Heroin

Epidemiology

  • Common drug used in IVDA

Pharmacology

  • Heroin is diacetylmorphine
    • Higher lipid solubility than morphine -> crosses blood-brain barrier more readily than morphine

Adverse Effects

  • Acute Hypoventilation (see [[Acute Hypoventilation]])
    • Treatment: naloxone
  • Acute Lung Injury-ARDS (see [[Acute Lung Injury-ARDS]])
    • Epidemiology
      • Probably the most common drug-induced pulmonary disease worldwide
      • May occur with first use of heroin
      • Probably dose-related (although exact dose is usually unknown)
      • 40% of acute overdoses have heroin-induced pulmonary edema
    • Possible Physiologic Mechanisms
      • Direct toxic effect on alveolar-capillary membrane -> increased alveolar-capillary membrane permeability
      • Neurogenic response to CNS injury
      • Allergic or hypersensitivity reaction
      • Acute hypoxic effect on alveolar-capillary membrane -> secondary increase in alveolar-capillary membrane permeability
        • However, other agents that depress the respiratory center (barbiturates) rarely induce pulmonary edema
    • Diagnosis
      • ABG: metabolic and respiratory acidosis
      • CXR/Chest CT: bilateral alveolar infiltrates
    • Clinical
      • Dyspnea usually occurs within minutes of drug injection (although some cases may occur even hours-days later)
      • 50% of cases may have complicating aspiration pneumonia -> aspiration should be suspected in cases where infiltrates do not clear within 24-48 hrs
    • Treatment
      • Supportive
      • Avoid corticosteroids (especially in setting of suspected aspiration
      • Antibiotics: if aspiration is suspected
    • Prognosis
      • Decreased DLCO on PFT’s may be persistently observed even after infiltrates have cleared
  • Recurrent Aspiration Pneumonia with Bronchiectasis (see [[Aspiration Pneumonia]] and [[Bronchiectasis]])
    • Epidemiology: cases have been reported in chronic heroin users
    • Physiology: probably related to recurrent aspiration
  • Necrotizing Bronchitis (see [[Aspiration Pneumonia]])
    • Epidemiology: cases have been reported in chronic heroin users
    • Physiology: probably related to recurrent aspiration
  • Talc/Foreign Body Granulomatosis (see [[Foreign Body Granulomatosis]])
    • Epidemiology: seen in chronic heroin IVDA

References

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