This page is an educational reference for veterinarians and veterinary students. It does not replace a thorough examination, clinical judgment, or the attending veterinarian's final decision. Doses are for adult animals, per kilogram; the amount and volume of each drug for a patient, and the doses for neonates and seniors, are calculated in the tool itself.
Step by step
per kilogram of body weight
1 Preanesthetic preparation Before the injection
Healthy animal: allow free access to water; withhold food for 4–6 hours before anesthesia.2
Animal under 8 weeks or under 2 kg: withhold food for no more than 1–2 hours, monitor blood glucose before, during and after induction, and schedule it as the first patient of the day.2
Animal with a history or risk of regurgitation: withhold food and water for 6–12 hours.2
Acepromazine has a ceiling effect: a dose above this range does not deepen sedation; it only prolongs the effect and increases the risk of hypotension.4,5
Brief apnea and hypotension at induction are very common: inject slowly, and have intubation equipment, oxygen and assisted ventilation ready.3,7
Prepare the syringe with the volume of the range, but you need not inject it all: inject slowly IV to effect, until the depth of anesthesia is enough for intubation.3,7
Give the induction dose over about 10–40 seconds; injecting very slowly may not produce enough depth.7
Start at the low end. After the first portion, allow time for the drug to act and assess the animal; if needed, give further portions in small increments. Do not make the first portion too small, because a very small dose may cause excitement.3,6
After acepromazine alone, dogs need about 4.5 mg/kg on average; an opioid in the premedication lowers this. Each animal's need may be much lower or higher than the average.7
If the animal is moderately sedated after premedication, expect the low end of the range.3
After acepromazine alone, cats need about 6 mg/kg on average, near the high end of the range; an opioid in the premedication lowers this. Each animal's need may be much lower or higher than the average.7
Effects of this drug
Produces rapid, short anesthesia with a rapid recovery.7
Its effect starts quickly and is short, so it is easy to give to effect, and it can be repeated during the same anesthetic.3
Depresses breathing and circulation in a dose-dependent way. Brief apnea and mild hypotension at induction are very common; rapid injection causes apnea, bradycardia and hypotension.3,7
It relaxes muscle more than ketamine and midazolam; paddling, muscle twitching or nystagmus are sometimes seen at induction.1,7
5 Intubation, oxygen and eye protection Immediately after induction
Place the endotracheal tube as soon as possible and give oxygen.3,7
If breathing stops or is weak, provide assisted ventilation with oxygen.1,7
Apply a corneal lubricant ointment or drops and repeat every 2–4 hours.3
In cats, the larynx goes into spasm when stimulated: before intubation, drip no more than 0.2 mL of 2% lidocaine without epinephrine onto the arytenoid cartilages from a 1 mL syringe without a needle, and wait 60–90 seconds with oxygen. A spray with a nozzle may damage the laryngeal mucosa.6
In cats, if laryngospasm occurs, stop, give oxygen and check the depth of anesthesia; wait 60–90 seconds before trying again. Laryngospasm usually resolves on its own.6
6 Anesthesia 5–10 minutes
A single dose of propofol provides about 5–10 minutes of anesthesia.1
For a few more minutes, inject one-third to one-half of the induction dose again, slowly, to effect.1,3
For a longer procedure, maintain anesthesia with an inhalant.1
In cats, do not continue propofol for more than 30 minutes; cats eliminate it more slowly, and longer use prolongs recovery.6,7
7 Recovery After anesthesia ends
Recovery from propofol is rapid: the animal wakes as the drug redistributes from the brain to other tissues.7
Acepromazine lasts 4–6 hours and has no reversal agent; monitor temperature and blood pressure.6,8,9
The percentage on each side is not a measurement but a qualitative grade from the sources: full 100, good 75, partial 50, low 25, none zero. It refers to the peak effect after induction, not the whole duration.
HypnosisLoss of consciousness — 100% (Full)
Propofol produces rapid, predictable, short anesthesia and is given to effect.1,7
Propofol and acepromazine provide no analgesia; without an opioid, this protocol is for painless procedures.4,7
Anesthetic drugs are not analgesics: if the procedure is painful, the animal will feel the pain after it wakes.4
Muscle relaxationRelaxed muscle tone — 75% (Good)
Propofol produces more muscle relaxation than ketamine and midazolam.1
Paddling, muscle twitching or nystagmus are sometimes seen at induction.7
Blood pressure: Usually falls
Acepromazine and propofol both lower blood pressure; hypotension at induction is common.3,5,7
Propofol ↓ Lowers: Lowers blood pressure in a dose-dependent way; rapid injection increases hypotension and bradycardia.3,7
Acepromazine ↓ Lowers: Dilates blood vessels and lowers blood pressure, especially at high doses or in hypovolemia.4,5,8
Before you start: contraindications
Contraindication Do not give propofol to an animal hypersensitive to propofol or to the components of its emulsion.7
Contraindication Do not give acepromazine to an animal with hypotension, dehydration or hypovolemia, and correct the dehydration before induction; propofol also lowers blood pressure.4,5,6,7
Contraindication Do not give acepromazine to a pregnant animal.5
Cautions and notes
Caution Propofol and acepromazine provide no analgesia: for surgery or any painful procedure, also choose an opioid.4,7
Caution If the premedication does not sedate enough, more propofol is needed, and cardiovascular and respiratory side effects increase.3
Caution Use caution in heart, lung, liver or kidney disease, hypovolemia, hypoproteinemia and hyperlipidemia, and in very thin, debilitated or senior animals; a lower dose may be enough.3,7
Caution Propofol contains no antimicrobial preservative: draw it up aseptically, use it immediately after opening, and discard the remainder. Do not use it if the emulsion stays separated after gentle shaking.7
Caution In sighthounds (such as Greyhounds), propofol is eliminated more slowly and recovery may be slightly longer.1,7
Caution Monitor body temperature and keep the animal warm.4,5
Caution Dogs with the MDR1 (ABCB1) mutation need a lower dose of acepromazine; how much lower is not known, and the plan's amounts do not account for it.3
Caution Boxers and brachycephalic breeds may faint (syncope); give a low dose.5
Caution Large breeds are more sensitive to acepromazine; give the lowest possible dose.5
Note Draw up acepromazine in a separate syringe. Do not mix propofol with another drug in one syringe; it is compatible only with dextrose or saline solutions.5,7
Note Chloramphenicol, ketoconazole and loperamide slow the elimination of propofol and prolong recovery.7
Caution In cats, repeated propofol anesthetics may lead to red cell damage (Heinz body anemia), anorexia, diarrhea and prolonged recovery; if the cat must be anesthetized again, an interval of more than 48 hours reduces this risk.7
Reversal and emergency drugs
AtropineBradycardia
Ampoule 0.5 mg in 1 mL; do not confuse it with the 10 mg/mL ampoule