Alfaxalone

Suitability

• Recommendations:  Recommendations cover multimodal use alongside Medetomidine in ASA1 and 2 patients.

• Suitable patients: The protocols below apply to ASA 1 and 2 patients. 

• High-risk patients: Clinicians are encouraged to tailor their practices to suit the additional issues encountered in ASA 3 & 4 and address them throughout the peri-anaesthetic period. 

• Informed Consent: Clinicians must ensure clients understand and accept additional risks. 

Patient Preparation

• Induction Preparation: Rabbits benefit from premedication, IV access and preoxygenation before Alfaxan induction.

• Suitable Handling: Ensure rabbits are kept away from predator contact, smell and excessive noise

• Intubation: In clinical settings, animals are usually intubated, or a supraglottic device is placed to allow volatile agents to be employed for anaesthetic maintenance.

• Analgesia: Where painful procedures are anticipated, clinicians must employ suitable analgesia agents and monitor the patient for pain.

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Medetomidine Option 1  | Medetomidine and Alfaxalone IM (M-A Sedation).

1. Induce: Medetomidine: 0.25 mg/kg and Alfaxalone 3-5 mg/kg; Administer together, slow IM.

2. Preoxygenate: Place in an oxygen chamber as sedation commences (Approx 5 mins)

3. Intubation: Consider intubation and maintenance through the use of a volatile agent (e.g. Isoflurane) with supplementary oxygen. Intubation is recommended during all painful or significant procedures.

4. Reversal: Optional. *Reversal with Atipamezole (2.5 X Medetomidine dose = half Medetomidine volume)

 (Marsh et al., 2009)

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Medetomidine Option 2 | Medetomidine and Butorphanol together followed by Alfaxalone IV (M-Bt-A Anaesthesia).

1. Induce: Medetomidine 0.04 mg/kg + Butorphanol 0.4 mg/kg + Alfaxalone 2.5 mg/kg, together, slow IM

2. Preoxygenate: Place in an oxygen chamber as sedation commences (Approx 5 mins)

3. Induce: One sedation, analgesia, and preoxygenation (5 mins) have taken effect to induce with Alfaxalone at 3-5 mg/kg slow IV to effect (Range 1-10 mg/kg)

4. Intubation: Subsequent intubation and maintenance through the use of a volatile agent (e.g. Isoflurane) with supplementary oxygen is recommended for all painful or significant procedures.

5. Reversal: Optional. *Reversal with Atipamezole (2.5 X Medetomidine dose = half Medetomidine volume)

(Wei et al., 2022)

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Medetomidine Option 3 | Medetomidine and Morphine together IM followed by Alfaxalone IV (M-Mo-A Anaesthesia).

1. Premedicate: Medetomidine 0.2 mg/kg + Morphine 1 -2 mg/kg, together, IV or IM.

2. Preoxygenate: Place in an oxygen chamber as sedation commences (Approx 5 mins)

3. Induce: One sedation, analgesia and preoxygenation (5 mins) have taken effect to induce with Alfaxalone 3-5 mg/kg, slow IV to effect (Range 1-10 mg/kg)

4. Intubation: Subsequent intubation and maintenance through the use of a volatile agent (e.g. Isoflurane) with supplementary oxygen is recommended for all painful or significant procedures.

5. Reversal: Optional. *Reversal with Atipamezole (2.5 X Medetomidine dose = half Medetomidine volume)

Evidence Base: (Navarrete-Calvo et al.)

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Reversal | Atipamezole Reversal of Medetomidine

• IM Atipamezole at 2.5 X  Medetomidine Dose (often half the volume of medetomidine)  alongside ventilatory and thermal support.

• 0.25mg/kg IM per 0.1 mg/kg of previously administered Medetomidine

(Baumgartner et al., 2010; Botman et al., 2020; Grint and Murison, 2008; Hellebrekers et al., 1997; Kaartinen et al., 2007; Kim et al., 2004; Kirihara et al., 2019; Orr et al., 2005; Williams and Wyatt, 2007)