Liquid ketamine

Product Overview

Generic Name: Ketamine Hydrochloride

Chemical Name: (±)-2-(o-Chlorophenyl)-2-(methylamino)cyclohexanone hydrochloride [citation:2]

DEA Schedule: CIII (Schedule III Controlled Substance) [citation:3][citation:8]

Approved Use (Human): General anesthesia (diagnostic and surgical procedures)

Approved Use (Veterinary): Anesthetic use in cats, restraint in subhuman primates [citation:3][citation:8]

Ketamine was first synthesized in 1962 and approved by the FDA in 1970 as a safer alternative to phencyclidine (PCP). It produces a unique “dissociative anesthesia” state where the patient appears awake but is dissociated from their environment, with eyes open and nystagmus present.

Available Strengths (Injection)

Based on FDA, USP, and international regulatory data [citation:1][citation:2][citation:6]:

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Additional Veterinary Note: A combination solution containing ketamine (80 mg/ml) with xylazine (6 mg/ml) is also available for veterinary use [citation:9].

Physicochemical Properties

Strength (per ml)	Total Ketamine per Vial	Typical Vial Size	Primary Use Setting
10 mg/ml [citation:6]	200 mg	20 ml vial	Human (Hospital setting)
50 mg/ml [citation:2][citation:10]	500 mg (10 ml); 250 mg (5 ml)	10 ml; 5 ml	Human (Hospital / EMS)
100 mg/ml [citation:2][citation:3][citation:8]	500 mg (5 ml); 1000 mg (10 ml)	5 ml; 10 ml	Veterinary / Some human (off-label)

Parameter	Information
Appearance	Clear, colorless, sterile solution [citation:1]
pH	3.5 – 5.5 (slightly acidic) [citation:1][citation:2][citation:8]
Preservative	Benzethonium chloride (≤ 0.1 mg/ml) [citation:2][citation:3][citation:8]
Osmolality (50 mg/ml)	405 – 416 mOsmol/kg [citation:10]

Indications (Human Anesthesia)

Ketamine is indicated as the sole anesthetic agent for diagnostic and surgical procedures that do not require skeletal muscle relaxation [citation:2]. Specific procedures include:

• Burn debridement and dressing changes
• Orthopedic procedures (e.g., closed reductions, manipulations)
• Wound debridement and repair
• Skin grafting
• Dental procedures
• Cardiac catheterization in pediatric populations
• Radiological procedures (e.g., CT, MRI in uncooperative patients)

Induction Agent: Ketamine may also be used as an induction agent prior to administration of other general anesthetic agents.

Dosage and Administration

Important Administration Guidelines:

• Routes of administration: Intravenous (IV) or Intramuscular (IM) [citation:2][citation:8]
• Do not mix with barbiturates or diazepam in the same syringe (precipitate formation)
• Premedication with an anticholinergic (e.g., atropine) is recommended to reduce salivation
• Benzodiazepines (e.g., midazolam, diazepam) are often co-administered to reduce emergence reactions

Human Dosage References:

Route	Dose Range	Onset	Duration
IV (Intravenous)	1 – 4.5 mg/kg	30 – 60 seconds	5 – 15 minutes
IM (Intramuscular)	6.5 – 13 mg/kg	3 – 5 minutes	12 – 25 minutes

Subanesthetic Doses (Off-label, Clinical Use): Lower doses (0.5 – 2 mg/kg IV or IM) are sometimes used off-label for acute pain management, treatment-resistant depression, and procedural sedation, though these are not FDA-approved indications.

Mechanism of Action (Pharmacodynamics)

Ketamine produces a unique “dissociative anesthesia” state where the patient is awake but disconnected from their environment. Key pharmacologic actions include:

• NMDA Receptor Antagonism: Ketamine non-competitively blocks the N-methyl-D-aspartate (NMDA) receptor, which is involved in pain transmission, memory formation, and excitotoxicity [citation:9]
• σ-Receptor Activity: Interacts with sigma receptors, contributing to its psychotomimetic effects
• Analgesia: Potent analgesic effects at sub-dissociative doses; does not require intact spinal cord pathways
• Sympathetic Stimulation: Increases heart rate, blood pressure, and cardiac output (unlike most other anesthetics)

Unique Features of Dissociative Anesthesia:

• Eyes remain open with nystagmus
• Corneal and light reflexes are intact
• Pharyngeal and laryngeal reflexes are maintained (reduces aspiration risk)
• Skeletal muscle tone is increased, not decreased
• Patient may exhibit purposeful-looking movements (not responsive to commands)

Contraindications

Warnings and Precautions

Additional Important Warnings:

• Increased Salivation: Ketamine increases salivary and tracheobronchial secretions; premedication with an anticholinergic (atropine, glycopyrrolate) is recommended [citation:2]
• Laryngospasm: Although pharyngeal and laryngeal reflexes are maintained, laryngospasm can occur; airway management equipment should be immediately available
• Abuse Potential: Ketamine is a Schedule III controlled substance with a history of recreational abuse (“Special K”) leading to urologic toxicity (ketamine-induced cystitis) and cognitive impairment with chronic use
• Not for Use in Obstetrics: Use during labor and delivery is not recommended due to potential for neonatal depression

Common Side Effects

Predictable and Usually Transient:

• Emergence reactions (vivid dreams, hallucinations, confusion, agitation)
• Tachycardia and increased blood pressure
• Increased salivation and respiratory secretions
• Nausea and vomiting
• Nystagmus (involuntary eye movements)
• Increased intraocular pressure
• Increased skeletal muscle tone

Less Common/Serious Side Effects (Seek Medical Attention):

• Apnea or respiratory depression (rare at therapeutic doses, more common with rapid IV administration or co-administered CNS depressants)
• Severe hypertension or cardiac arrhythmias
• Laryngospasm
• Ketamine-induced cystitis (chronic use: painful bladder syndrome, hematuria, reduced bladder capacity)

Drug Interactions

Drug Class	Interaction Effect	Recommendation
Barbiturates (e.g., thiopental)	Chemical incompatibility; precipitate formation	Do not mix in same syringe or IV line without flushing
Diazepam / Benzodiazepines	Reduces emergence reactions; may prolong recovery; chemical incompatibility (precipitate)	Administer separately; dose reduction of ketamine may be required
Opioids	Additive CNS and respiratory depression	Monitor respiratory status closely
Sympathomimetics / Halogenated Anesthetics	Increased risk of hypertension and cardiac depression	Use with caution; monitor vital signs
Thyroid Hormones	May increase risk of hypertension and tachycardia	Contraindicated in thyrotoxicosis

Adverse Effects by System

Cardiovascular: Direct myocardial depression is offset by centrally mediated sympathetic stimulation, resulting in increased heart rate, blood pressure, and cardiac output. Effects are typically minimized by prior administration of benzodiazepines.

Respiratory: Respiratory depression is rare at therapeutic doses. Apnea occurs more frequently with rapid IV administration or concurrent use of other CNS depressants. Protective airway reflexes are typically maintained.

Ocular: Intraocular pressure increases. Not recommended in patients with glaucoma or penetrating eye injury.

Genitourinary (Chronic Use): Recreational abuse of ketamine is associated with ulcerative cystitis, characterized by frequency, urgency, dysuria, hematuria, and reduced bladder capacity.

Overdose

Signs of Overdose: Severe respiratory depression, apnea, prolonged anesthesia, cardiac arrhythmias, seizures.

Emergency Management:

• Supportive care: Maintain airway, provide assisted ventilation, administer oxygen
• IV fluids and vasopressors for hypotension if required
• Seizures: Benzodiazepines (IV lorazepam or diazepam) are first-line
• No specific antidote for ketamine overdose
• Call Poison Control (1-800-222-1222) or 911 immediately

Storage and Stability

Storage Requirements:

• Store at controlled room temperature (59°F – 86°F / 15°C – 30°C)
• Protect from light
• Do not freeze
• Multiple-dose vials contain a preservative; use within recommended period after opening (typically 28 days)
• If solution is discolored or contains particulate matter, do not use

Shelf-Life: Novel preservative-free preparations have demonstrated >6 months stability at room temperature [citation:5].

Pregnancy and Lactation

Pregnancy Category: Not formally established; generally avoided unless no safer alternative.

Lactation: Ketamine is excreted into breast milk. Caution in breastfeeding women; consider withholding breastfeeding for 6–12 hours following anesthesia.

Legal Status (United States)

Ketamine is classified as a Schedule III (CIII) controlled substance under the Controlled Substances Act [citation:3][citation:8]. Key restrictions include:

• Prescription required — no refills without a new prescription
• DEA registration required for prescribing and dispensing (CIII medications)
• Records must be maintained and available for inspection
• Illegal to possess without a valid prescription

Educational Summary

Ketamine Hydrochloride Injection is a rapid-acting, nonbarbiturate dissociative anesthetic producing a unique state of analgesia, amnesia, and catalepsy while maintaining protective airway reflexes [citation:2]. It is supplied as a clear, colorless, sterile solution with pH 3.5–5.5 in concentrations of 10 mg/ml, 50 mg/ml (human), and 100 mg/ml (primarily veterinary) [citation:1][citation:2][citation:3]. Ketamine acts as an NMDA receptor antagonist and is indicated for diagnostic and surgical procedures, including burn care, orthopedics, and wound debridement [citation:2][citation:9]. Key contraindications include severe hypertension, glaucoma, increased intracranial pressure, and psychosis. Common adverse effects include emergence reactions (vivid dreams, hallucinations), tachycardia, and increased secretions [citation:2]. Premedication with benzodiazepines reduces emergence reactions; anticholinergics reduce secretions [citation:2]. Ketamine is a Schedule III controlled substance with abuse potential; chronic recreational use is associated with ketamine-induced cystitis and cognitive impairment.

Note: This information is for pharmaceutical educational and pharmacy reference purposes only. Ketamine is a Schedule III controlled substance available by prescription only for use in hospital settings by qualified anesthesiologists. This content does not constitute medical advice. If you or someone you know is experiencing an overdose or severe adverse reaction, call emergency services immediately.