Sedative-Hypnotic Agent Overdose

Key Features

• Sedative-hypnotics depress the CNS reticular activating system, cerebral cortex, and cerebellum

Clinical Findings

• Mild intoxication produces euphoria, slurred speech, ataxia, and even hypoglycemia

• Severe intoxication produces stupor, coma, bradycardia, hypotension, hypothermia, and respiratory arrest

• Death is usually due to pulmonary aspiration of gastric contents

• Massively intoxicated patients may appear dead, with no reflex responses or even electroencephalographic activity

Diagnosis

• Ethanol serum levels > 300 mg/dL (0.3 g/dL; 65 mmol/L) usually produce coma in a novice user, but regular users may remain awake at much higher levels

• Many agents not detected on urine toxicology screening

Treatment

• Activated charcoal

  • Administer 60–100 g orally or via gastric tube, mixed in aqueous slurry if given within 1 h of ingestion

  • Use when the patient has ingested a massive dose and the patient has been intubated to protect the airway

• Hemodialysis may be necessary for severe phenobarbital intoxication

• Flumazenil is a specific benzodiazepine antagonist and has no effect on ethanol, barbiturates, other sedative-hypnotic agents

  • Consider flumazenil, 0.2 mg over 30–60 seconds intravenously, repeated in 0.2–0.5 mg increments as needed up to a total dose of 3–5 mg

  • Caution: Flumazenil should rarely be used because it may induce seizures in patients with preexisting seizure disorder, benzodiazepine tolerance, or concomitant overdose with tricyclic antidepressants or other convulsant