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For further information, see CMDT Part 38-48: Opiate & Opioid
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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
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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
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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
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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