Amphetamine Poisoning

[Section Outline]

Description
Etiology

Author:

James W.Rhee

Description

Increased release of norepinephrine, dopamine, and serotonin
Decreased catecholamine reuptake
Direct effect on α- and β-adrenergic receptors

Etiology

Prescription drugs:
- Amphetamine (Benzedrine)
- Dextroamphetamine (Dexedrine)
- Diethylpropion (Tenuate)
- Fenfluramine (Pondimin)
- Methamphetamine
- Methylphenidate (Ritalin)
- Phenmetrazine (Preludin)
- Phentermine
“Designer drugs”:
- Variants of illegal parent drugs
- Often synthesized in underground labs
- “Crystal,” “Ice”:
  - Crystalline methamphetamine hydrochloride
  - Smoked, insufflated, or injected
  - Rapid onset; duration several hours
- “Crank”
- “Ecstasy” (3,4-methylenedioxymethamphetamine, MDMA, XTC, E, Molly):
  - Often used at dances and “rave” parties
  - Dehydration can lead to hyperthermia, hyponatremia, fatality
- MDA (3,4-methylenedioxyamphetamine)
- Methcathinone (“cat,” “Jeff,” “mulka”):
  - Derivative of cathinone, found in the evergreen tree Catha edulis
  - Frequently synthesized in home labs
  - Does not show up on urine toxicology screens
- Mephedrone
  - May be contained in “bath salts”

Diagnosis ⬆ ⬇

[Section Outline]

Signs and Symptoms
Essential Workup
Diagnostic Tests & Interpretation
Differential Diagnosis

Signs and Symptoms

CNS:
- Agitation
- Delirium
- Hyperactivity
- Tremors
- Dizziness
- Mydriasis
- Headache
- Choreoathetoid movements
- Hyperreflexia
- Cerebrovascular accident
- Seizures and status epilepticus
- Coma
Psychiatric:
- Euphoria
- Increased aggressiveness
- Anxiety
- Hallucinations (visual, tactile)
- Compulsive repetitive actions
Cardiovascular:
- Palpitations
- Hypertensive crisis
- Tachycardia or (reflex) bradycardia
- Dysrhythmias (usually tachydysrhythmias)
- Cardiovascular collapse
Other:
- Rhabdomyolysis
- Myoglobinuria
- Acute renal failure
- Anorexia
- Diaphoresis
- Disseminated intravascular coagulation (DIC)

History

Determine the type, amount, timing, and route of amphetamine exposure
Assess for possible coingestions
Evaluate for symptoms of end organ injury:
- Chest pain
- Shortness of breath
- Headache, confusion, and vomiting

Physical Exam

Common findings include:
- Agitation
- Tachycardia
- Diaphoresis
- Mydriasis
Severe intoxication characterized by:
- Tachycardia
- HTN
- Hyperthermia
- Agitated delirium
- Seizures
- Diaphoresis
Hypotension and respiratory distress may precede cardiovascular collapse
Evaluate for associated conditions:
- Cellulitis and soft tissue infections
- Diastolic cardiac murmurs or unequal pulses
- Examine carefully for trauma
- Pneumothorax from inhalation injury
- Focal neurological deficits

Essential Workup

Vital signs:
- Temperature >40°C:
  - Core temperature recording essential
  - Peripheral temperature may be cool
  - Indication for urgent cooling
  - Ominous prognostic sign
- BP:
  - Severe hypertension can lead to cardiac and neurologic abnormalities.
  - Late in course, hypotension may supervene due to catecholamine depletion
ECG:
- Signs of cardiac ischemia
- Ventricular tachydysrhythmias
- Reflex bradycardia

Diagnostic Tests & Interpretation

Lab

Urinalysis:
- Blood
- Myoglobin
Electrolytes, BUN/creatinine, glucose:
- Hypoglycemia may contribute to altered mental status
- Acidosis may accompany severe toxicity
- Rhabdomyolysis may cause renal failure
- Hyperkalemia—life-threatening consequence of acute renal failure
Coagulation profile to monitor for potential DIC:
- INR, PT, PTT, platelets
Creatine phosphokinase (CPK):
- Markedly elevated in rhabdomyolysis
Urine toxicology screen:
- For other toxins with similar effects (e.g., cocaine)
- Some amphetamine-like substances (e.g., methcathinone) may not be detected
Aspirin and acetaminophen levels if suicide attempt is a possibility
Arterial blood gas (ABG)

Imaging

Chest radiograph:
- Adult respiratory distress syndrome
- Noncardiogenic pulmonary edema
Head CT for:
- Significant headache
- Altered mental status
- Focal neurologic signs
- For subarachnoid hemorrhage, intracerebral bleed

Diagnostic Procedures/Surgery

Lumbar puncture for:

Suspected meningitis (headache, altered mental status, hyperpyrexia)
Suspected subarachnoid hemorrhage and CT normal

Differential Diagnosis

Sepsis
Thyroid storm
Serotonin syndrome
Neuroleptic malignant syndrome
Pheochromocytoma
Subarachnoid hemorrhage
Drugs that cause delirium:
- Anticholinergics:
  - Belladonna alkaloids
  - Antihistamines
- Tricyclic antidepressants
- Cocaine
- Ethanol withdrawal
- Sedative/hypnotic withdrawal
- Hallucinogens
- Phencyclidine
Drugs that cause HTN and tachycardia:
- Sympathomimetics
- Anticholinergics
- Ethanol withdrawal
- Phencyclidine
- Caffeine
- Phenylpropanolamine
- Ephedrine
- Monoamine oxidase inhibitors
- Theophylline
- Nicotine
Drugs that cause seizures:
- Carbon monoxide
- Carbamazepine
- Cyanide
- Cocaine
- Cholinergics (organophosphate insecticides)
- Camphor
- Chlorinated hydrocarbons
- Ethanol withdrawal
- Sedative/hypnotic withdrawal
- Isoniazid
- Theophylline
- Hypoglycemics
- Lead
- Lithium
- Local anesthetics
- Anticholinergics
- Phencyclidine
- Phenothiazines
- Phenytoin
- Propoxyphene
- Salicylates
- Strychnine

Treatment ⬆ ⬇

[Section Outline]

Prehospital
Initial Stabilization/Therapy
ED Treatment/Procedures
Medication

Prehospital

Patient may be uncooperative or violent
Secure IV access
Protect from self-induced trauma

Initial Stabilization/Therapy

ABCs
Establish IV 0.9% NS access
Cardiac monitor
Naloxone, dextrose (or Accu-Chek), and thiamine if altered mental status

ED Treatment/Procedures

Decontamination:
- Administration of activated charcoal
- Whole-bowel irrigation with polyethylene glycol solution for body packers
Hypertensive crisis:
- Initially administer benzodiazepines if agitated
- α-Blocker (phentolamine) as second-line agent
- Nitroprusside for severe, unresponsive hypertension
- Avoid β-blockers, which may exacerbate hypertension
Agitation, acute psychosis:
- Administer benzodiazepines
Hyperthermia:
- Benzodiazepines if agitated
- Active cooling if temperature >40°C:
  - Tepid water mist
  - Evaporate with fan
- Paralysis:
  - Indicated if muscle rigidity and hyperactivity contributing to persistent hyperthermia
  - Nondepolarizing agent (e.g., vecuronium)
  - Avoid succinylcholine
  - Intubation; mechanical ventilation
- Apply cooling blankets
Rhabdomyolysis:
- Administer benzodiazepines
- Hydrate with 0.9% NS
- Maintain urine output at 1-2 mL/min
- Hemodialysis (if acute renal failure and hyperkalemia occur)
Seizures:
- Maintain airway
- Administer benzodiazepines
- Phenobarbital if unresponsive to benzodiazepines
- Phenytoin contraindicated
Hypotension:
- May be late finding due to catecholamine depletion
- Initially bolus with isotonic crystalloid solution
- If no response, administer norepinephrine
- Dopamine may not be effective

Medication

Activated charcoal: 1-2 g/kg up to 100 g PO
Dextrose: D₅₀W 1 amp: 50 mL or 25 g (peds: D₂₅W 2-4 mL/kg) IV
Diazepam (benzodiazepine): 5-10 mg (peds: 0.2-0.5 mg/kg) IV
Lorazepam (benzodiazepine): 2-6 mg (peds: 0.03-0.05 mg/kg) IV
Nitroprusside: 1-8 mcg/kg/min IV (titrated to BP)
Phenobarbital: 15-20 mg/kg IV at 25-50 mg/min until cessation of seizure activity
Phentolamine: 1-5 mg IV over 5 min (titrated to BP)
Vecuronium: 0.1 mg/kg IVP

Follow-Up ⬆ ⬇

[Section Outline]

Disposition
Follow-up Recommendations

Disposition

Admission Criteria

Hyperthermia
Persistent altered mental status
Hypertensive crisis
Seizures
Rhabdomyolysis
Persistent tachycardia

Discharge Criteria

Asymptomatic after 6-hr observation
Absence of the above admission criteria

Follow-up Recommendations

Patients may need referral for chemical dependency rehab and detoxification

Pearls and Pitfalls ⬆ ⬇

Admit patients with severe or persistent symptoms
Monitor core temperature:
- Hyperthermia >40°C may be life threatening
- Treat with aggressive sedation and active cooling
- Recognize rhabdomyolysis and hyperkalemia
- Avoid physical restraints in agitated patients if possible
Consider associated emergency conditions:
- Patients with chest pain should be evaluated for acute coronary syndromes and treated accordingly
- Consider infection in altered patients with fever and history of IV drug use
- Methamphetamineabuse frequently associated with traumatic injury
Benzodiazepines are first-line therapy in symptomatic methamphetamine intoxication
Some newer stimulant drugs-of-abuse are chemically similar to amphetamines

Additional Reading ⬆ ⬇

CarvalhoM, CarmoH, CostaVM, et al. Toxicity of amphetamines: An update . Arch Toxicol. 2012;86:1167-1231.
CourtneyKE, RayLA. Clinical neuroscience of amphetamine-type stimulants: From basic science to treatment development . Prog Brain Res. 2016;223:295-310.
GraySD, FatovichDM, McCoubrieDL, et al. Amphetamine-related presentations to and inner-city tertiary emergency department: A prospective evaluation . Med J Aust. 2007;186:336.
ProsserJM, NelsonLS. The toxicology of bath salts: a review of synthetic cathinones . J Med Toxicol. 2012;8:33-42.

See Also (Topic, Algorithm, Electronic Media Element)

Codes ⬆

ICD9

969.72 Poisoning by amphetamines
969.73 Poisoning by methylphenidate
969.79 Poisoning by other psychostimulants
969.70 Poisoning by psychostimulant, unspecified

ICD10

T43.601A Poisoning by unsp psychostim, accidental, init
T43.621A Poisoning by amphetamines, accidental (unintentional), init
T43.631A Poisoning by methylphenidate, accidental, init
T43.691A Poisoning by oth psychostim, accidental, init

SNOMED

45775001 Poisoning by amphetamine (disorder)
216559001 Accidental poisoning by amphetamine (disorder)
291258000 Accidental ecstasy poisoning (disorder)
291242003 Amphetamine poisoning of undetermined intent (disorder)

section name header

Basics ⬇

Diagnosis ⬆ ⬇

History

Physical Exam

Lab

Imaging

Diagnostic Procedures/Surgery

Treatment ⬆ ⬇

Follow-Up ⬆ ⬇

Admission Criteria

Discharge Criteria

Pearls and Pitfalls ⬆ ⬇

Additional Reading ⬆ ⬇

Codes ⬆