VETINUITY
Alfaxalone induction is about 1-3 mg/kg IV to effect in premedicated dogs and 2-5 mg/kg IV to effect in premedicated cats, given slowly, with higher doses only in unpremedicated patients.
Alfaxalone 10 mg/mL. Doses assume premedication; titrate to effect.
The Vetinuity alfaxalone dose table induces premedicated dogs with about 1-3 mg/kg IV and premedicated cats with about 2-5 mg/kg IV, each given slowly over roughly 60 seconds until intubation is possible, with top-ups of about 0.5 mg/kg for short procedures. The Vetinuity alfaxalone dose calculator above shows the milligrams and millilitres of 10 mg/mL solution for your patient.
| Indication | Dog | Cat | Route and frequency |
|---|---|---|---|
| Induction after premedication | 1-3 mg/kg | 2-5 mg/kg | IV over about 60 s, to effect |
| Induction without premedication | Up to the label maximum; check the label | Up to the label maximum; check the label | IV, to effect |
| Maintenance by intermittent bolus | 0.5-1 mg/kg | 0.5-1 mg/kg | IV when the plane lightens |
| Sedation, intramuscular (extra-label in the US) | Not typical | 1-2 mg/kg combined with an opioid | IM |
Alfaxalone is a neuroactive steroid that acts at the GABA-A receptor. At clinical induction doses it keeps blood pressure and heart rate steadier than propofol in many patients, but it still causes dose-dependent respiratory depression, with post-induction apnea the most common problem. Muir and colleagues gave cats clinical and supraclinical doses and found the cardiorespiratory depression scaled with dose. Inject slowly, watch the chest, and be ready to ventilate.
Because cats are spared the red cell oxidative injury seen with repeated propofol, alfaxalone is a common pick for cats that need anesthesia several days running, such as radiation therapy or repeated bandage changes. The IM route in cats, mixed with an opioid such as methadone, is used to sedate fractious cats; the volume is large, so split it between sites. Alfaxalone is also used for cesarean induction because of its short context-sensitive duration; see the cesarean anesthesia page.
There is no analgesia. Recovery quality depends on premedication and a quiet environment. Multidose vials contain preservatives with a limited in-use life; follow the label. Alfaxalone is Schedule IV in the US.
Vetinuity, the clinical assistant built by emergency vet Brian Toncray, DVM, keeps this page next to propofol and the co-induction drug diazepam, and to the blocked cat page, where induction choice matters in a hyperkalemic cat.
Propofol induction is 2-4 mg/kg IV to effect in premedicated dogs (up to 6 mg/kg unpremedicated) and 2-6 mg/kg IV in cats, with a 0.1-0.4 mg/kg/min CRI for maintenance or refractory seizures.
Randomized trials comparing alfaxalone with propofol for canine cesarean induction: better neonatal Apgar scores with alfaxalone, similar puppy survival.
For seizures, diazepam is dosed at 0.5 mg/kg IV in dogs and cats (repeatable up to 3 times), 0.5-2 mg/kg per rectum in dogs, or 0.1-0.5 mg/kg/h as a CRI; oral diazepam is avoided in cats.
Methadone is dosed at 0.2-0.5 mg/kg IV, IM or SC every 4-6 hours in dogs and 0.2-0.3 mg/kg IV or IM every 4-6 hours in cats, and rarely causes vomiting.
Vetinuity's blocked-cat table: calcium gluconate 10% at 50-100 mg/kg IV over 10-20 min protects the heart, then regular insulin 0.5 U/kg with dextrose moves potassium into cells.
Rough recoveries with paddling, tremors and sensitivity to noise are described, mainly in patients without premedication or when recovered in a busy, bright area. Good premedication and a quiet recovery reduce them.
It avoids the oxidative red cell injury linked to repeated propofol in cats, which makes it a common choice for cats anesthetized on several days. Both depress breathing in a dose-dependent way.
Vetinuity explains clinical options with journal citations.
The veterinarian diagnoses and prescribes.