Generic Name

Ketamine Hydrochloride

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Classification

FDA Approved Indications

• Induction and maintenance of anesthesia in procedures requiring sedation, profound analgesia, and amnesia
• Diagnostic and surgical procedures in hospitalized patients

Mechanism of Action

Ketamine primarily acts as an NMDA receptor antagonist, blocking glutamate receptors in the brain, which results in dissociative anesthesia, analgesia, and sedation.

Dosage and Administration

Adult: Typically 1-4.5 mg/kg IV for induction; maintenance doses vary based on procedure, often 0.1-0.5 mg/kg IV or 2-4 mg/kg IM

Pediatric: Dosing is similar to adults, with adjustments based on weight and age; dosing must be carefully controlled due to variability in response

Geriatric: Lower initial doses recommended due to increased sensitivity and potential for cardiovascular effects

Renal Impairment: Use with caution; no specific dose adjustment established but patient monitoring is advised

Hepatic Impairment: Adjust dosing as needed; metabolism may be prolonged

Pharmacokinetics

Absorption: Rapid IV absorption; IM absorption is also effective but slightly slower

Distribution: Widely distributed in body tissues, crosses the blood-brain barrier and placental barrier

Metabolism: Extensively metabolized in the liver via CYP450 enzymes to norketamine and other metabolites

Excretion: Metabolites are excreted primarily in urine

Half Life: Approximately 2-3 hours

Contraindications

• History of or suspected increased intracranial pressure, brain tumors or aneurysms
• History of psychosis or schizophrenia

Precautions

• Use with caution in patients with cardiovascular diseases, hypertension, or hepatic impairment; monitor for emergence reactions, including hallucinations and agitation

Adverse Reactions - Common

• Emergence reactions (hallucinations, nightmares, delirium) (Moderate)
• Increased blood pressure, tachycardia (Common)
• Nausea and vomiting (Common)

Adverse Reactions - Serious

• Airway adverse events, respiratory depression (rare with appropriate dosing) (Rare)
• Cardiovascular instability, myocardial ischemia in susceptible individuals (Rare)

Drug-Drug Interactions

• CNS depressants may enhance sedative effects
• Sympathomimetics may potentiate cardiovascular effects

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Patient/Family Teaching

• Inform about possible emergence reactions and the need for calm, quiet environment afterward
• Advise about the temporary effects on mental function and coordination
• Instruct not to operate heavy machinery or drive until fully recovered

Special Considerations

Black Box Warnings:

• Potential for respiratory depression and emergence reactions

Genetic Factors: No specific genetic predictors identified for response or adverse effects

Lab Test Interference: None documented

Overdose Management

Signs/Symptoms: Extreme sedation, respiratory depression, hypertension or hypotension, hallucinations, agitation

Treatment: Supportive care, airway management, benzodiazepines for agitation or hallucinations, vasodilators or vasopressors as needed for blood pressure issues

Storage and Handling

Storage: Store in a secure, upright container at controlled room temperature (20–25°C)

Stability: Stable under recommended storage conditions, discard unused portion after 24 hours in the vial