Generic Name

Ketalar

Brand Names

for ketamine) is an N‑methyl‑D‑alanine derivative widely used as a dissociative anesthetic, intra‑operative analgesic, and emerging agent for depression and other refractory conditions.

Mechanism

• Primary: Competitive antagonist of the N‑methyl‑D‑aspartate (NMDA) glutamate receptor, blocking excitatory neurotransmission.
• Secondary:
• Modulates opioid receptors (µ and κ), contributing to analgesia.
• Inhibits voltage‑gated sodium channels and enhances norepinephrine release.
• Modulates intracellular signaling pathways (e.g., AMPA receptor up‑regulation, BDNF release) underlying antidepressant effects.
• Result: Dissociative anesthesia with analgesia, reduced airway reflexes, and preserved cardiopulmonary drive.

Pharmacokinetics

Indications

• Anesthesia
• Induction for short procedures; rapid onset and recovery.
• Maintenance of anesthesia in combination with propofol or volatile agents.
• Analgesia & Procedural Sedation
• Low‑dose infusion for acute pain, burn care, minor surgeries.
• Intravenous regional anesthesia (ketamine‑lidocaine cocktail).
• Psychiatric
• Rapid‑onset antidepressant for treatment‑resistant depression (low dose, 0.5 mg/kg IV).
• Adjunct for PTSD, anxiety disorders, and chronic pain.
• Emergency Medicine
• Analgesic IV for trauma; adjunct in severe sepsis or shock to mitigate catecholamine over‑stimulation.
• Rehabilitation & Rehabilitation
• Assisted ambulation in spinal cord injury; anti‑nausea prophylaxis.

Contraindications

• Contraindications
• Uncontrolled severe hypertension.
• Elevated intra‑ocular or intracranial pressure.
• Severe cardiovascular disease (especially heart failure, myocardial ischemia).
• Active psychosis or severe psychiatric disorders.
• Severe organ dysfunction (hepatic/renal impairment) unless dose adjusted.
• Warnings
• Psychotomimetic effects: hallucinations, delirium, agitation.
• Cardio‑pulmonary: tachycardia, arrhythmias; rarely, hypertension, myocardial ischemia.
• Abuse potential: Schedule III/Narcotic (vary by region). Monitor for dependence and misuse.
• Respiratory: Rare profound depression, mandating airway protection in higher doses.

Dosing

• Premedication: benzodiazepines (e.g., midazolam 1–2 mg) reduce psychotomimetic side‑effects.
• Adjuncts: opioids or anesthetic agents reduce ketamine dose requirements.

Adverse Effects

• Common
• Flushing, tachycardia, hypertension
• Nausea, vomiting
• Dysphoria, vivid dreams, hallucinations
• Respiratory depression (rare at therapeutic doses)
• Serious
• Seizures (hyper‑excitability)
• Psychosis, prolonged delirium
• Coronary vasospasm, myocardial ischemia
• Urinary tract toxicity (cystitis) with chronic use
• Ocular pressure elevation, especially in glaucoma

Monitoring

• Vital Signs: Continuous BP, HR, RR, SpO₂; watch for hypertension and tachycardia.
• Sedation Level: RASS or BIS for anesthetic depth.
• Airway: Airway patency, protective reflexes; consider intubation if deep sedation.
• Laboratory: Baseline liver and kidney function; monitor for emerging metabolic acidosis.
• Psychiatric Screening: Post‑infusion delirium screening (CAM‑ICU).

Clinical Pearls

• Cardiovascular Benefits: Ketamine’s sympathetic stimulation preserves cardiac output and protects diaphragm—ideal in patients with low cardiac reserve or impending respiratory failure.
• Dissociation Modulator: Co‑infusion of propofol or a low dose of etomidate reduces dissociative phenomena while maintaining analgesia.
• Antidepressant Rapidisation: A single infusion of 0.5 mg/kg IV can reduce suicidal ideation within hours—particularly useful in crisis stabilization units.
• Pediatric Use: Ketamine at 1–1.5 mg/kg IM is fast‑acting, minimal respiratory depression—excellent for battlefield or rural trauma.
• Avoid Caffeine: Caffeine antagonizes NMDA receptors; consider withholding stimulants prior to ketamine anesthesia to avoid tachycardia.
• Urological Caution: Chronic ketamine exposure can cause cystitis; include this counseling for patients on outpatient infusions.
• Drug Interactions:
• CYP2B6 inhibitors (e.g., efavirenz) increase ketamine plasma levels.
• CYP3A4 inducers (e.g., phenytoin) reduce ketamine levels; dose adjustment may be required.
• Respiratory Consideration: Although respiratory drive is preserved, high doses (>10 mg/kg) may depress ventilation; secure airway if sedation depth is uncertain.

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• *Ketalar content is updated to the best available evidence (June 2024). Clinicians should consult institutional protocols and drug formularies before use.*