When it comes to reptile medicine, anaesthesia and analgesia remain areas where many general practitioners lack confidence — and understandably so. Reptiles differ significantly from mammals in physiology, behaviour, and drug metabolism, making pain assessment and safe anaesthesia particularly complex. In the webinar “Sleepy Dragons: Anaesthesia and Analgesia in Reptiles”, Nathalie Wissink-Argilaga, RCVS Recognised Specialist in Zoo and Wildlife Medicine, delivered an insightful, evidence-based update on best practices for safely anaesthetising and treating pain in reptiles.

🧠 Do Reptiles Feel Pain?

Yes — and it’s no longer a matter of debate. Nathalie opened by emphasising that reptiles have well-defined pain pathways, with nociceptors similar to those found in mammals. However, interpreting pain in reptiles remains challenging due to species-specific behaviours, many of which are poorly understood.

Veterinary professionals must learn to identify subtle signs of discomfort, such as:

• Changes in heart and respiratory rate

• Limping or reduced range of movement

• Altered skin colour, particularly in chameleons

• Decreased interaction with the environment

Client input is crucial — owners can often spot changes in behaviour that may not be evident during brief clinical exams.

🌡️ Why Temperature Matters

One of the key differences in reptile anaesthesia is their ectothermic nature. Drug absorption, distribution, metabolism, and excretion are highly temperature-dependent. For example:

• High temperatures accelerate pharmacokinetics

• Low temperatures slow down drug processes and recovery

This makes environmental control essential during anaesthesia and recovery. Without stable, appropriate temperatures, even the best protocol can fail.

💉 Routes of Administration & Portal Systems

Nathalie offered practical advice on how and where to administer drugs in reptiles:

• Subcutaneous (SC) is often preferred: less restraint, suitable for larger volumes.

• Oral is viable for drugs like tramadol, which shows good absorption.

• Avoid injecting hepatic-metabolised drugs (e.g., opioids, anaesthetics) into the caudal body due to hepatic portal effects — these may reduce efficacy or alter pharmacokinetics.

• In contrast, IV administration via the ventral tail vein in lizards bypasses first-pass metabolism and is generally safe.

💊 Analgesia: What Works?

Reptile analgesia still lacks the robust evidence base we have for mammals. However, the following were discussed as part of current best practice:

• Tramadol: well absorbed SC

• Morphine

• Meloxicam

• Lidocaine: Used for ring or line blocks (diluted 1:1 with saline)

Dosages and protocols are disclosed in detail during the webinar.

She noted that opioids are effective in most species except snakes, and respiratory depression is a key concern, requiring careful respiratory monitoring.

🛌 Anaesthesia Protocols

The session also covered pre-anaesthetic evaluation, which must include:

• Full husbandry review

• Behavioural assessment

• Establishing temperature, hydration, and nutritional status

Intravenous anaesthesia via the ventral coccygeal vein is a reliable route in lizards, as it does not trigger hepatic first-pass metabolism.

Preferred agents and protocols include:

• Midazolam + medetomidine

• Low-dose IV propofol — noted for its reliability and safety

Monitoring remains a challenge, and while traditional tools such as Doppler or ECG may be used, interpretation requires experience and species-specific knowledge.

🐉 Final Thoughts

Nathalie’s webinar is an excellent resource for any veterinarian looking to improve their understanding of reptile anaesthesia and analgesia. From temperature control to analgesic protocols, it’s clear that attention to detail and species-specific adaptation are essential for success.

Whether you work with reptiles regularly or only occasionally, this session will give you practical tools and protocols you can trust.

🎥 Watch the webinar on demand now via The Webinar Vet.