Acepromazine premedication, induction with ketamine and diazepam
IM premedication, then brief anesthesia with diazepam and ketamine IV, each in its own syringe; for short procedures that do not need strong analgesia.1,2,3
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.4
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.4
Animal with a history or risk of regurgitation: withhold food and water for 6–12 hours.4
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.5,6
Ketamine provides poor visceral analgesia: on its own it is not suitable for visceral surgery (such as abdominal surgery); use it only with an opioid.7,12
Immediately after diazepam, inject from a separate syringe, slowly IV, to the desired effect.1,2,3
Start at the low end and increase toward the high end only if needed.2
Produces analgesia and amnesia. Somatic analgesia (skin, muscle, bone) is good, but visceral analgesia is poor; on its own it is not enough for major, very painful or visceral surgery.1,12
Raises heart rate, blood pressure and cardiac output. It usually depresses breathing less than other induction agents, but respiratory depression increases with the dose, and apnea has been reported, especially in cats.1,7
On its own it causes muscle rigidity, which is why it is given with diazepam.1,2
6 Intubation and eye protection Immediately after induction
Place the endotracheal tube as soon as possible; pharyngeal and laryngeal reflexes are partly preserved, but they do not protect the airway.1,2
The eyes stay open: apply a corneal lubricant ointment or drops and repeat every 2–4 hours.1,2
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.8
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.8
7 Anesthesia 10–20 minutes
A single dose of diazepam and ketamine provides about 10–20 minutes of anesthesia.1,7
For a longer procedure, maintain anesthesia with an inhalant.1
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)
IV induction with diazepam and ketamine is rapid and allows early intubation.2
Only ketamine provides analgesia: good somatic analgesia but poor visceral analgesia. On its own it is not enough for major, very painful or visceral surgery.1,12
Acepromazine provides no analgesia, and diazepam's analgesia is negligible.5,11
Muscle relaxationRelaxed muscle tone — 50% (Partial)
A tranquilizer given before ketamine improves muscle relaxation.7
Blood pressure: May fall
Acepromazine causes hypotension. If you have given it to a dog, do not count on ketamine to raise blood pressure: ketamine cannot offset this fall, and the risk of hypotension remains.6,13,14
In cats, ketamine raises blood pressure and acepromazine lowers it; blood pressure may fall.1,13
Acepromazine ↓ Lowers: Dilates blood vessels and lowers blood pressure, especially at high doses or in hypovolemia.5,6,13
Diazepam – Little effect: Has little effect on the heart and circulation.11
Before you start: contraindications
Contraindication Do not give ketamine in: severe heart failure, suspected lung disease, hypertension, cerebrovascular injury, liver or kidney disease, eclampsia, glaucoma, seizures or epilepsy, myelography, or hypersensitivity to the drug. Surgery of the pharynx, larynx, trachea or bronchi without adequate muscle relaxation and intubation is also contraindicated.1
Contraindication Do not give acepromazine to an animal with hypotension, dehydration or hypovolemia; correct the dehydration first.5,6,8
Contraindication Do not give acepromazine to a pregnant animal.6
Cautions and notes
Caution Draw up each drug in its own syringe. Diazepam and ketamine are not compatible; do not draw them up in one syringe.1,3,6,9
Caution Do not give diazepam IM: IM injection is painful, absorption is unpredictable, and it may cause an abscess.5,10,11
Caution Not enough for a painful procedure: acepromazine provides no analgesia, diazepam's analgesia is negligible, and ketamine's analgesia is short and poor in the viscera. For surgery or a painful procedure, also choose an opioid.1,5,7,11,12
Caution For a longer procedure, maintain anesthesia with an inhalant; diazepam prolongs recovery.1
Caution Do not give diazepam alone to a healthy animal; it may cause excitement, especially in cats. Give ketamine immediately afterwards.1,8,11
Caution Monitor body temperature and keep the animal warm.5,6
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.2
Caution Boxers and brachycephalic breeds may faint (syncope); give a low dose.6
Caution Large breeds are more sensitive to acepromazine; give the lowest possible dose.6
Note Diazepam is reversed by flumazenil; acepromazine has no reversal agent.7,10,11
Caution In cats, part of the ketamine is excreted unchanged by the kidneys; use caution in kidney failure.2
Reversal and emergency drugs
FlumazenilReverses diazepam
Ampoule 0.5 mg in 5 mL (0.1 mg/mL)
First dose, starting from the lowest amount — Intravenous (IV): 0.01 mg/kg7
If sedation is excessive or prolonged, or breathing is weak. If needed, repeat the same amount until effect; up to 0.2 mg/kg in total.7,8
AtropineBradycardia
Ampoule 0.5 mg in 1 mL; do not confuse it with the 10 mg/mL ampoule