Anesthesia & Sedation

Alfaxalone

Neuroactive steroid IV anesthetic with rapid onset and a favorable cardiovascular profile, used for induction of general anesthesia (with or without an inhalant carrier) and as a TIVA maintenance CRI for short procedures. Does NOT provide analgesia, pair with an opioid or other analgesic for any painful procedure. Stock 10 mg/mL (Alfaxan®).

Stock: 10 mg/mL · Schedule IV · No analgesia

Titrate slowly to effect, never rapid bolus. Administer IV over ~60 seconds. Rapid administration causes apnea, occurred in 40% of unpremedicated dogs and 16% of cats in field studies. Intubation, O₂, and IPPV must be immediately available.
No analgesia. Alfaxalone provides no analgesic effect. Ensure adequate pain coverage for any painful procedure.

Patient

Weight

lb kg

Species

Dog Cat

Premedication

Premedicated None

CRI rate (mg/kg/hr)

Rate

Dog premedicated: 6–7 · Cat premedicated: 7–8 mg/kg/hr

Awaiting input

Enter a patient weight to see the result.

Reference

How it works

Alfaxalone (3α-hydroxy-5α-pregnane-11,20-dione) is a neuroactive steroid that potentiates GABA-A receptors to produce dose-dependent CNS depression and general anesthesia. It is formulated in 2-hydroxypropyl-beta-cyclodextrin (HPCD), unlike the discontinued Saffan® formulation, it does not cause histamine release.

Induction doses assume slow IV titration over ~60 seconds. Premedication reduces the induction dose by 10–50% depending on agent, always titrate to the individual patient's response rather than administering the full calculated dose upfront.

CRI dosing maintains plasma concentrations through a continuous infusion. A 3-step infusion regimen (higher initial rate stepped down over time) has been described as producing more stable concentrations in cats than a single fixed rate; adjust based on anesthetic depth.

IM use (extra-label, cats): Alfaxalone has been used IM in cats in combination with dexmedetomidine and an opioid. For these protocols, see the Kitty Magic (DKT) calculator or the reference notes in the result panel above.

Formula

All doses use the same relationship: dose × weight ÷ stock concentration = volume to draw.

Induction

$$\text{volume} = \frac{\text{dose}_{\text{mg/kg}} \times \text{weight}_{\text{kg}}}{\text{stock}_{\text{mg/mL}}}$$

Sources

Plumb DC. Plumb's Veterinary Drugs. Alfaxalone monograph. Induction and maintenance doses from the FDA-approved label (dogs and cats); CRI dosing from label and extra-label references cited in Plumb's. plumbs.com
DEA Schedule IV controlled substance (Alfaxan®). Record all use per applicable regulations. Do not use with other IV general anesthetic agents (eg, propofol) per label.