special subjects
Opioid Toxicity and Withdrawal
Introduction
Opioids are euphoriants that cause sedation. Respiratory depression may occur with high doses and can be managed with antidotes (eg,naloxone) or endotracheal intubation and mechanical ventilation. Withdrawal manifests initially as anxiety and drug craving, followed by increased respiratory rate, diaphoresis, yawning, lacrimation, rhinorrhea, mydriasis, and stomach cramps and later by piloerection, tremors, muscle twitches, tachycardia, hypertension, fever, chills, anorexia, nausea, vomiting, and diarrhea. Diagnosis is clinical plus with urine tests. Withdrawal can be treated by substitution with a long-acting opioid (eg,methadone) orbuprenorphine(a mixed opioid agonist-antagonist). “Opioid” is a term for a number of natural substances (originally derived from the opium poppy) and their semisynthetic and synthetic analogues that bind to specific opioid receptors. Opioids, which are potent analgesics with a limited role in management of cough and diarrhea, are also common drugs of abuse because of their wide availability and euphoriant properties; see also Opioid Analgesics and 