DESCRIPTION

• Lysergic acid diethylamide (LSD) is colorless, odorless, and tasteless.
• Other hallucinogens with similar structure and toxic effects are kava-kava, mate, mescaline, morning glory, nutmeg, periwinkle, peyote, psilocin, psilocybin, and yohimbine.

FORMS AND USES

The psychedelic dose for LSD is 100 to 750 µg, for mescaline is 5 mg/kg, and for nutmeg about 5 to 10 g (1 tablespoon).

TOXIC DOSE

The lethal dose is unknown, but death has occurred rarely from hallucinogen overdose.

PATHOPHYSIOLOGY

• The psychedelic effect of hallucinogens is thought to be caused by agonistic actions at presynaptic serotonin receptors in the mid-brain.
• One hypothesis suggests that they prevent the inhibitory effects of serotonin, allowing increased neuronal activity and causing distortions of perception and thought.

EPIDEMIOLOGY

• Poisoning is common, and use of hallucinogens has increased in recent years.
• Death from hallucinogen abuse is rare and usually due to trauma or complications of hyperthermia, hypertension, or rhabdomyolysis.

CAUSES

• Poisoning usually results from intentional abuse.
• Child neglect or abuse should be considered in children under 1 year of age.

DRUG AND DISEASE INTERACTIONS

• A combination of lithium, fluoxetine, and LSD or a combination of fluoxetine and LSD has resulted in seizures.
• Hallucinogens are usually serotonergic compounds and may precipitate serotonin syndrome, especially if the patient is under treatment with another serotonergic compound such as a selective serotonin reuptake inhibitor (SSRI).

PREGNANCY AND LACTATION

• LSD and nutmeg. US FDA Pregnancy Category C. The drug exerts animal teratogenic or embryocidal effects, but there are no controlled studies in women, or no studies are available in either animals or women.
• Prolonged seizures can compromise the fetus via hypoxia and trauma.
• Mescaline has produced teratogenic effects in animals.

Section Outline:

• DESCRIPTION
• FORMS AND USES
• TOXIC DOSE
• PATHOPHYSIOLOGY
• EPIDEMIOLOGY
• CAUSES
• DRUG AND DISEASE INTERACTIONS
• PREGNANCY AND LACTATION

DIFFERENTIAL DIAGNOSIS

• Toxic causes of hallucinations include amphetamines, anticholinergics, high-dose corticosteroid, phencyclidine, peyote, psilocybin, mescaline, and several others.
• Nontoxic causes include CNS trauma, meningitis, AIDS-related illness, hypoglycemia, electrolyte imbalance, heat-related illness, hypoxia, alcohol withdrawal, or sedative-hypnotic withdrawal.

SIGNS AND SYMPTOMS

• Diagnosis is clinical, based primarily on a medical history and the exclusion of other causes in the hallucinating patient.
• Soon after ingestion, diaphoresis, mydriasis, dizziness, twitching, flushing, hyperreflexia, and hypertension develop.
• Psychosis can occur within 15 to 20 minutes; auditory and visual hallucinations can occur after 30 minutes; behavioral changes, emotional lability, euphoria or dysphoria, paranoia, and depersonalization can occur after several hours.

Vital Signs

Hypertension, hypotension, hyperthermia, tachycardia, and tachypnea may develop with any of these agents.

HEENT

• Mydriasis and blurred vision are common with all agents.
• Repeated visual illusions are common.

Dermatologic

Diaphoresis is common, and piloerection may occur.

Cardiovascular

Hypertension and tachycardia may occur.

Pulmonary

Bronchospasm develops rarely.

Gastrointestinal

Vomiting, diarrhea, salivation, and anorexia may develop.

Renal

Renal failure may develop rarely, due to rhabdomyolysis.

Fluids and Electrolytes

Metabolic acidosis may develop rarely, secondary to seizures.

Musculoskeletal

Rhabdomyolysis may develop rarely, secondary to seizures.

Neurologic

• Restlessness, incoordination, tremors, and ataxia may develop.
• Behavioral changes characterized by mild apprehension to panic and depersonalization may develop 2 to 12 hours after ingestion.
• Seizures, coma, and weakness are rare, but have been reported.

Reproductive

LSD causes uterine contractions.

PROCEDURES AND LABORATORY TESTS

Essential Tests

No tests are usually needed in asymptomatic or minimally symptomatic patients.

Recommended Tests

• Serum electrolytes, BUN, and creatinine levels are used to assess other causes of altered mental status, seizures, or cardiac effects.
• Urinalysis. Rhabdomyolysis or hypotension may produce renal injury.
• Arterial blood gases. Metabolic acidosis may develop with prolonged seizures.
• A urine drug screen is used in patients with hallucinations of unknown cause to determine other ingestant or causes of seizures and cardiac effects.
• Head CT, lumbar puncture, blood, and CSF cultures are ordered as needed to evaluate infection or cranial bleed as a cause of altered mental status.

Not Recommended Tests

Serum levels of hallucinogens are not clinically useful.

Section Outline:

• DIFFERENTIAL DIAGNOSIS
• SIGNS AND SYMPTOMS
  • Vital Signs
  • HEENT
  • Dermatologic
  • Cardiovascular
  • Pulmonary
  • Gastrointestinal
  • Renal
  • Fluids and Electrolytes
  • Musculoskeletal
  • Neurologic
  • Reproductive
• PROCEDURES AND LABORATORY TESTS
  • Essential Tests
  • Recommended Tests
  • Not Recommended Tests

• Treatment focuses on managing the airway and controlling activity associated with hallucinations, psychosis, or panic reaction.
• The dose and time of exposure must be determined for all substances involved.

DIRECTING PATIENT COURSE

The health-care provider should call the poison control center when:

• Seizures, coma, hyperthermia, hypotension, acidemia, or other severe effects are present.
• Toxic effects are not consistent with hallucinogen poisoning.
• Coingestant, drug interaction, or underlying disease presents an unusual problem.

The patient should be referred to a health-care facility when:

• Attempted suicide or homicide is possible.
• Patient or caregiver seems unreliable.
• Undesired effects develop.
• Coingestant, drug interaction, or underlying disease presents an unusual challenge.

Admission Considerations

Inpatient management is warranted for patients with persistent alteration in mental status or end-organ complications such as rhabdomyolysis or renal failure.

DECONTAMINATION

• Gastrointestinal decontamination is not usually recommended because a very small amount of LSD is needed to produce hallucination and it is rapidly absorbed.
• If another hallucinogen was ingested or coingestants are possible, one dose of activated charcoal (1-2 g/kg) without cathartic should be administered.

ANTIDOTES

There is no specific antidote available for hallucinogens.

ADJUNCTIVE TREATMENT

Hallucinogen-induced Agitation or Psychosis

• The patient is placed in a dimly lit room, offered counseling and companionship, and "talked down."
• A benzodiazepine familiar to the provider should be administered.
  • Diazepam. Adult dose is 5 to 10 mg intravenously; pediatric dose is 0.2 to 0.5 mg/kg intravenously; doses are repeated at 10-minute intervals and titrated to effect.
  • Lorazepam is an alternative. Adult dose is 1 to 2 mg intravenously; pediatric dose is 0.05 mg/kg; doses are repeated at 10-minute intervals and titrated to effect.
  • The airway is monitored closely.
  • A neuroleptic agent such as droperidol should be used only in refractory cases because neuroleptics may induce seizure by lowering seizure threshold.

Seizure

A patent airway is ensured and a benzodiazepine is administered for initial control in the same method described above for agitation. If seizures persist, phenytoin or phenobarbital may be added.

Hyperthermia

• Clothing should be removed, and intravenous infusion of isotonic crystalloid started; agitation must be controlled.
• Fluid losses may be severe and should be replenished until a urine output of 1 to 2 ml/kg/h is reached; the fluid infusion needs to be monitored carefully to avoid overload.
• Cooling fans and wet sheets are effective, especially in a dry climate.
• Application of ice may be more effective in humid climates.
• The core temperature should be monitored frequently, and cooling should be discontinued when body temperature decreases to 39°C.

Section Outline:

• DIRECTING PATIENT COURSE
  • Admission Considerations
• DECONTAMINATION
• ANTIDOTES
• ADJUNCTIVE TREATMENT
  • Hallucinogen-induced Agitation or Psychosis
  • Seizure
  • Hyperthermia

EXPECTED COURSE AND PROGNOSIS

• Effects usually peak within several hours and then abate over 24 hours or more.
• Patients with repeated seizures or hyperthermia are more likely to die or sustain permanent neurologic injury.
• Possible complications include renal failure and CNS injury due to prolonged seizures.
• Flashbacks are generally uncommon, but they may occur in chronic, frequent LSD abusers.

DISCHARGE CRITERIA/INSTRUCTIONS

• From the emergency department
  • Asymptomatic patients may be discharged after 6 hours of observation.
  • The patient must be cautioned that the continued use of drugs may precipitate flashbacks and should be avoided.
  • The patient should be referred for substance abuse treatment.
• From the hospital
  • Patients may be discharged to a responsible friend or family member, after complications have resolved and vital signs have returned to normal.
  • The patient should be referred for substance abuse treatment.

PATIENT EDUCATION

Patients should be cautioned that drug use may precipitate flashbacks and should be avoided.

Section Outline:

• EXPECTED COURSE AND PROGNOSIS
• DISCHARGE CRITERIA/INSTRUCTIONS
• PATIENT EDUCATION

DIAGNOSIS

• Before attributing hallucinations to LSD, other causes must be excluded.
• Standard urine drug screening may not detect LSD.

TREATMENT

• Large amounts of benzodiazepines may be needed to control agitation.
• Prompt seizure control is mandatory; general anesthesia or neuromuscular paralysis and EEG monitoring may be required.

Section Outline:

• DIAGNOSIS
• TREATMENT

Poisoning by psychotropic agents: psychodysleptics (hallucinogens).

See Also: SECTION II, Hyperthermia and Seizures chapters.

RECOMMENDED READING

Aaron CK, Ferm RP. Lysergic acid diethylamide and other psychedelics. In: Goldfrank LR, Flomenbaum NE, Lewin NA, et al., eds. Goldfrank's toxicologic emergencies, 6^th ed. Norwalk, CT: Appleton & Lange, 1998.

Lewin NA, Howland MA, Goldfrank LR. Herbal preparations. In: Goldfrank LR, Flomenbaum NE, Lewin NA, et al.; eds. Goldfrank's toxicologic emergencies, 6^th ed. Norwalk, CT: Appleton & Lange, 1998.

Author: Robin Millin

Reviewer: Luke Yip