoflurane or sevoflurane delivered via an endotracheal tube. In addition, local anesthetic nerve blocks; epidural administration of opioids; and constant rate infusions of lidocaine, ketamine, and opioids are useful to enhance analgesia. Cardiovascular, respiratory, and central nervous system functions are continuously monitored so that anesthetic depth can be modified as needed. Emergency drugs and equipment, as well as an action plan for their use, should be available throughout the perianesthetic period. Additionally, intravenous access and crystalloid or colloids are administered to maintain circulating blood volume. Someone trained in the detection of recovery abnormalities should monitor patients throughout recovery. Postoperatively attention is given to body temperature, level of sedation, and appropriate analgesia.

Abnormal motor activity during anaesthesia in a dog: a case report

Seizures or convulsions that occur during anaesthesia in veterinary patients are infrequently reported in the literature. Consequently, the incidence of such events is unknown. Several drugs commonly used in clinical veterinary anaesthesia have been shown to induce epileptiform activity in both human clinical patients and experimental candidates. The present case report describes convulsions in a four-year old male Bernese mountain dog during maintenance of anaesthesia with isoflurane after premedication with acepromazine and methadone followed by co-induction with propofol and ketamine. The dog had no history of previous convulsions. The use of several sedative and anaesthetic drugs makes it difficult to find one single causative pharmaceutical.