Ketamine
Ketamine Hydrochloride
Also known as: Ketaset · Ketaflo · Ketalar · Ketaject · VetaKet · Anaestamine · Anesketin · Ketavet · Narketan-10 · Vetalar-V · CI-581 · CL-369 · CN-52372-2 · ketamini hydrochloridum · Ketamine hydrochloride
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Audited v13 dosing evidence
Structured calculator evidenceKetamine/benzodiazepine combinations — Postoperative analgesia
Verified clinician required
NA
Governing clinical context (4)
- 1. Ketamine is used in many different combinations with other agents. The following are representative, but not necessarily inclusive; it is suggested to refer to a recent veterinary anesthesia reference for more information. 31,32
- 2. Do not confuse IV CRI dosages listed as mg/kg/HOUR with those listed as µg/kg/MINUTE.
- a) Ketamine/benzodiazepine combinations:
- Ketamine injection should be stored between 15°C to 30°C (59°F-86°F) and protected from light. The discard dates after first vial puncture vary by manufacturer; refer to the specific product label for further information.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Ketamine is a rapid-acting, dissociative general anesthetic and analgesic widely used in veterinary medicine.
- Drug Class: It is a phencyclidine (PCP) derivative.
- Clinical Effects: Induces a cataleptic state characterized by profound somatic analgesia, amnesia, and dissociation between the thalamocortical and limbic systems. Unlike traditional anesthetics, it does not induce stage III anesthesia.
- Reflex Preservation: Patients typically maintain cranial nerve reflexes, including pharyngeal, laryngeal, corneal, and pedal reflexes. Eyes often remain open.
- Cardiovascular: Generally stimulates the cardiovascular system (increasing heart rate, blood pressure, and cardiac output) due to increased sympathetic tone, making it useful in hemodynamically compromised patients (though contraindicated in hypertrophic cardiomyopathy).
Clinical Pearl: Because ketamine alone causes muscle rigidity and lacks visceral analgesia, it is almost always co-administered with muscle relaxants (e.g., benzodiazepines like midazolam or diazepam) or alpha-2 agonists (e.g., dexmedetomidine, xylazine) to ensure smooth induction, adequate muscle relaxation, and a smoother recovery.
Mechanism of action
Ketamine exerts its effects through multiple central nervous system pathways:
- NMDA Receptor Antagonism: Acts as a non-competitive antagonist at the N-methyl-D-aspartate (NMDA) receptor → binds to the PCP site inside the calcium channel pore → prevents glutamate-mediated calcium influx → blocks central sensitization and prevents the "wind-up" phenomenon associated with chronic or severe pain.
- Neurotransmitter Modulation: Inhibits GABA and blocks the reuptake of serotonin, norepinephrine, and dopamine in the CNS.
- CNS Dissociation: Depresses the thalamoneocortical system (responsible for sensory perception) while simultaneously activating the limbic system (involved in memory and emotion).
- Sympathetic Stimulation: Increases sympathetic tone by promoting norepinephrine release → leads to increased heart rate, cardiac output, and blood pressure. Note: Ketamine has direct negative inotropic effects on the myocardium, which are usually masked by this sympathetic surge unless the patient is catecholamine-depleted.
Safety & warnings
Contraindications
- Prior hypersensitivity reactions to ketamine
- Animals intended for human consumption
- Use as a sole agent for major surgery (due to poor muscle relaxation and visceral analgesia)
- Increased cerebrospinal fluid (CSF) pressure or head trauma
- Significant hypertension, heart failure, or arterial aneurysms
- Hypertrophic cardiomyopathy (HCM) in cats
- Increased intra-ocular pressure or open globe injuries (relative)
- Procedures involving the pharynx, larynx, or trachea (relative)
- Preexisting seizure disorders (use with extreme caution)
- Animals whose eyes are at risk of perforation
- Raised intraocular pressure (IOP)
- Raised intracranial pressure (ICP)
Adverse effects
- Hypertension
- Hypersalivation
- Respiratory depression (at high doses or rapid IV administration)
- Hyperthermia (especially in cats)
- Emesis
- Vocalization
- Erratic and prolonged recovery (emergence delirium)
- Dyspnea
- Spastic jerking movements and muscular tremors
- Seizures (up to 20% of cats at therapeutic doses)
- Hypertonicity and opisthotonos
- Cardiac arrest
- Pain after IM injection
- Eyes remain open (risk of corneal drying/ulceration)
- Cardiovascular depression and arrhythmias (in animals with high sympathetic tone, shock, or severe CV disease)
- Tachycardia (following high IV doses)
- Marked respiratory depression (in some animals)
- Skeletal muscle hypertonicity and spontaneous movement (if used alone)
- Spacey, abnormal behaviour or dysphoria during recovery (1-2 hours)
- Drug accumulation and prolonged recovery (with prolonged infusion)
Precautions
Cardiovascular Caution: Ketamine increases heart rate, blood pressure, and myocardial oxygen consumption. Avoid in patients where this is detrimental (e.g., unstable shock, congestive heart failure, hypertrophic cardiomyopathy).
Ocular Care: Cats' eyes remain open after receiving ketamine. Protect from injury and apply an ophthalmic lubricant (e.g., Lacri-Lube) to prevent excessive corneal drying.
- Hepatic/Renal Insufficiency: Use with caution. In cats, ketamine is excreted almost exclusively via the kidneys; reduce doses or use cautiously in feline renal disease.
- Sympathetic Tone: Use with caution in animals with preexisting increased sympathetic tone (e.g., pheochromocytoma, hyperthyroidism).
- Recovery: Minimize exposure to handling or loud noises during the recovery period to reduce the incidence of emergence reactions (delirium, thrashing), but continue to monitor vital signs closely.
- Hemorrhage: Because ketamine can increase blood pressure, careful control of post-surgical hemorrhage (e.g., declawing) is required.
Drug interactions
May prolong the anesthetic actions of ketamine
May prolong the recovery time after ketamine anesthesia
Recovery rates may be prolonged and the cardiac stimulatory effects of ketamine may be inhibited; close monitoring of cardiac status is recommended
Recommended not to use ivermectin in reptiles within 10 days of ketamine
May cause enhanced or prolonged respiratory depression
May induce severe hypertension and tachycardia; beta-blockers may be of benefit in treating these effects
Synergistic anaesthesia and prevention of muscle hypertonicity. Reversal of the alpha-2 agonist must be delayed until 45 minutes after ketamine administration to prevent unopposed ketamine excitation.
Synergistic anaesthesia and prevention of ketamine-induced skeletal muscle hypertonicity.
Monitoring
- Level of anesthesia and analgesia
- Respiratory function
- Cardiovascular status (heart rate, rhythm, blood pressure)
- Eyes (monitor to prevent drying or injury)
- Body temperature (monitor for hyperthermia or hypothermia)
- Heart rate and rhythm
- Respiratory rate and depth
- Depth of anaesthesia
- Corneal lubrication status
- Quality of recovery (monitor for dysphoria)
Pharmacokinetics
Half-life
Absorption
After IM injection in the cat, peak levels occur in approximately 10 minutes. Sublingual spray in cats is absorbed enough to have pharmacologic action.
Distribution
Distributed into all body tissues rapidly, with highest levels found in the brain, liver, lung, and fat. Plasma protein binding is approximately 50% in the horse, 53% in dogs, and 37-53% in cats.
Metabolism
In most species, metabolized in the liver principally by demethylation and hydroxylation. One active metabolite, nor-ketamine, has 10-30% of the activity of the parent compound. In cats, ketamine is almost exclusively excreted unchanged.
Elimination
Eliminated primarily in the urine. Redistribution out of the CNS is more of a factor in determining duration of anesthesia than is the elimination half-life.
Overdose
Ketamine has a wide therapeutic index (approximately 5 times greater than pentobarbital).
- Signs of Toxicity: When given too rapidly or in excessive doses, significant respiratory depression may occur.
- Treatment: Treatment using mechanically assisted respiratory support is recommended over the use of analeptic agents. In cats, yohimbine combined with 4-aminopyridine has been suggested for use as a partial antagonist.
Available products
Formulations
- Injection: 10 mg/mL
- Injection: 50 mg/mL
- Injection: 100 mg/mL
- Injectable: 100 mg/ml solution
Veterinary
- Ketamine HCl for Injection: 100 mg/mL in 10 mL vials (Ketaject, Ketaset, Keta-sthetic, Vetalar, VetaKet)
- Anaestamine 100 mg/ml injection
- Anesketin 100 mg/ml injection
- Ketaset 100 mg/ml injection
- Ketavet 100 mg/ml injection
- Narketan-10 100 mg/ml injection
- Vetalar-V 100 mg/ml injection
Human-labeled
- Ketamine HCl Injection: 10 mg/mL in 20 mL vials
- Ketamine HCl Injection: 50 mg/mL in 10 mL vials
- Ketamine HCl Injection: 100 mg/mL in 5 mL vials (Ketalar)
Regulatory status
POM-V CD SCHEDULE 2
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store between 15-30°C (59-86°F) and protect from light. Solution may darken upon prolonged exposure to light, which does not affect potency. Do not use if precipitates appear. Do not mix with barbiturates or diazepam in the same syringe or IV bag as precipitation may occur.
Client information
Important: Ketamine is a controlled substance and is only administered by veterinary professionals in a clinical setting.
- Eye Care: Your pet's eyes may remain open while under the effects of this medication. The veterinary team will apply a protective eye ointment to prevent drying and injury.
- Recovery Phase: Keep your pet in a quiet, dimly lit environment as they recover. Minimize loud noises, sudden movements, and excessive handling to prevent startle reactions, erratic movements, or hallucinations as the drug wears off.
- What to Watch For: Monitor for any unusual twitching, prolonged grogginess, or abnormal behavior, and report it to your veterinarian.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.