Euthanasia of Cats: Standard Approach
Primary Method
Intravenous administration of sodium pentobarbital is the most common and preferred method for euthanizing cats in veterinary practice. 1
Standard Protocol
Intravenous Route (First-Line)
- IV injection of barbiturate euthanasia solution (typically sodium pentobarbital at 390 mg/mL) is the gold standard, providing rapid and humane death with minimal patient distress 1
- This route ensures consistent, predictable results with immediate loss of consciousness followed by cardiopulmonary arrest 1
- The venous system is the most commonly used injection site due to its reliability and speed of action 1
Alternative Routes When IV Access Is Difficult
Intrarenal injection is a highly effective alternative when venous access cannot be established:
- Requires prior anesthesia of the cat 2
- 6 mL of sodium pentobarbital (390 mg/mL) injected directly into the kidney 2
- 79% of cats achieve cardiopulmonary arrest within 1 minute 2
- 95% of cats show no observable reaction other than cardiopulmonary arrest 2
- Palpable kidney swelling during injection correlates with faster time to death (median 0 minutes vs 1 minute without swelling) 2
Intrahepatic injection is another acceptable alternative:
- 82% accuracy in reaching the intended target (liver, liver/peritoneal cavity, or peritoneal cavity) 3
- More accurate than intraperitoneal injection (42% accuracy) 3
- Minimal patient response when restraint is minimal and injection is rapid (9% response rate) 3
Intraperitoneal Route (Less Preferred)
- Lower accuracy (42% reach intended site) and higher excitement rates (25% show stage I-II anesthesia activities) 3
- Should be avoided when other routes are feasible 3
Critical Technical Considerations
Drug Selection
- Sodium pentobarbital-based euthanasia solutions are the barbiturate drugs in consistent use today 1
- Addition of saturated potassium chloride to pentobarbital dramatically enhances effectiveness 4
- Pentobarbital can be reliably detected postmortem in multiple tissues (heart, liver, spleen, skeletal muscle, blood, urine) for forensic confirmation 5
Common Pitfalls to Avoid
- Do not sedate with acepromazine before nitrogen gas euthanasia, as this delays the effects and prolongs time to death 4
- Ensure adequate flow rate if using nitrogen gas (though this is not the common approach) 4
- Avoid initial suturing of bite wounds if euthanasia is for rabies testing—maintain brain integrity for laboratory examination 6
Special Circumstances: Rabies-Related Euthanasia
When euthanizing cats for rabies testing:
- Euthanasia must be accomplished in a way that maintains the integrity of the brain so anatomical parts can be recognized by the laboratory 6
- Submit only the head or brain (including brain stem) to the laboratory 6
- Keep specimens under refrigeration (not frozen or chemically fixed) during storage and shipping 6
- Any stray or unwanted cat that bites a person may be euthanized immediately and the head submitted for rabies examination 6