Which drugs can be used to euthanize a rat? - briefly
Approved agents for humane rat euthanasia include injectable barbiturates such as pentobarbital (e.g., Euthasol) and, where permitted, inhaled carbon dioxide; veterinary‑approved combinations like ketamine‑xylazine may also be used under strict protocols. All methods must follow institutional animal care guidelines and precise dosage calculations.
Which drugs can be used to euthanize a rat? - in detail
Pharmaceutical agents approved for rat termination are limited to those that produce rapid loss of consciousness followed by cardiac arrest without distress. The most widely accepted options are:
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Sodium pentobarbital – a barbiturate administered intraperitoneally at 150 mg/kg for adults, 200 mg/kg for neonates. Provides deep anesthesia within seconds, leading to respiratory and cardiac failure. Commercial preparations (e.g., Euthasol) contain a buffering agent to reduce pain on injection.
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Isoflurane – a volatile anesthetic delivered via a calibrated chamber. Induction at 5 % isoflurane in oxygen for 2–3 minutes, then maintenance at 2–3 % until apnea. Requires proper scavenging to protect personnel.
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Carbon dioxide – a gas euthanasia method approved for rodents when delivered at a flow rate of 20–30 % of the chamber volume per minute. Gradual displacement of air prevents panic; however, AVMA recommends CO₂ only when other agents are unavailable because it may cause dyspnea.
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Ketamine‑xylazine mixture – used less frequently because it may not guarantee immediate cardiac arrest. Typical dose: ketamine 100 mg/kg and xylazine 10 mg/kg intraperitoneally. Must be followed by a secondary agent (e.g., pentobarbital) to ensure death.
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Propofol – administered intravenously at 50–100 mg/kg. Provides rapid unconsciousness; however, intravenous access in rats is technically demanding and not routinely recommended.
Key procedural elements:
- Pre‑euthanasia sedation – optional low‑dose inhalant (isoflurane) or injectable (midazolam 2 mg/kg) to reduce stress before the lethal agent.
- Verification of death – absence of heartbeat, respiration, and reflexes for at least 5 minutes. Use a stethoscope or pulse oximeter.
- Disposal – render carcasses unusable for consumption; follow institutional biosafety protocols. Liquid waste containing barbiturates must be collected in a labeled container and disposed of as hazardous waste.
- Safety – wear gloves, eye protection, and use a fume hood for volatile agents. Avoid accidental exposure to CO₂ or anesthetic gases.
Selection criteria depend on facility resources, animal size, and regulatory requirements. Sodium pentobarbital remains the gold standard due to its reliability, rapid action, and compliance with most animal welfare guidelines.