Long-acting injectable methadone (methadone-fluconazole) provides safe and effective postoperative analgesia in a randomized clinical trial for dogs undergoing soft tissue surgery.

OBJECTIVE: To assess the pharmacokinetics, clinical efficacy, and adverse effects of injectable methadone with the pharmacokinetic enhancer fluconazole (methadone-fluconazole), compared with the standard formulation of injectable methadone, in dogs after ovariohysterectomy. We hypothesized that 2 doses of methadone-fluconazole would provide 24 hours of postoperative analgesia. ANIMALS: 3 purpose-bred dogs (pharmacokinetic preliminary study) and 42 female dogs from local shelters (clinical trial) were included. PROCEDURES: Pharmacokinetics were preliminarily determined. Clinical trial client-owned dogs were blocked by body weight into treatment groups: standard methadone group (methadone standard formulation, 0.5 mg/kg, SC, q 4 h; n = 20) or methadone-fluconazole group (0.5 mg/kg methadone with 2.5 mg/kg fluconazole, SC, repeated once at 6 h; n = 22). All dogs also received acepromazine, propofol, and isoflurane. Surgeries were performed by experienced surgeons, and dogs were monitored perioperatively using the Glasgow Composite Measure Pain Scale-Short Form (CMPS-SF) and sedation scales. Evaluators were masked to treatment. RESULTS: Findings from pharmacokinetic preliminary studies supported that 2 doses of methadone-fluconazole provide 24 hours of drug exposure. The clinical trial had no significant differences in treatment failures or postoperative CMPS-SF scores between treatments. One dog (methadone-fluconazole group) had CMPS-SF > 6 and received rescue analgesia. All dogs had moderate sedation or less by 1 hour (methadone-fluconazole group) or 4 hours (standard methadone group) postoperatively. Sedation was completely resolved in all dogs the day after surgery. CLINICAL RELEVANCE: Methadone-fluconazole with twice-daily administration was well tolerated and provided effective postoperative analgesia for dogs undergoing ovariohysterectomy. Clinical compliance and postoperative pain control may improve with an effective twice-daily formulation.

Evaluation of Contamination of Multiuse Suture Cassettes in an HQHVSN Environment.

Historically, it has been thought that suture cassettes become contaminated by bacteria through multiuse. However, High-Quality, High-Volume Spay/Neuter (HQHVSN) veterinarians have been using them for years without issue because of their significantly lower cost. The objective of this study was to determine if absorbable suture cassettes are contaminated through multiuse in an HQHVSN environment. A total of 101 suture samples from suture cassettes were collected from 25 HQHVSN clinics or shelters. The suture samples were placed in an enrichment broth tube and aerobic and anaerobic culture with microbe ID were performed. A total of 17/101 samples were positive for microbial growth, with 11/25 clinics having at least one positive sample. Based on these results, there is a significant risk to using suture cassettes that must be balanced against cost savings. Although HQHVSN veterinarians do not report an increase in infection using suture cassettes, based on the results of this study, there is likely contaminated suture being used during sterilization surgeries at these surgery sites.