DESCRIPTION

Heroin is an addictive drug of abuse that stimulates opioid receptors.

FORMS AND USES

• Heroin, also known by the street names of black tar, china white, crank, "H," or horse, is used intravenously, intranasally, or by smoking; anal exposure may occur in an attempt to conceal the drug.
• Heroin is also mixed with cocaine or amphetamine (speedballing).
• Heroin is a U.S. Drug Enforcement Agency Schedule I substance; it has no accepted therapeutic use in the United States.
• See also SECTION II, Body Packer/Body Stuffer chapter.

TOXIC DOSE

• The toxic dose cannot be estimated because of variation in heroin potency and tolerance in the user.
• Small amounts may produce respiratory depression in naive users.
• The street drug contains variable amounts of the active drug (generally 21%-60%).

PATHOPHYSIOLOGY

• Primary effects in overdose are caused by binding to µ, kappa-, and sigma- opioid receptors, producing CNS and respiratory depression.
• Direct pulmonary toxicity results in noncardiogenic pulmonary edema.
• Some elements of toxicity may result from:
  • Adulterants such as amphetamine, cocaine, dextromethorphan, quinine, scopolamine, strychnine, thiamine, or vinegar.
  • Bacterial or viral contamination.
  • Physical impurities.
• "Cotton fever" refers to a febrile reaction following injection of drug filtered through cotton balls.

EPIDEMIOLOGY

• Poisoning is common.
• Toxic effects following exposure are typically moderate to severe.
• Death occurs in patients with severe respiratory depression.

CAUSES

Overdose usually occurs during abuse and results from an unknown concentration of drug or from resumption of prior dose after a period of abstinence and loss of acquired tolerance.

DRUG INTERACTIONS

Heroin has an additive effect with drugs that produce CNS or respiratory depression.

PREGNANCY AND LACTATION

• US FDA Pregnancy Category B. Animal studies indicate no fetal risk, and there are no controlled human studies, or animal studies show an adverse fetal effect but well-controlled studies in pregnant women do not.
• Heroin enters breast milk and may produce addiction in the fetus or infant.

Section Outline:

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

DIFFERENTIAL DIAGNOSIS

• Drugs that produce CNS and respiratory depression include benzodiazepines, barbiturates, neuroleptics, alcohol, antidepressants, and other opioids, as well as many other medications.
• Other agents that produce miosis include organophosphate insecticides, carbamates, and nicotine, among others.
• Conditions that depress mental status include postictal states, hypoglycemia, cerebrovascular accident, and respiratory arrest, among others.

SIGNS AND SYMPTOMS

• Rapid onset of miosis, coma, apnea, and, possibly, pulmonary edema.
• Following ingestion, however, toxic effects may be delayed.

Vital Signs

Bradycardia, hypotension, apnea, or hyper- or hypothermia may occur.

HEENT

Pinpoint pupils occur, but they may be dilated after severe hypoxia or acidosis.

Dermatologic

Needle tracks are usually present in intravenous abusers.

Cardiovascular

Dysrhythmia from hypoxia or adulterants may occur.

Pulmonary

• Noncardiogenic pulmonary edema usually presents within 2 hours of intravenous use, but may be delayed 24 to 72 hours with smoking or ingestion.
• Talc from impurities can cause granulomatous reactions in the lung following intravenous use.

Gastrointestinal

• Decreased bowel sounds and functional bowel obstruction may develop.
• Constipation may occur in chronic users.

Renal

Rhabdomyolysis may cause acute renal failure.

Musculoskeletal

Rhabdomyolysis from localized muscle compression may occur if prolonged coma develops.

Neurologic

• CNS depression with lethargy or coma may occur.
• Seizures may occur.

PROCEDURES AND LABORATORY TESTS

Essential Tests

Pulse oximetry is used to monitor for hypoxia; persistent hypoxia after naloxone may indicate insufficient naloxone, another toxicologic agent, or pulmonary edema.

Recommended Tests

• Serum electrolytes, BUN, and creatinine are measured in symptomatic patients to assess other causes of CNS depression.
• ECG, serum acetaminophen, and aspirin levels in an overdose setting detect occult overdose.
• Head CT and lumbar puncture are used as needed to evaluate causes of altered mental status.
• Cultures of blood, urine, wounds, and sputum are ordered as clinically indicated to detect complications from intravenous drug abuse.
• Chest radiography is ordered in patients with respiratory signs or symptoms to detect pulmonary edema.
• Urine test for opioids may show positive results after ingestion of foods containing poppy seeds.

Section Outline:

• DIFFERENTIAL DIAGNOSIS
• SIGNS AND SYMPTOMS
  • Vital Signs
  • HEENT
  • Dermatologic
  • Cardiovascular
  • Pulmonary
  • Gastrointestinal
  • Renal
  • Musculoskeletal
  • Neurologic
• PROCEDURES AND LABORATORY TESTS
  • Essential Tests
  • Recommended Tests

• Treatment should focus on airway management, naloxone administration, and decontamination, if needed.
• Dose and time of exposure should be determined for all substances involved.

DIRECTING PATIENT COURSE

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

• Persistent apnea or hypotension, or other severe effects occur.
• Toxic effects are not consistent with heroin.
• Coingestant, drug interaction, or underlying disease presents an unusual problem.

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

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

Admission Considerations

Inpatient treatment is warranted for patients who develop pulmonary edema or who have persistent respiratory, cardiac, or CNS effects despite naloxone therapy.

DECONTAMINATION

Out of Hospital

Emesis should not be induced because CNS depression may develop abruptly.

In Hospital

• Decontamination after intravenous injection or inhalation is not needed.
• Oral ingestion is classified as a "body stuffer" or "body packer."

ANTIDOTES

Naloxone

• Indications
  • Naloxone is used for respiratory depression from known opioid overdose. (See SECTION III, Naloxone chapter, for information on the use of naloxone for less severe manifestations.)
  • It may be prudent to observe patients who can maintain their airway and oxygenation rather than treat them, so that discharge may occur without concern for recurrent opioid toxicity.
• Contraindications. Documented naloxone allergy
• Dose and method of administration
  • A dose of 2.0 mg intravenous push is administered and the response is observed.
  • If no response, dose is repeated in 2.0 mg increments to a total dose of 10 mg.
  • Although less desirable, naloxone may also be administered by endotracheal, intramuscular, intralingual, intraosseous, or subcutaneous injection.
  • If reversal response occurs, patients should be observed for 4 hours after final dose.
  • Patients with persistent or recurrent effects may be treated with constant infusion of naloxone.

Nalmefene

Nalmefene has been proposed for use when prolonged reversal of opioid effect is desired.

Dose and Method of Administration

• Starting dose of 0.5 mg intravenous push is administered; if no effect, an additional 1 mg is given.
• Higher doses of nalmefene appear to give prolonged activity; 1.5 mg of nalmefene blocks opioid activity for up to 8 hours.
• If repeat dosing is required, the patient should be admitted.

ADJUNCTIVE THERAPIES

• Pulmonary edema
  • Endotracheal intubation is often needed to provide adequate ventilation and oxygenation.
  • If adequate oxygenation cannot be maintained on 60% FiO₂, positive end-expiratory pressure or continuous positive airway pressure should be considered.
  • Care should be taken to avoid fluid overload.
• Hypotension
  • The primary treatment is correction of narcotic effects and dysrhythmia.
  • In addition, 10 to 20 ml/kg 0.9% saline may be administered, the patient placed in Trendelenburg position, and, if needed, a vasopressor is administered.
• Seizures
  • Seizures should be controlled with benzodiazepine, followed by phenobarbital or phenytoin, if needed.
• Complications of intraarterial injection may require heparin, vasodilators, and/or fibrinolysis; intraarterial reserpine use also has been reported.

Section Outline:

• DIRECTING PATIENT COURSE
  • Admission Considerations
• DECONTAMINATION
  • Out of Hospital
  • In Hospital
• ANTIDOTES
  • Naloxone
  • Nalmefene
• ADJUNCTIVE THERAPIES

PATIENT MONITORING

CNS, cardiovascular, and respiratory functions should be monitored continuously.

EXPECTED COURSE AND PROGNOSIS

• Complete recovery from hypoxia is expected if its duration is short.
• Sequelae of hypoxia may occur if apnea develops.
• Sequelae of intravenous drug abuse are common: endocarditis, abscess, human immunodeficiency virus, sepsis, hepatitis, and tetanus.

DISCHARGE CRITERIA/INSTRUCTIONS

• From the emergency department
  • Patients in whom toxic effects abate may be discharged following decontamination and observation for 4 hours beyond the last dose of naloxone.
  • Psychiatric evaluation and substance abuse counseling, if needed, should be obtained.
• From the hospital. Patients may be discharged after resolution of pulmonary edema and other complications such as rhabdomyolysis.

Section Outline:

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

Heroin is frequently mixed with scopolamine or other anticholinergics, which may mask opioid toxicity.

TREATMENT

• The patient must be observed beyond the expected duration of action of naloxone because respiratory depression may recur.
• The onset of pulmonary edema may be delayed for 24 to 72 hours.

Poisoning by analgesics, antipyretics, and antirheumatics: heroin.

See Also: SECTION II, Body Packers and Body Stuffers, Hypotension, and Seizure chapters; and SECTION III, Naloxone and Nalmephene, and Whole-Bowel Irrigation chapters.

RECOMMENDED READING

Duberstein JL, Kaufman DM. A clinical study of an epidemic of heroin intoxication and heroin-induced pulmonary edema. Am J Med 1971;51:704-714.

Harrison DW, Walls RM. "Cotton fever": a benign febrile syndrome in intravenous drug abusers. J Emerg Med 1990;8:135-139.

Author: Steven A. Seifert

Reviewer: Richard C. Dart