section name header

Basics ⬇

[Section Outline]

Author:

Denise A.Whitfield

David A.Tanen

Description!!navigator!!

Etiology!!navigator!!

Overdose of barbiturates:

Diagnosis ⬆ ⬇

[Section Outline]

Signs and Symptoms!!navigator!!

History

  • Determine if there was an intentional overdose:
    • Pill bottles at the scene
    • History of depression or suicidal ideation
  • Determine if there was a medication error:
    • What other medications was the patient taking?
    • Were there any recent changes in dose?
  • Estimate how long the patient may have been unresponsive

Physical Exam

  • CNS abnormalities:
    • Ataxia to coma
  • Respiratory depression
  • Cardiovascular:
    • Bradycardia and hypotension
  • Ophthalmologic:
    • Miosis
    • Nystagmus
    • Dysconjugate gaze
  • Hypothermia
  • Bullae or “barb blisters”

Essential Workup!!navigator!!

ALERT
Barbiturate poisoning can mimic brain death:
  • Cannot pronounce a patient brain dead until barbiturate poisoning has been ruled out

Diagnostic Tests & Interpretation!!navigator!!

Lab

  • Electrolytes, BUN/creatinine, glucose:
    • Calculate anion gap
    • Assess for renal failure
  • Urinalysis:
  • Creatine phosphokinase for evidence of rhabdomyolysis
  • Urine toxicology screen
  • Obtain serum phenobarbital level (if suspected)
  • Acetaminophen and salicylate levels if suspected suicide attempt
  • Thyroid function tests

Imaging

Diagnostic Procedures/Surgery

  • Noncontrast head CT
  • Lumbar puncture

Differential Diagnosis!!navigator!!

Treatment ⬆ ⬇

[Section Outline]

Prehospital!!navigator!!

  • Moderate to severe poisonings require paramedic transport
  • Intubation is often necessary because of respiratory depression or loss of gag reflex
  • IV access and supplemental oxygen:
    • IV fluid bolus for hypotension

Initial Stabilization/Therapy!!navigator!!

  • ABCs:
    • Administer supplemental oxygen
    • Severe poisonings usually require endotracheal intubation
  • 0.9% NS:
    • Hypotensive patients require at least 1-2 L IV fluid resuscitation
    • Pressor support may be necessary for refractory hypotension
  • Activated charcoal effectively binds barbiturates and may decrease systemic absorption

ED Treatment/Procedures!!navigator!!

  • Administer 1 dose of activated charcoal:
    • Utility greatest if given within 1 hr of ingestion
    • Ensure patient is awake and alert (or airway protected) prior to administration
    • Consider “gut dialysis” with repeated dose activated charcoal (without sorbitol) given q2-4h (as long as bowel sounds are present)
  • Rewarm patient if hypothermic (see “Hypothermia”)
  • Treat hypotension resistant to IV fluid bolus with vasopressors (norepinephrine, epinephrine)
  • Treat hyperkalemia (from muscle breakdown) with calcium, sodium bicarbonate, insulin and glucose, and /or potassium-binding agents
  • Repeat phenobarbital level in 2-4 hr to determine whether level is increasing
  • Consider hemodialysis if patient has:
    • Decreased or no renal function
    • Prolonged coma
    • Serum phenobarbital level >100 mg/dL
    • Refractory hypotension
  • There is no role for urinary alkalinization

Medication!!navigator!!

First Line

  • Activated charcoal: 1 g/kg PO
  • Norepinephrine: 2-4 mcg/min IV titrating to desired effect (to max of 10 mcg/min)

Second Line

  • Epinephrine: 0.1 mcg/kg/min titrating to desired effect (to max of 1 mcg/kg/min)

Follow-Up ⬆ ⬇

[Section Outline]

Disposition!!navigator!!

Admission Criteria

ICU admission for:

  • Coma
  • Respiratory depression
  • Hypotension
  • Hypothermia
  • Rhabdomyolysis

Discharge Criteria

Asymptomatic after a minimum of 6 hr of observation with 2 consecutive subtoxic phenobarbital levels before discharge

Issues for Referral

  • If intentional overdose, will require psychiatric evaluation
  • For nonintentional overdose, referral for adjustment in medications

Follow-up Recommendations!!navigator!!

For nonintentional overdose, may need referral for adjustment in medications or change of medications to agents with a greater therapeutic window

Pearls and Pitfalls ⬆ ⬇

  • Hypothermia may be pronounced:
    • Ensure accurate core temperature is measured
  • Check for rhabdomyolysis, since the patient may have been down for a prolonged period of time
  • Barbiturate poisoning can cause prolonged coma:
    • Ensure medication effects have resolved prior to making diagnosis of brain death

Additional Reading ⬆ ⬇

  • GussawL, CarlsonA. Sedative hypnotics. In: Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed.Philadelphia, PA: Elsevier; 2018.
  • LeeDC. Sedative-hypnotics. In: HoffmanRS, NelsonLS, Howland MA, et al., eds. Goldfrank's Toxicologic Emergencies. 10th ed.New York: McGraw-Hill; 2015.
  • PondSM, OlsonKR, OsterlohJD, et al. Rand omized study of the treatment of phenobarbital overdose with repeated doses of activated charcoal . JAMA. 1984;251:3104-3108.
  • RobertsDM, BuckleyNA. Enhanced elimination in acute barbiturate poisoning—a systematic review . Clin Toxicol (Phila). 2011;49:2-12.

See Also (Topic, Algorithm, Electronic Media Element)

Codes ⬆

ICD9

967.0 Poisoning by barbiturates

ICD10

  • T42.3X1A Poisoning by barbiturates, accidental (unintentional), init

  • T42.3X2A Poisoning by barbiturates, intentional self-harm, init

  • T42.3X4A Poisoning by barbiturates, undetermined, initial encounter

SNOMED

  • 44003006 Poisoning by barbiturate (disorder)

  • 216497003 Accidental poisoning by barbiturates (event)

  • 418108003 Barbiturate poisoning of undetermined intent (disorder)

  • 296036006 Barbiturate overdose (disorder)