Methamphetamine

Aka: Methamphetamine, Methamphetamine Hydrochloride, Methamphetamine Overdose, Methamphetamine Intoxication, Methamphetamine Dependence, Methamphetamine Abuse, Yaba, Crystal Meth, Desoxyn

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II. Definition

  1. Stimulant drug of abuse similar to Cocaine
  2. Manufactured from Pseudoephedrine

III. Preparations

  1. Methamphetamine
    1. Street Names: Speed, Meth, Chalk
    2. Desoxyn (Methamphetamine)
      1. FDA approved for ADHD and Obesity
      2. Risk of diversion and misuse (crushed and snorted or injected)
  2. Methamphetamine Hydrochloride (crystalline)
    1. High potency agent that is typically smoked
    2. Street Names: Crystal Meth, Glass, Ice, Crank
    3. Crystal Meth is clear, white or yellow and larger in size
    4. Ice is clear, similar to crushed ice chunks
    5. Crank is white powder (snorted or dissolved in water/Alcohol and injected)
    6. Booty bumping is meth placed in Rectum for rapid absorption
    7. Love Rocket is meth placed in vagina for rapid absorption
  3. Yaba (Methamphetamine and Caffeine)
    1. More common in southeast Asia, but growing use in the U.S.
    2. Brightly colored tablets that are swallowed

IV. Epidemiology

  1. Prevalence: 2.8% of U.S. adults 18 to 26 years of age
    1. More common in those living in Western United States
    2. Iritani (2007) Addiction 102:1102-13 [PubMed]
  2. Ethnicity
    1. Most Methamphetamine users are white (0.7% of white population)
    2. Pacific islanders (e.g. Hawaii) and Native Americans (2.2 to 1.7% of these populations)
  3. Other populations with higher use percentages of Methamphetamine Abuse
    1. Homosexual men

V. Effects

  1. Stimulant agent similar to Cocaine
    1. Sympathomimetic amine stimulates a1 and B1 post-synaptic receptors
    2. Inhibits presynaptic reuptake of Norepinephrine, Dopamine and Serotonin
  2. Used orally, intranasally, intravenously (dissolved in water or Alcohol), smoked or inserted rectally
    1. Rapid effects ("rush" or "flash") with injection or when smoked
    2. Multiple doses are often used to sustain the otherwise transient effects
      1. Results in binge-crash pattern of use
  3. Effect: Initial
    1. Immediate rush-Sensation that lasts for minutes (limited to smoked or IV forms)
    2. Euphoria
    3. Hightened alertness
    4. Increased energy
    5. Increased libido (and associated high risk sexual behavior)
    6. Diminshed appetite
  4. Effect: Later as drug wears off
    1. Prolonged sleep or sedation
    2. Dysphoria
  5. Contaminants
    1. Methamphetamine is frequently contaminated with other agents (e.g. Fentanyl)

VI. Pharmacokinetics

  1. Half-Life: 10-12 hours
  2. Rapid oral absorption
  3. Metabolized by liver via Cytochrome P2D6 system
  4. Much longer duration of action than Cocaine
  5. Lethal dose as low as 1.5 mg/kg orally in some cases

VII. Pathophysiology

  1. High potential for abuse and dependence
  2. Enhances mood via stimulation of Dopamine release
  3. Nerve terminals recede in response to Methamphetamine
    1. Affects Dopamine and Serotonin nerve endings
    2. Effects may be permanent
      1. Imaging shows prolonged brain structural and functional changes long after cessation

VIII. Adverse Effects: Acute

  1. Most related deaths occur from homicides, Suicides and accidents following use
  2. Similar to other adrenergic agents (e.g. Amphetamine)
    1. See Sympathomimetic Toxicity
    2. Tachycardia
    3. Hypertension
    4. Hyperthermia
    5. Tachypnea
    6. Serotonin Syndrome
  3. Agitated Delirium
    1. Agitation
    2. Psychosis
    3. Rhabdomyolysis
  4. Other vascular and neurologic effects
    1. Arrythmias
    2. Cerebrovascular Accident
    3. Myocardial Infarction
    4. Seizure

IX. Adverse Effects: Chronic

  1. Stimulant Use Disorder
  2. Irreversible Neuronal destruction
    1. Memory Loss
    2. Learning Impairment
    3. Motor slowing
  3. Psychiatric Changes
    1. Worsening Mood Disorders
      1. Anxiety Disorder
      2. Depression with increased Suicidal Ideation
    2. Psychosis (esp. paranoia, Delusions, Hallucinations)
      1. Associated with doses >50 mg in adults
    3. Violent Behavior
  4. Premature aging effect
  5. Chronic Malnutrition and associated Anorexia, weight loss
  6. Skin Abscesses (related to skin-picking behaviors)
  7. Severe Tooth Decay ("meth mouth")
    1. Untreated Tooth Decay in more than half of Methamphetamine users
  8. Cardiomyopathy
    1. Presents with severely reduced ejection fraction (mean 19%) with global hypokinesis in a young patient
    2. Results from Catecholamine related systemic effects, as well as Methamphetamine direct toxic effects
    3. Ejection fraction may return to normal after Methamphetamine cessation and maintained sobriety
    4. Voskoboinik (2016) Intern Med J 46(6): 723-7 +PMID:26929061 [PubMed]
  9. Mortality
    1. Methamphetamine related deaths have increased five fold between 2011 and 2018
      1. Han (2021) JAMA Psychiatry 78(5):564-7 [PubMed]

X. Adverse Effects: Pregnancy

  1. Placental Abruption
  2. Fetus
    1. Intrauterine Growth Retardation
    2. Prematurity
    3. Cleft Lip and Palate
    4. Heart defects
  3. Newborn withdrawal
    1. Abnormal sleep or food intake
    2. Tremors
  4. Infant
    1. Methamphetamine is secreted in Breast Milk

XI. Labs

  1. See Sympathomimetic Toxicity
  2. See Unknown Ingestion for toxicology labs
  3. Comprehensive metabolic panel
  4. Serum Lactic Acid
  5. Venous Blood Gas
  6. Creatinine phosphokinase
  7. Drug Screening
    1. Urine Drug Screen positive for 48 hours after use
    2. Hair analysis detects Methamphetamines
    3. Meconium testing is preferred for Newborn Screening
      1. Positive for Methamphetamine use in the second half of pregnancy

XII. Differential Diagnosis

  1. Heat Stroke
  2. Thyrotoxicosis (Hyperthyroidism)
  3. Pheochromocytoma
  4. Serotonin Syndrome
  5. Drug Overdose
    1. Other Sympathomimetic Toxicity (e.g. Cocaine, bath salts)
    2. TheophyllinePoisoning
    3. Salicylate Poisoning
      1. Metabolic Acidosis with Anion Gap
    4. Anticholinergic Poisoning
      1. Anhidrosis (dry) as opposed to diaphoresis in SympathomimeticPoisoning

XIII. Management: Acute Toxicity

  1. See Unknown Ingestion for general approach including labs
  2. See Sympathomimetic Toxicity
    1. Approach for Sympathomimetics is similar for most Sympathomimetic agents
  3. Gastric Decontamination (not indicated unless early presentation after ingestion, or body packing accident)
    1. Consider Gastric Lavage with Activated Charcoal if Methamphetamine was ingested immediately prior to presentation
  4. Sedation
    1. See Agitated Delirium
    2. Benzodiazepines are preferred first line (repeat every 10 minutes as needed)
      1. Lorazepam 4 mg IV
      2. Diazepam 5-10 mg IV
    3. Although Antipsychotics may be considered (e.g. Zyprexa, Haloperidol), risk of QTc Prolongation and hyperthermia
      1. Haloperidol 0.025 to 0.05 mg/kg up to 10 mg IM/IV and may repeat in 15-30 minutes
  5. Hypertensive Crisis
    1. Consider Nitroprusside or Phentolamine for Refractory Hypertension
  6. Hyperthermia
    1. Aggressive Cooling
    2. Benzodiazepines
    3. RSI and Endotracheal Intubation

XIV. Management: Chemical Dependency Treatment

  1. Chemical Dependency Program (e.g. Matrix Model)
  2. Contingency management program with rewards for patients with negative Urine Drug Screens
  3. Medications which may offer benefit
    1. Fluoxetine may reduce short-term cravings
    2. Imipramine improves compliance with therapy
    3. Mirtazipine (Remeron) may decrease use
    4. Bupropion with mixed results
  4. References
    1. Cretzmeyer (2003) J Subst Abuse Treat 24: 267-77 [PubMed]
    2. Colfax (2011) Arch Gen Psychiatry 68(11):1168-75 [PubMed]
    3. Elkashef (2008) Neuropsychopharmacology 33(5): 1162-70 [PubMed]

XV. Associated Conditions (related to demographics of Methamphetamine use)

  1. See Intravenous Drug Abuse
  2. Human Immunodeficiency Virus (HIV Infection)
  3. Hepatitis C Infection
  4. Criminality
  5. Hazardous environment
    1. Methamphetamine produces 6 pounds of toxic waste for every 1 pound of drug
    2. Methamphetamine lab explosions are not uncommon

XVI. Complications: Class effect of stimulant Drugs of Abuse

  1. See Sympathomimetic Toxicity
  2. See chronic adverse effects listed above

XVII. Resources

  1. National Institute on Drug Abuse: Methamphetamine
    1. http://www.drugabuse.gov/drugpages/methamphetamine.html

XVIII. References

  1. Moore, Behar, Claudius and Farrah in Herbert (2018) EM:Rap 18(5):11-2
  2. Boyer and Hernon in Traub and Burns (2015) Methamphetamine Intoxication, UpToDate, accessed 1/10/2017
  3. Tomaszewski (2021) Crit Dec Emerg Med 35(11): 28
  4. (2004) Med Lett Drugs Ther 46:62-3 [PubMed]
  5. Klega (2018) Am Fam Physician 98(2): 85-92 [PubMed]
  6. Winslow (2007) Am Fam Physician 76(8):1169-76 [PubMed]

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