Sympathomimetic Toxicity Clinical Presentation

Updated: Apr 28, 2015
  • Author: Paul Kolecki, MD, FACEP; Chief Editor: Asim Tarabar, MD  more...
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Knowing that a sympathomimetic agent was ingested is helpful for treating a poisoned patient. Query patients about the use of cocaine, methamphetamine, and ecstasy. In addition, patients should be asked about their use of over-the-counter cold medications (containing ephedrine) and herbal preparations (eg, ephedra, Ma-Huang). Phenylpropanolamine used to be a very popular amphetamine sold over-the-counter; however, it was taken off the market by the Food and Drug Administration (FDA) because of the risk of intracranial hemorrhage associated with its use. The FDA banned the sale of ephedra and ephedra-containing products.

Maintain a high index of suspicion of sympathomimetic poisoning when treating an unknown overdose, especially in patients that present with the sympathomimetic toxidrome.

Another aid in the history of sympathomimetic poisoning is that the onset of symptoms usually occurs within 2 hours postexposure.

Life-threatening complications typically occur within 2-6 hours postexposure.



Adult sympathomimetic toxicity produces typical adrenergic signs and symptoms, some of which can be deadly.

  • Bronchospasm and wheezing can occur in patients who smoke crack cocaine. In addition, crack cocaine use can cause asthma exacerbations, pneumothorax, and lung injury.
  • Hyperthermia associated with sympathomimetic toxicity may result secondary to the destructive behavior and extreme agitation experienced by these patients. The abuse of sympathomimetic agents in hot, humid environments (eg, dance clubs, summer evenings) can further exacerbate hyperthermia. Seizures resulting from overdose can also produce hyperthermia. Sympathomimetic-induced hyperthermia can produce significant morbidity (from end-organ damage) and death.
  • Extreme hypertension can result in headache, hypertensive encephalopathy, and intracranial hemorrhage.
  • Sympathomimetic toxicity also can result in asymptomatic hypertension, which may require an urgent reduction in blood pressure.
  • The following cardiac arrhythmias may result from sympathomimetic toxicity:
    • Sinus and supraventricular tachycardia (including atrial fibrillation and atrial flutter)
    • Premature ventricular beats
    • Accelerated idioventricular rhythms, ventricular tachycardia, ventricular fibrillation, and torsades de pointes.
    • Second-degree and third-degree heart block (as a reflex response to hypertension)
  • Sympathomimetic-induced chest pain, myocardial ischemia, myocardial infarction, and cardiomyopathy (eg, cocaine) also can occur. [5]
  • Seizures, strokes, and intracerebral bleeds are well-documented complications of sympathomimetic toxicity.
  • Dissecting thoracic aneurysms and mesenteric ischemia are rare but deadly consequences of sympathomimetic poisoning.
  • Sympathomimetic toxic adult patients may also experience some nonlethal signs and symptoms, as follows:
    • Mydriasis
    • Tachycardia
    • Diaphoresis
    • Acute psychosis
    • Paranoia
    • Delirium
    • Bruxism (amphetamines and bath salts)
  • Although adult poisoning is well documented, pediatric sympathomimetic toxicity is not. Pediatric patients with sympathomimetic toxicity present with the same signs and symptoms observed in adults.
    • One study noted that some pediatric patients with sympathomimetic toxicity initially presented with inconsolable crying, vomiting, and abdominal pain.
    • These signs and symptoms are also the presenting features of many serious pediatric diseases (eg, sepsis, intussusception, intracranial lesion), and several of these pediatric patients received expensive ancillary tests to rule out significant disease.


See the list below:

  • Poisoning from sympathomimetic agents occurs secondary to the use of prescription agents, nonprescription agents, and illegal agents.
  • Typically, prescription and over-the-counter sympathomimetic agents are inhaled or orally administered.
  • In general, the inhalational agents (eg, albuterol, crack cocaine) have a quicker onset of action than the oral agents and a shorter duration of action.
  • Sympathomimetic toxicity following ingestion typically peaks 1-4 hours postingestion and last 4-8 hours, but sustained-release preparations may alter this time course.
  • The onset of toxicity following intravenous use of a sympathomimetic agent occurs within minutes.
  • Presently, many illegal sympathomimetic agents are commonly abused.
    • On the streets, some of these illegal agents have interesting names that, for the most part, are based on the psychological effects produced by the specific drug.
    • In general, all sympathomimetic agents are rapidly absorbed when ingested.
    • The popular designer amphetamines (eg, ecstasy) and ephedrine are abused mainly by the oral route.
    • Abuse of sympathomimetic agents often occurs at contemporary disco or rave party scenes, where adolescents use them before and during hours of rigorous dancing in crowded rooms with a hot and humid atmosphere.
    • Many reports of adolescent morbidity (eg, dehydration, hyperthermia, cardiac dysrhythmias) and mortality are associated with the use of illegal sympathomimetic agents at discos and rave parties. Other recreational drugs used at rave parties include marijuana, ketamine, gamma-hydroxybutyrate (GHB), and gamma-butyrolactone (GBL).
    • Some of the illegal sympathomimetic agents are more commonly abused by the inhalational route (eg, crack cocaine, methamphetamine) or the IV route (eg, cocaine, methamphetamine, methcathinone) than by the oral route.
  • The duration of action of illegal sympathomimetic agents differ based on their chemical structure. Methamphetamine has the chemical structure of amphetamine with an additional methyl group. The half-life of methamphetamine, however, is much longer (2-24 h) than that of amphetamine, thus partially accounting for methamphetamine's present popularity.
  • The route of abuse also contributes to the duration of action of some of these illegal sympathomimetic agents. The duration of action of cocaine is more than 3 hours if ingested. However, the duration of action is much shorter after nasal snorting (1-2 h), inhalation (15-30 min), or IV injection (15-30 min).