Clinical beta

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Drug Monograph

Ketamine

USE IF: Severe pain, procedural sedation, RSI in unstable patients

AVOID IF: Uncontrolled hypertension, active psychosis

Ketamine

NMDA receptor antagonist (dissociative anesthetic)

ED sedationAnalgesiaRSIICU adjunct

Indication

Severe pain, procedural sedation, RSI in unstable patients

At a glance

INDICATION -> Dissociative anesthetic providing analgesia + sedation with preserved airway reflexes

ADULT DOSE -> Analgesia 0.1-0.3 mg/kg IV; sedation 1-1.5 mg/kg IV; IM 4-5 mg/kg

MAX DOSE -> Procedural total about 2 mg/kg IV

CONTRA -> Rapid IV push, high-dose infusion outside ICU, uncontrolled HTN, active psychosis

ANTIDOTE -> None

Quick facts

Onset

IV 30-60 sec; IM 2-5 min

Duration

Peak 1-5 min; duration IV 10-20 min, IM 15-30 min; half-life 2-4 h.

Routes

IV, IM, PO, IN

Pregnancy

Avoid unless necessary

Renal

No adjustment

Hepatic

Reduce dose

Do not miss

Time to action: IV 30-60 sec, IM 2-5 min

Critical airway risk

  • Laryngospasm risk (rare but critical).

Critical risks

  • Sympathetic surge can cause HTN/tachycardia.
  • Emergence reactions (hallucinations, agitation).
  • Hepatotoxicity risk rises with prolonged infusion.
  • Preserves airway reflexes but DOES NOT guarantee airway protection -> aspiration remains possible.

Antidote

  • No specific antidote -> supportive care.

High-risk scenarios

  • Analgesic dose is not dissociative dose (common mismatch).

Key interactions

  • Theophylline.
  • CNS depressants.
  • Sympathomimetics.
  • SSRIs/SNRIs.
  • Levothyroxine.

Indications

Primary

  • Procedural sedation
  • Acute severe pain (opioid-sparing)
  • RSI induction

Secondary

  • ICU sedation adjunct
  • Status asthmaticus
  • Bronchodilation effect supports use in severe asthma

Other

  • Depression (specialist use)
  • Chronic pain syndromes

Dosing

Standard: Analgesia: 0.1-0.3 mg/kg IV

Max daily dose

  • Procedural sedation total typically around 2 mg/kg IV.

Adult - IV

  • Sedation: 1-1.5 mg/kg IV.
  • Induction: 1-2 mg/kg IV.
  • RSI induction: 1-2 mg/kg IV (preferred in hemodynamically unstable patients).
  • Infusion: 0.1-0.4 mg/kg/hr.

Additional routes / blocks

  • Low dose 0.1-0.3 mg/kg = analgesia.
  • Higher dose 1-2 mg/kg = dissociative anesthesia.
  • Analgesia: 0.1-0.3 mg/kg IV (slow push).
  • IM dissociation: 4-5 mg/kg.

Pediatric

  • IV: 1-1.5 mg/kg.
  • IM: 4 mg/kg.

Renal adjustment

  • No dose change usually required.

Hepatic adjustment

  • Reduce dose; avoid prolonged high exposure where possible.

Warnings

Clinical warnings

  • Laryngospasm risk ↑ with rapid IV push or airway stimulation.
  • Hypertension and tachycardia from sympathetic stimulation.
  • Increases HR and BP via sympathetic stimulation -> useful in shock, dangerous in CAD/aortic dissection.
  • Emergence reactions (hallucinations, agitation) -> reduce risk with benzodiazepine and calm environment.
  • Hypersalivation -> consider atropine or glycopyrrolate.
  • Hepatotoxicity with prolonged use.
  • Cystitis with chronic exposure.
  • Does NOT significantly increase ICP in ventilated patients -> safe in most RSI settings.
  • Causes bronchodilation -> preferred in severe asthma and status asthmaticus.

Adverse effects

  • Common: nausea, vomiting, nystagmus, dissociation.
  • Serious: laryngospasm, severe agitation, hypertensive crisis.

Contraindications / caution

Do not use

  • Severe uncontrolled hypertension.
  • Active psychosis.
  • Known hypersensitivity.

Use caution / avoid high doses

  • Cardiac disease.
  • Raised ICP.
  • Liver disease.
  • Elderly.

Drug interactions

  • Theophylline -> increased seizure risk.
  • CNS depressants -> increased respiratory depression/sedation.
  • Sympathomimetics -> additive HTN/tachycardia.
  • SSRIs/SNRIs -> potential BP elevation.
  • Levothyroxine -> increased cardiovascular effects.

Special populations

Pediatrics

Widely used with weight-based protocols and full monitoring.

Pregnancy

Avoid unless emergency indication.

Breastfeeding

Likely low risk after single dose.

Elderly

Reduce dose and titrate slowly.

Liver disease

Monitor LFTs and reduce dose.

Renal impairment

No routine adjustment required.

Administration

  • IV slow push over at least 1 minute.
  • Use infusion pump for continuous dosing.
  • Full monitoring required (SpO2, BP, HR).
  • Airway equipment must be immediately available.
  • Suction should be immediately available due to hypersalivation risk.
  • IM route is useful when IV access is not available.

Monitoring

  • BP, HR, RR, SpO2.
  • Respiratory depression may be delayed -> do not rely on early normal SpO2.
  • Mental status and emergence reactions.
  • LFTs if prolonged infusion/use.
  • Urinary symptoms in chronic/repeated exposure.
  • Sedation depth and recovery profile.

Overdose / toxicity

Airway + 100% oxygen -> control agitation (benzodiazepine) -> monitor BP/HR -> supportive care (no specific antidote).

Recognition

  • Toxic dose varies by context and co-ingestants.
  • Agitation, HTN, tachycardia; respiratory depression is less common but possible.

Immediate actions

  • Benzodiazepines for severe agitation.
  • Airway/ventilatory support as needed.
  • Supportive hemodynamic care.

Antidote

  • No specific antidote -> supportive care.

Decontamination

  • Not usually relevant for parenteral use.

Escalation

  • ICU if severe cardiorespiratory or neuropsychiatric toxicity.

Clinical pearls

Common mistakes, resistance logic, and bedside traps

RSI hemodynamics

  • Often best RSI induction option in hypotensive patients.

Dose distinction

  • Analgesic dose is not sedative/dissociative dose (frequent error).

Push speed

  • Slow IV push reduces laryngospasm risk and emergence reactions.

Airway myth

  • Preserves airway reflexes but DOES NOT guarantee airway protection -> aspiration still possible.

Emergence strategy

  • Adjunct benzodiazepine can reduce emergence reactions in selected patients (use cautiously).

Core identity

  • Ketamine is NOT a pure sedative - it is a dissociative anesthetic.
  • Analgesia is present (unlike propofol).
  • Unlike propofol -> maintains BP and provides analgesia.
  • Best agent in hypotension and asthma in many emergency settings.

Pharmacokinetics

  • Rapid CNS penetration.
  • Hepatic metabolism via CYP3A4 and CYP2B6.
  • Active metabolite: norketamine.
  • Renal excretion of metabolites.
  • Low oral bioavailability.

Mechanism of action

  • NMDA receptor antagonism.
  • Produces dissociative anesthesia with analgesia.
  • Also modulates glutamate and opioid-related pathways.

Common brand names

Saudi Arabia

Ketalar · Tekam

Global

Generic ketamine

Common trade names are curated examples only — formulations and availability vary. Verify the exact product name with your local pharmacy and national regulator before prescribing or dispensing.

Country practice notes

  • Widely used in GCC emergency departments for trauma and procedures.
  • Preferred RSI agent in hypotensive/septic patients.
  • Available as Ketalar and Tekam across Gulf hospital formularies.
  • Increasing ICU use as adjunct sedation rather than sole sedative.

Saudi Arabia — confirm with local formulary.