Opioid Poisoning

Widely varying potencies and durations of action (eg, some illicit fentanyl derivatives are 2000 times more potent than morphine)

In recent years, poisonings and fatalities have been reported due to the illicit use of fentanyl and the presence of fentanyl and its derivatives in counterfeit medications

Heroin's duration of action is usually 3–5 h; methadone, 48–72 h

Euphoria, drowsiness, and constricted pupils can occur with mild intoxication

Severe intoxication may cause

• Hypotension

• Bradycardia

• Hypothermia

• Coma

• Pulmonary edema

• Respiratory arrest

Death usually results from apnea or pulmonary aspiration

Methadone may cause QT interval prolongation and torsades de pointes

Tramadol, dextromethorphan, and meperidine also occasionally cause seizures

Meperidine metabolite normeperidine can cause seizures, particularly with repeated use in patients with chronic kidney disease

Skin-popping, especially with "black tar" heroin, associated with wound botulism and tetanus

Buprenorphine

• Newer partial agonist opioid used in some outpatient drug treatment programs

• May precipitate acute withdrawal symptoms when added to an opioid regimen

Routine urine toxicology screening usually positive for patients with heroin, morphine, codeine overdose

Toxicology screening may be falsely negative if opioid is methadone, fentanyl, oxycodone

Activated charcoal

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

• Do not give to comatose or convulsing patients unless airway protected by cuffed endotracheal tube

Naloxone

• Administer 4 mg intranasally if no intravenous access is available

• Otherwise, administer 0.2–2 mg intravenously; repeat as needed to awaken the patient and maintain airway protective reflexes and spontaneous breathing

• Effect duration: ~2–3 h

• Repeated doses may be necessary for intoxication by methadone or other long-acting drugs

• Large doses (10–20 mg) may be needed for codeine, fentanyl derivatives

• Continuous observation for at least 3 h after the last naloxone dose is mandatory