A 6-year old healthy Springer Spaniel comes into the hospital exhibiting signs of mild FAS and some signs of pain from his bilateral stifle OA. You need to sedate him for radiographs. The best protocol for sedation in this patient is:

• A. Acepromazine alone
• B. Benzodiazepine alone
• C. Alpha-2 agonist alone
• D. Alpha-2 agonist + opioid

Answer: (D)

For a fearful, stressed dog with osteoarthritis pain requiring radiographs, a multimodal approach that provides both sedation and analgesia is best. An alpha-2 agonist plus an opioid delivers reliable, short-term sedation while also addressing pain from the joints. The alpha-2 component gives calmness and some analgesia, and the opioid adds robust analgesia and further sedation; together they work synergistically, so you can use lower doses of each, improving safety and recoverability. This combination helps keep the patient still enough for good radiographs while preventing stress-related behaviors driven by pain, which a single agent often fails to manage.

Why the others aren’t ideal here: using an acepromazine alone provides sedation without analgesia and can cause hypotension, which isn’t ideal when pain and stress are present. a benzodiazepine alone offers anxiolysis and light sedation but no analgesia, so the dog may still experience pain-related distress during positioning. an alpha-2 agonist alone gives sedation and some analgesia but carries cardiovascular risks and may not provide enough analgesia for OA pain in a short procedure. The combination of an alpha-2 agonist with an opioid avoids these gaps by ensuring both comfort and calm throughout the radiographic exam.