Merck Manual

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Analgesics, Sedatives, and Anesthetics Used in Reptiles

Analgesics, Sedatives, and Anesthetics Used in Reptiles


Dose and Route



1.5 mg/kg, IM, SC

10 mg/kg, IM, SC

Chelonians (red-eared sliders)

Lizards (bearded dragons)

Not analgesic for snakes. Causes pronounced respiratory depression in turtles.


0.5 mg/kg, IM, SC

Chelonians: appears to cause less respiratory depression than morphine


5 mg/kg/day, PO, SC;

10 mg/kg, PO, every 4 days

Chelonians (red-eared sliders); less respiratory depression than morphine


20 mg/kg, SC

Snakes (cornsnakes) at high doses. Not analgesic for bearded dragons or red-eared sliders. May cause respiratory depression, and high-dose volume may be impractical. May be able to partially antagonize opiate agonists like morphine.


0.2 mg/kg, IV, IM, SC, every 24–48 hr


10–40 mg/kg, IM

40–60 mg/kg, IM

Sedation, prolonged hangover effects

Deeper sedation but not sufficient for painful procedures and care in debilitated individuals

Ketamine 10 mg/kg, combined with medetomidine 0.1–0.2 mg/kg (or dexmedetomidine 0.05–0.1 mg/kg) and morphine 1.5 mg/kg or hydromorphone 0.5 mg/kg, IM (or 50% dose, IV)

Deep sedation/anesthesia in many chelonians. Reversed using atipamezole (0.5 mg/kg, IM) and, if necessary, naloxone (0.2 mg/kg, IM)


2 mg/kg, IM

Premedication, or can be given with ketamine to increase sedative effects or promote similar effects at lower ketamine doses.


0.05–0.1 mg/kg, IV or IM

Often used in combination with ketamine and opiates as a sedative to light anesthetic. Useful when IV access is difficult.


10 × mg dose of dexmedetomidine, IM

Used to reverse dexmedetomidine


3–12 mg/kg, IM

Tortoises, lizards, snakes. Low dose useful to facilitate intubation. Higher doses associated with prolonged recoveries.


3–10 mg/kg, IV, intraosseous

Low dose rate for larger reptiles. Subanesthetic doses produce variable short-term sedation.


5–10 mg/kg, IV

10–20 mg/kg, IM

Similar effects to those of propofol IV, but higher doses effective IM. Larger IM dose volumes may warrant dividing into two or more injections.



Routine gaseous agent; subanesthetic levels provide short-term sedation. Mask down or conscious (sedated) intubation possible in some species.



Very similar effects to those of isoflurane but recoveries appear to be faster. Preferred agent for critical or large reptiles.