Naltrexone-induced pruritus in a dog with tail-chasing behavior

Area of Science:

• Veterinary Pharmacology
• Animal Behavior

Background:

• Naltrexone is an opioid antagonist explored for managing stereotypic behaviors in animals.
• In human medicine, it's used for opioid abuse treatment, with rare dermatologic side effects like alopecia and pruritus.

Observation:

• A dog with tail-chasing and self-mutilating behavior exhibited an intense, dose-related pruritic reaction to naltrexone.
• The dog experienced significant itching and skin irritation during naltrexone administration.

Findings:

• Naltrexone provided limited therapeutic benefit for the dog's stereotypic behaviors, reducing but not eliminating them.
• The observed pruritic reaction was more severe than the <1% incidence reported in human patients.

Implications:

• Naltrexone's efficacy in treating animal obsessive-compulsive disorders may be inconsistent.
• Significant side effects, such as severe pruritus, coupled with high cost, may limit naltrexone's clinical use in veterinary medicine.