Substance Use Disorders (Clinical)

Alcohol withdrawal and Wernicke

A predictable timeline. Alcohol withdrawal unfolds on a schedule after the last drink, and the timing identifies both the syndrome and its danger.

Alcoholic hallucinosis keeps a clear sensorium; delirium tremens is defined by disorientation and clouded consciousness.

Benzodiazepines are the treatment, titrated to the CIWA-Ar score. Long-acting chlordiazepoxide and diazepam provide a smooth self-taper. In liver disease or the elderly, use the LOT drugs (lorazepam, oxazepam, temazepam), which are glucuronidated and skip oxidative phase I hepatic metabolism. Withdrawal seizures respond to benzodiazepines, not phenytoin. Severe or benzodiazepine-refractory delirium tremens requires ICU care, with phenobarbital as an adjunct.

Thiamine before glucose. In any patient with alcohol use disorder or malnutrition, give thiamine before or with dextrose: glucose metabolism consumes the remaining thiamine and can precipitate Wernicke encephalopathy, whose triad is encephalopathy (confusion), ophthalmoplegia, and ataxia. Treat Wernicke with IV thiamine. Untreated, it progresses to Korsakoff syndrome: irreversible anterograde amnesia with confabulation from mammillary body damage.

Alcohol use disorder: screening and relapse prevention

Screening. CAGE asks about the need to Cut down, being Annoyed by criticism, feeling Guilty, and needing an Eye-opener; ≥2 positive answers is a positive screen. The AUDIT questionnaire is the more detailed validated alternative. A positive screen leads to a brief intervention and assessment for use disorder.

Opioids: overdose, withdrawal, and MOUD

Overdose. The triad is miosis (pinpoint pupils), respiratory depression, and depressed consciousness. Support ventilation and give naloxone (IM, IV, or intranasal). Naloxone's short half-life means overdose with long-acting opioids such as methadone may need repeat dosing or an infusion, with observation for re-sedation; potent synthetic opioids such as fentanyl may also need repeated doses. Send patients home with naloxone.

Withdrawal is miserable but rarely dangerous, unlike alcohol or benzodiazepine withdrawal: mydriasis, lacrimation, rhinorrhea, yawning, piloerection ("cold turkey"), myalgias, nausea, diarrhea, and dysphoria, with a clear sensorium. Severity is scored with COWS. Clonidine, loperamide, and ondansetron relieve symptoms; buprenorphine or methadone treat it definitively.

In pregnancy, opioid use disorder is treated with methadone or buprenorphine maintenance rather than supervised withdrawal, and the newborn is monitored for neonatal opioid withdrawal.

Stimulants and sedative-hypnotics

Stimulants (cocaine, amphetamines) cause a sympathetic surge with risk of MI and stroke. Benzodiazepines come first for agitation and for cocaine chest pain, with aspirin and nitroglycerin for ischemia; avoid nonselective beta-blockers because of feared unopposed α-mediated vasoconstriction. Stimulant withdrawal (a "crash" of hypersomnia, hyperphagia, and depression) is unpleasant but not physiologically dangerous, apart from suicide risk.

Benzodiazepine overdose causes CNS and respiratory depression but is rarely fatal alone; it becomes dangerous combined with alcohol or opioids. Flumazenil reverses it but can precipitate withdrawal seizures in dependent users, so care is mainly supportive.

Benzodiazepine and barbiturate withdrawal, like alcohol withdrawal, can kill: tremor, autonomic hyperactivity, and seizures. Never stop abruptly; use a slow taper or convert to a long-acting benzodiazepine.

Motivational interviewing and nicotine

Motivational interviewing is a collaborative, patient-centered style for ambivalent patients: express Empathy, develop Discrepancy between goals and behavior, roll with Resistance rather than confronting it, and support Self-efficacy. Match the approach to the patient's stage of change.

Nicotine use disorder is treated with varenicline (a nicotinic partial agonist and the most effective single agent), bupropion, or nicotine replacement, often in combination (for example, a patch plus a short-acting gum or lozenge).