What is the management of barbiturate poisoning?

Management of Barbiturate Poisoning

Optimal supportive care with airway protection is mandatory in all cases of barbiturate poisoning, with multiple-dose activated charcoal (MDAC) as first-line enhanced elimination therapy, and extracorporeal treatment (ECTR) reserved for severe cases with prolonged coma, shock, or respiratory failure. 1, 2

Initial Stabilization and Assessment

Immediate Interventions

• Secure the airway and provide respiratory support, including intubation and mechanical ventilation for patients exhibiting respiratory depression, as barbiturates suppress the medullary respiratory center 1, 2
• Hemodynamic stabilization with aggressive fluid resuscitation is critical for hypotension and shock, since cardiovascular depression occurs when medullary vasomotor centers are depressed 1, 2
• Administer oxygen, naloxone (if co-ingestion suspected), glucose, and thiamine in patients with altered mental status 3

Clinical Assessment Parameters

• Monitor for the barbiturate toxidrome: CNS depression (sedation, sluggishness, lack of coordination, slow speech, drowsiness progressing to coma), respiratory depression with shallow breathing, and cardiovascular depression with hypotension 1
• Obtain serum barbiturate concentration, particularly for phenobarbital (therapeutic range 10-25 mg/L; >50 mg/L may induce coma; >80 mg/L may be fatal), though serum levels confirm diagnosis but do not reliably predict duration or severity of toxicity 1, 2
• Perform urine drug screen and blood ethanol concentration to identify co-ingested drugs, as combinations with other CNS depressants (alcohol, opiates, benzodiazepines) create additive life-threatening effects 1, 2

Enhanced Elimination: Multiple-Dose Activated Charcoal

MDAC (15-20 g orally every 6 hours) is the first-line enhanced elimination therapy and should be used in all significant barbiturate poisoning cases, particularly for phenobarbital and primidone 1, 2, 4

Critical Precautions for MDAC

• Only administer MDAC after the airway is secured and hemodynamic stabilization has been addressed 1, 2
• Gastric emptying decreases in barbiturate toxicity, increasing risks of impaction, gut perforation, and aspiration 1
• MDAC decreases phenobarbital elimination half-life from approximately 80 hours to 40 hours, though clinical benefit data are limited 4

Interventions NOT Recommended

• Urinary alkalinization is no longer recommended as first-line treatment because it does not significantly increase renal clearance and MDAC is considered superior 1, 2
• Gastric lavage and induced emesis have not consistently reduced mortality and are rarely indicated 5, 3

Extracorporeal Treatment (ECTR): Indications for Severe Cases

ECTR is indicated for long-acting barbiturate poisoning when ANY of the following conditions are met:

Strong Indications (Level 1D)

• Prolonged coma is present or expected 1, 2
• Shock persists after fluid resuscitation 1, 2
• Despite MDAC treatment, toxicity persists 1, 2

Moderate Indications (Level 2D)

• Despite MDAC treatment, serum barbiturate concentration rises or remains elevated 1
• Respiratory depression necessitating mechanical ventilation is present 1, 2

ECTR Implementation

• Initiate ECTR as soon as technically possible, ideally within 24 hours of barbiturate exposure 1, 2
• Continue MDAC concurrently with ECTR for maximal barbiturate removal, as the combination provides greater removal than either alone 1, 2
• Continue ECTR until clinical improvement is apparent 2
• The primary goal is to reduce duration of coma and incidence of complications (pneumonia, cardiorespiratory compromise, kidney failure) 1

Rationale for ECTR

The EXTRIP Workgroup consensus supports ECTR because: (1) death after severe barbiturate poisoning is commonly reported despite full supportive care; (2) no highly effective antidote exists; (3) ECTR significantly enhances barbiturate removal compared to endogenous elimination; (4) complications are infrequent; and (5) cost may be balanced by reduced ICU duration 1

High-Risk Populations Requiring Closer Monitoring

• Patients with chronic obstructive pulmonary disease are more susceptible to respiratory depression even at therapeutic doses 1, 2
• Patients with congestive heart failure are more vulnerable to cardiovascular effects and hypotension 1, 2
• Long-term barbiturate users tolerate higher doses but not higher serum concentrations before lethal toxicity, and are at greater risk of withdrawal if concentrations are reduced rapidly with ECTR 1

Common Pitfalls to Avoid

• Do not rely solely on ingested dose or serum concentrations to guide ECTR decisions—clinical status is paramount, as estimates are often inaccurate and interpatient variability is significant 1
• Do not delay airway protection—death from barbiturate overdose is often due to aspiration pneumonia caused by respiratory depression 1
• Do not use MDAC without first securing the airway—aspiration risk is significantly elevated 1, 2
• Recognize that patients can have rapid decline in mental or hemodynamic status even when initially appearing to compensate 6