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Emergency And Acute Medicine – Hallucinogen Poisoning
Core Concept
Hallucinogen poisoning refers to toxic exposure to substances that predominantly alter perception, cognition, and mood. These agents act by potentiating neurotransmitter release or binding directly to central nervous system receptors. The serotonergic system (5-hydroxytryptamine, 5-HT) is most commonly involved, with many hallucinogens acting as agonists or antagonists at 5-HT receptor subtypes. Additional pathways affected include norepinephrine, N-methyl-D-aspartate (NMDA), and dopamine systems.
Cause And Exposure Patterns
Most hallucinogen exposures are intentional. Common agents include indoleamines such as lysergic acid diethylamide (LSD), with effects lasting 6–12 hours, and morning glory (Ipomoea species). Tryptamines include psilocybin from Psilocybe mushrooms, which are frequently adulterated with LSD, as well as N,N-dimethyltryptamine (DMT), 5-MeO-DMT (“foxy-methoxy”), and related compounds. Phenylethylamines (hallucinogenic amphetamines) include methylenedioxyamphetamine (MDA), methylenedioxymethamphetamine (MDMA, “ecstasy,” duration 8–12 hours), methylenedioxyethylamphetamine (MDEA), paramethoxyamphetamine, dimethoxyamphetamine, and mescaline from the peyote cactus, which is often adulterated with LSD and lasts 6–12 hours. Arylcycloalkylamines include phencyclidine (PCP), with highly variable duration reported from 11–96 hours, and ketamine, with effects lasting 30–120 minutes depending on route. Anticholinergic plant sources include deadly nightshade (Atropa belladonna) and jimsonweed (Datura stramonium). Other agents include piperazines such as benzylpiperazine (BZP) and trifluoromethylphenylpiperazine (TFMPP), dextromethorphan (DXM) with duration 3–6 hours, and marijuana.
Clinical Findings And Presentation
Clinical effects vary considerably by agent, dose, and individual susceptibility. Symptoms may last 4–12 hours and up to 96 hours in some cases. Hallucinogen intoxication is typically characterized by sympathetic arousal. Patients are often oriented and able to provide a history of exposure even while experiencing delusions. Early symptoms include nausea, flushing, chills, and tremor. Neurologic effects often begin with restlessness and dizziness, and a desire to laugh is common with Psilocybe mushroom ingestion. Psychiatric manifestations include anxiety, despair, helplessness, and dread. Perceptual disturbances include visual distortion or intensification, tactile distortions (especially with mescaline), and synesthesia such as “seeing sounds.” Religious or mystical experiences and sleep disruption may occur.
Neurologic signs include bizarre behavior, speech disruption, mydriasis, piloerection, and hyperreflexia. Massive exposures may result in coma. Convulsions are most often associated with hallucinogenic amphetamines, and children may develop hyperpyrexia after Psilocybe ingestion. Pulmonary findings include mild tachypnea, with respiratory arrest possible in severe intoxication. Cardiovascular effects include tachycardia, hypertension, dysrhythmias, and intracerebral hemorrhage, particularly with hallucinogenic amphetamines. Gastrointestinal symptoms include nausea and vomiting, especially with mescaline. Metabolic complications include hyperpyrexia, particularly with MDMA use in crowded environments such as rave clubs, which may progress to hepatic failure, renal failure, and disseminated intravascular coagulation and can be fatal. Hyponatremia has been reported with MDMA. High doses may disrupt platelet serotonin function, leading to coagulopathies and hemorrhage.
History And Physical Examination
History should focus on identifying the substance or substances used, route of exposure, quantity, time of ingestion, and setting of exposure. Physical examination requires accurate vital signs, with particular attention to body temperature, and a detailed neurologic and psychiatric assessment.
Key Emergency Workup
Initial evaluation should include continuous monitoring of vital signs and core temperature measurement. Cardiac monitoring is recommended. Assess for rhabdomyolysis by measuring creatine kinase and evaluating urine for myoglobin.
Laboratory And Imaging Evaluation
Laboratory testing may include electrolytes, blood urea nitrogen, creatinine, glucose, coagulation studies, and arterial or venous blood gas analysis as clinically indicated. Urine toxicology screening is rarely helpful because most hallucinogens are not detected on routine screens, amphetamine assays may be negative for hallucinogenic amphetamines such as MDMA, and distinguishing specific agents rarely changes management. Imaging should be guided by clinical suspicion and may include chest radiography for suspected aspiration, aortic pathology, or trauma, head CT for intracranial hemorrhage or lesions, and abdominal radiography if ingested drug packets are suspected.
Differential Considerations
The differential diagnosis includes hypoglycemia, meningitis, encephalitis, sepsis, intracranial hemorrhage or mass lesions, withdrawal syndromes (ethanol, sedative–hypnotics, baclofen), serotonin syndrome (particularly with co-ingestion of serotonergic agents), primary psychiatric illness including prolonged psychosis associated with LSD, chronic amphetamine or cocaine use, steroid-induced psychosis, and infectious or febrile seizures in hyperpyrexic children.
Prehospital Management
Management controversies include the choice between benzodiazepines, neuroleptics, or physical restraints for agitation. Benzodiazepines are generally preferred. Sedation may obscure symptoms and limit history but is often necessary for safe transport. Hyperthermic patients should be sedated rather than physically restrained, and cooling measures should be initiated early.
Initial Stabilization Approach
Management begins with airway, breathing, and circulation assessment. Aggressive cooling is required for hyperthermia. Establish IV access and provide isotonic fluids for dehydration or suspected rhabdomyolysis. In patients with altered mental status, check blood glucose and consider naloxone, dextrose, and thiamine as indicated.
Emergency Department Treatment
Supportive care is the mainstay. Cooling measures include cool mist and fans. Benzodiazepines are first-line therapy for agitation, anxiety, or autonomic instability. Paralysis with intubation may be required in severe cases, generally avoiding succinylcholine. Neuroleptics are rarely used because they may intensify hallucinogenic effects and lower the seizure threshold. Activated charcoal is generally not helpful due to rapid absorption and delayed presentation, but may be considered within 2–3 hours of ingestion in patients with a protected airway, especially for anticholinergic agents or ingested seeds. Patients should be placed in a quiet, calm environment. Maintain urine output at 2–3 mL/kg/hr and consider urine alkalinization when treating rhabdomyolysis.
Medication Options
Benzodiazepines such as diazepam 5–10 mg IV (pediatric dose 0.2–0.5 mg/kg) or lorazepam 1–4 mg IV/IM (pediatric dose 0.02–0.05 mg/kg) may be repeated as needed. Dextrose should be administered for hypoglycemia. Haloperidol 2.5–5 mg IV/IM may be used cautiously in adults for refractory agitation, but is generally avoided in children. Naloxone may be administered when opioid co-ingestion is suspected. Sodium bicarbonate infusion may be used for rhabdomyolysis to maintain urine alkalinity. Thiamine 100 mg IV or IM is recommended in at-risk patients.
Disposition And Follow-Up
Admission is indicated for severe intoxication, atypical or prolonged presentations, symptoms persisting longer than 12 hours, or prolonged agitation and hyperthermia with risk of rhabdomyolysis or organ damage. Most patients may be discharged after observation once asymptomatic and clinically stable. Suspected pediatric abuse or neglect requires referral to child protective services. Discharged patients should be advised to follow up with a primary care provider, psychiatrist, or substance use counseling service.
Clinical Pearls And Pitfalls
Hyperthermia must be recognized and treated immediately with aggressive temperature reduction. Violent or agitated patients require appropriate physical and chemical restraints to ensure safety. Serial examinations and vital sign monitoring, especially temperature, are essential. Do not assume clinical improvement once agitation subsides, as deterioration to severe toxicity may still occur.
Core Concept
Hallucinogen poisoning refers to toxic exposure to substances that predominantly alter perception, cognition, and mood. These agents act by potentiating neurotransmitter release or binding directly to central nervous system receptors. The serotonergic system (5-hydroxytryptamine, 5-HT) is most commonly involved, with many hallucinogens acting as agonists or antagonists at 5-HT receptor subtypes. Additional pathways affected include norepinephrine, N-methyl-D-aspartate (NMDA), and dopamine systems.
Cause And Exposure Patterns
Most hallucinogen exposures are intentional. Common agents include indoleamines such as lysergic acid diethylamide (LSD), with effects lasting 6–12 hours, and morning glory (Ipomoea species). Tryptamines include psilocybin from Psilocybe mushrooms, which are frequently adulterated with LSD, as well as N,N-dimethyltryptamine (DMT), 5-MeO-DMT (“foxy-methoxy”), and related compounds. Phenylethylamines (hallucinogenic amphetamines) include methylenedioxyamphetamine (MDA), methylenedioxymethamphetamine (MDMA, “ecstasy,” duration 8–12 hours), methylenedioxyethylamphetamine (MDEA), paramethoxyamphetamine, dimethoxyamphetamine, and mescaline from the peyote cactus, which is often adulterated with LSD and lasts 6–12 hours. Arylcycloalkylamines include phencyclidine (PCP), with highly variable duration reported from 11–96 hours, and ketamine, with effects lasting 30–120 minutes depending on route. Anticholinergic plant sources include deadly nightshade (Atropa belladonna) and jimsonweed (Datura stramonium). Other agents include piperazines such as benzylpiperazine (BZP) and trifluoromethylphenylpiperazine (TFMPP), dextromethorphan (DXM) with duration 3–6 hours, and marijuana.
Clinical Findings And Presentation
Clinical effects vary considerably by agent, dose, and individual susceptibility. Symptoms may last 4–12 hours and up to 96 hours in some cases. Hallucinogen intoxication is typically characterized by sympathetic arousal. Patients are often oriented and able to provide a history of exposure even while experiencing delusions. Early symptoms include nausea, flushing, chills, and tremor. Neurologic effects often begin with restlessness and dizziness, and a desire to laugh is common with Psilocybe mushroom ingestion. Psychiatric manifestations include anxiety, despair, helplessness, and dread. Perceptual disturbances include visual distortion or intensification, tactile distortions (especially with mescaline), and synesthesia such as “seeing sounds.” Religious or mystical experiences and sleep disruption may occur.
Neurologic signs include bizarre behavior, speech disruption, mydriasis, piloerection, and hyperreflexia. Massive exposures may result in coma. Convulsions are most often associated with hallucinogenic amphetamines, and children may develop hyperpyrexia after Psilocybe ingestion. Pulmonary findings include mild tachypnea, with respiratory arrest possible in severe intoxication. Cardiovascular effects include tachycardia, hypertension, dysrhythmias, and intracerebral hemorrhage, particularly with hallucinogenic amphetamines. Gastrointestinal symptoms include nausea and vomiting, especially with mescaline. Metabolic complications include hyperpyrexia, particularly with MDMA use in crowded environments such as rave clubs, which may progress to hepatic failure, renal failure, and disseminated intravascular coagulation and can be fatal. Hyponatremia has been reported with MDMA. High doses may disrupt platelet serotonin function, leading to coagulopathies and hemorrhage.
History And Physical Examination
History should focus on identifying the substance or substances used, route of exposure, quantity, time of ingestion, and setting of exposure. Physical examination requires accurate vital signs, with particular attention to body temperature, and a detailed neurologic and psychiatric assessment.
Key Emergency Workup
Initial evaluation should include continuous monitoring of vital signs and core temperature measurement. Cardiac monitoring is recommended. Assess for rhabdomyolysis by measuring creatine kinase and evaluating urine for myoglobin.
Laboratory And Imaging Evaluation
Laboratory testing may include electrolytes, blood urea nitrogen, creatinine, glucose, coagulation studies, and arterial or venous blood gas analysis as clinically indicated. Urine toxicology screening is rarely helpful because most hallucinogens are not detected on routine screens, amphetamine assays may be negative for hallucinogenic amphetamines such as MDMA, and distinguishing specific agents rarely changes management. Imaging should be guided by clinical suspicion and may include chest radiography for suspected aspiration, aortic pathology, or trauma, head CT for intracranial hemorrhage or lesions, and abdominal radiography if ingested drug packets are suspected.
Differential Considerations
The differential diagnosis includes hypoglycemia, meningitis, encephalitis, sepsis, intracranial hemorrhage or mass lesions, withdrawal syndromes (ethanol, sedative–hypnotics, baclofen), serotonin syndrome (particularly with co-ingestion of serotonergic agents), primary psychiatric illness including prolonged psychosis associated with LSD, chronic amphetamine or cocaine use, steroid-induced psychosis, and infectious or febrile seizures in hyperpyrexic children.
Prehospital Management
Management controversies include the choice between benzodiazepines, neuroleptics, or physical restraints for agitation. Benzodiazepines are generally preferred. Sedation may obscure symptoms and limit history but is often necessary for safe transport. Hyperthermic patients should be sedated rather than physically restrained, and cooling measures should be initiated early.
Initial Stabilization Approach
Management begins with airway, breathing, and circulation assessment. Aggressive cooling is required for hyperthermia. Establish IV access and provide isotonic fluids for dehydration or suspected rhabdomyolysis. In patients with altered mental status, check blood glucose and consider naloxone, dextrose, and thiamine as indicated.
Emergency Department Treatment
Supportive care is the mainstay. Cooling measures include cool mist and fans. Benzodiazepines are first-line therapy for agitation, anxiety, or autonomic instability. Paralysis with intubation may be required in severe cases, generally avoiding succinylcholine. Neuroleptics are rarely used because they may intensify hallucinogenic effects and lower the seizure threshold. Activated charcoal is generally not helpful due to rapid absorption and delayed presentation, but may be considered within 2–3 hours of ingestion in patients with a protected airway, especially for anticholinergic agents or ingested seeds. Patients should be placed in a quiet, calm environment. Maintain urine output at 2–3 mL/kg/hr and consider urine alkalinization when treating rhabdomyolysis.
Medication Options
Benzodiazepines such as diazepam 5–10 mg IV (pediatric dose 0.2–0.5 mg/kg) or lorazepam 1–4 mg IV/IM (pediatric dose 0.02–0.05 mg/kg) may be repeated as needed. Dextrose should be administered for hypoglycemia. Haloperidol 2.5–5 mg IV/IM may be used cautiously in adults for refractory agitation, but is generally avoided in children. Naloxone may be administered when opioid co-ingestion is suspected. Sodium bicarbonate infusion may be used for rhabdomyolysis to maintain urine alkalinity. Thiamine 100 mg IV or IM is recommended in at-risk patients.
Disposition And Follow-Up
Admission is indicated for severe intoxication, atypical or prolonged presentations, symptoms persisting longer than 12 hours, or prolonged agitation and hyperthermia with risk of rhabdomyolysis or organ damage. Most patients may be discharged after observation once asymptomatic and clinically stable. Suspected pediatric abuse or neglect requires referral to child protective services. Discharged patients should be advised to follow up with a primary care provider, psychiatrist, or substance use counseling service.
Clinical Pearls And Pitfalls
Hyperthermia must be recognized and treated immediately with aggressive temperature reduction. Violent or agitated patients require appropriate physical and chemical restraints to ensure safety. Serial examinations and vital sign monitoring, especially temperature, are essential. Do not assume clinical improvement once agitation subsides, as deterioration to severe toxicity may still occur.
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