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Emergency And Acute Medicine – Amphetamine Poisoning
Core Overview
Amphetamine toxicity results from increased release of norepinephrine, dopamine, and serotonin, reduced catecholamine reuptake, and direct stimulation of α- and β-adrenergic receptors. These effects lead to a classic sympathomimetic toxidrome that can range from mild agitation to life-threatening hyperthermia, cardiovascular collapse, and multiorgan failure.
Underlying Causes
Amphetamine poisoning may occur from prescription stimulants such as amphetamine, dextroamphetamine, methamphetamine, methylphenidate, phentermine, and related agents. Illicit or “designer” drugs include methamphetamine (“crystal,” “ice,” “crank”), MDMA (“ecstasy”), MDA, methcathinone, and mephedrone, sometimes sold as “bath salts.” These substances are often synthesized in clandestine laboratories and may be smoked, injected, or insufflated, leading to rapid onset and prolonged toxicity.
Clinical Features
Central nervous system findings include agitation, delirium, hyperactivity, tremors, mydriasis, headache, hyperreflexia, seizures, status epilepticus, and coma. Psychiatric manifestations include euphoria, anxiety, aggression, hallucinations, and compulsive behaviors. Cardiovascular effects include tachycardia, hypertensive crisis, dysrhythmias, and potential cardiovascular collapse. Systemic complications include hyperthermia, diaphoresis, rhabdomyolysis, myoglobinuria, acute renal failure, disseminated intravascular coagulation, and anorexia.
History And Physical Examination
History should establish the substance used, dose, timing, route of exposure, and possible coingestions. Symptoms suggesting end-organ injury such as chest pain, dyspnea, headache, confusion, or vomiting should be sought. Physical examination commonly reveals agitation, tachycardia, diaphoresis, and mydriasis. Severe intoxication may present with hyperthermia, hypertensive crisis, seizures, hypotension, or respiratory distress. Careful evaluation for trauma, infection, focal neurologic deficits, cardiac murmurs, pneumothorax, and soft-tissue infections is essential.
Essential Emergency Evaluation
Vital signs must be closely monitored, with core temperature measurement required if hyperthermia is suspected. A temperature greater than 40°C is an ominous sign and mandates immediate intervention. Continuous cardiac monitoring and ECG assessment are essential to detect ischemia or dysrhythmias.
Diagnostic Testing
Laboratory evaluation includes electrolytes, glucose, BUN, creatinine, creatine phosphokinase, urinalysis for blood and myoglobin, and coagulation studies if DIC is suspected. Hyperkalemia and acidosis may accompany rhabdomyolysis and renal failure. Urine toxicology screening may identify coingestants, although some synthetic stimulants may not be detected. Aspirin and acetaminophen levels should be obtained if intentional overdose is possible. Imaging includes chest radiography for pulmonary edema or ARDS and head CT for altered mental status, focal deficits, or severe headache.
Conditions To Differentiate
Important alternative diagnoses include sepsis, thyroid storm, serotonin syndrome, neuroleptic malignant syndrome, pheochromocytoma, subarachnoid hemorrhage, cocaine toxicity, ethanol or sedative withdrawal, anticholinergic toxicity, and other causes of seizures or hypertensive emergencies.
Emergency Department Management
Prehospital care focuses on safety, IV access, and prevention of self-injury. Initial stabilization prioritizes airway, breathing, and circulation, IV fluid resuscitation, cardiac monitoring, and administration of naloxone, glucose, and thiamine if mental status is altered. Activated charcoal may be used early, and whole-bowel irrigation is indicated for body packers. Benzodiazepines are first-line therapy for agitation, seizures, and hypertension related to catecholamine excess. Severe hypertension may require α-blockade with phentolamine or vasodilators such as nitroprusside; β-blockers should be avoided. Hyperthermia requires aggressive sedation, active cooling, and paralysis with nondepolarizing agents if necessary. Rhabdomyolysis is treated with IV fluids to maintain adequate urine output, and dialysis is considered for renal failure or refractory hyperkalemia.
Disposition And Follow-Up
Admission is required for patients with hyperthermia, persistent altered mental status, hypertensive crisis, seizures, rhabdomyolysis, or ongoing tachycardia. Asymptomatic patients who remain stable after observation may be discharged. Referral for substance use treatment, detoxification, and rehabilitation should be arranged when appropriate.
Key Clinical Lessons And Common Errors
Severe amphetamine toxicity carries high morbidity and mortality if hyperthermia and agitation are not rapidly controlled. Core temperature monitoring is critical, and aggressive sedation with benzodiazepines plus active cooling is lifesaving. Rhabdomyolysis and hyperkalemia must be anticipated and treated early. Physical restraints should be minimized when possible, as they may worsen hyperthermia and acidosis. Benzodiazepines remain the cornerstone of treatment for symptomatic methamphetamine and amphetamine intoxication.
Core Overview
Amphetamine toxicity results from increased release of norepinephrine, dopamine, and serotonin, reduced catecholamine reuptake, and direct stimulation of α- and β-adrenergic receptors. These effects lead to a classic sympathomimetic toxidrome that can range from mild agitation to life-threatening hyperthermia, cardiovascular collapse, and multiorgan failure.
Underlying Causes
Amphetamine poisoning may occur from prescription stimulants such as amphetamine, dextroamphetamine, methamphetamine, methylphenidate, phentermine, and related agents. Illicit or “designer” drugs include methamphetamine (“crystal,” “ice,” “crank”), MDMA (“ecstasy”), MDA, methcathinone, and mephedrone, sometimes sold as “bath salts.” These substances are often synthesized in clandestine laboratories and may be smoked, injected, or insufflated, leading to rapid onset and prolonged toxicity.
Clinical Features
Central nervous system findings include agitation, delirium, hyperactivity, tremors, mydriasis, headache, hyperreflexia, seizures, status epilepticus, and coma. Psychiatric manifestations include euphoria, anxiety, aggression, hallucinations, and compulsive behaviors. Cardiovascular effects include tachycardia, hypertensive crisis, dysrhythmias, and potential cardiovascular collapse. Systemic complications include hyperthermia, diaphoresis, rhabdomyolysis, myoglobinuria, acute renal failure, disseminated intravascular coagulation, and anorexia.
History And Physical Examination
History should establish the substance used, dose, timing, route of exposure, and possible coingestions. Symptoms suggesting end-organ injury such as chest pain, dyspnea, headache, confusion, or vomiting should be sought. Physical examination commonly reveals agitation, tachycardia, diaphoresis, and mydriasis. Severe intoxication may present with hyperthermia, hypertensive crisis, seizures, hypotension, or respiratory distress. Careful evaluation for trauma, infection, focal neurologic deficits, cardiac murmurs, pneumothorax, and soft-tissue infections is essential.
Essential Emergency Evaluation
Vital signs must be closely monitored, with core temperature measurement required if hyperthermia is suspected. A temperature greater than 40°C is an ominous sign and mandates immediate intervention. Continuous cardiac monitoring and ECG assessment are essential to detect ischemia or dysrhythmias.
Diagnostic Testing
Laboratory evaluation includes electrolytes, glucose, BUN, creatinine, creatine phosphokinase, urinalysis for blood and myoglobin, and coagulation studies if DIC is suspected. Hyperkalemia and acidosis may accompany rhabdomyolysis and renal failure. Urine toxicology screening may identify coingestants, although some synthetic stimulants may not be detected. Aspirin and acetaminophen levels should be obtained if intentional overdose is possible. Imaging includes chest radiography for pulmonary edema or ARDS and head CT for altered mental status, focal deficits, or severe headache.
Conditions To Differentiate
Important alternative diagnoses include sepsis, thyroid storm, serotonin syndrome, neuroleptic malignant syndrome, pheochromocytoma, subarachnoid hemorrhage, cocaine toxicity, ethanol or sedative withdrawal, anticholinergic toxicity, and other causes of seizures or hypertensive emergencies.
Emergency Department Management
Prehospital care focuses on safety, IV access, and prevention of self-injury. Initial stabilization prioritizes airway, breathing, and circulation, IV fluid resuscitation, cardiac monitoring, and administration of naloxone, glucose, and thiamine if mental status is altered. Activated charcoal may be used early, and whole-bowel irrigation is indicated for body packers. Benzodiazepines are first-line therapy for agitation, seizures, and hypertension related to catecholamine excess. Severe hypertension may require α-blockade with phentolamine or vasodilators such as nitroprusside; β-blockers should be avoided. Hyperthermia requires aggressive sedation, active cooling, and paralysis with nondepolarizing agents if necessary. Rhabdomyolysis is treated with IV fluids to maintain adequate urine output, and dialysis is considered for renal failure or refractory hyperkalemia.
Disposition And Follow-Up
Admission is required for patients with hyperthermia, persistent altered mental status, hypertensive crisis, seizures, rhabdomyolysis, or ongoing tachycardia. Asymptomatic patients who remain stable after observation may be discharged. Referral for substance use treatment, detoxification, and rehabilitation should be arranged when appropriate.
Key Clinical Lessons And Common Errors
Severe amphetamine toxicity carries high morbidity and mortality if hyperthermia and agitation are not rapidly controlled. Core temperature monitoring is critical, and aggressive sedation with benzodiazepines plus active cooling is lifesaving. Rhabdomyolysis and hyperkalemia must be anticipated and treated early. Physical restraints should be minimized when possible, as they may worsen hyperthermia and acidosis. Benzodiazepines remain the cornerstone of treatment for symptomatic methamphetamine and amphetamine intoxication.
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