Heroin Intoxication

Basics

Heroin is a semisynthetic derivative of opium. The opioid family includes the following:

General
- 23 years of age: mean age of 1st use (2012)
- ~50% of those who have used an opioid pain reliever for nonmedical uses state they obtained it for free from a friend or relative.
- Nonmedical use of opioid pain relievers can lead to eventual injection heroin use.
Neonatal
- Fetal exposure commonly involves polysubstance abuse.
- 60–80% of heroin-exposed infants develop withdrawal—dependent on maternal dosing and length of use.
Adolescents
- Most use experimentally or intermittently; few become addicted and use daily.
- Use of opioid analgesics has increased dramatically over the last 10 years and has become more common than heroin use.
- Most common substances were oxycodone, hydrocodone, and methadone
Overdose
- Up to 1/3 of heroin users experience nonfatal overdose.
- Most occur in the home and with other people present.
- Risk factors include length of injecting history, concurrent use of CNS depressants, recent completion of substance abuse program, and recent release from prison.
Deaths
- Most heroin deaths occur when drug is administered IV.
- Most deaths in patients in their late 20s or 30s, with significant drug dependence
- Males are 4 times more likely to die than females from heroin-related causes.
- Multiple drug use common in heroin-related death
- As of 2011, opioid pain relievers are responsible for more overdose fatalities than heroin and cocaine combined.

Well-absorbed from gastrointestinal (GI) tract, nasal mucosa, pulmonary capillaries, and SC and IM injection sites
Oral dose less potent than parenteral because of 1st-pass hepatic metabolism
IV heroin peaks in <1 minute; intranasal and IM heroin peak in 3–5 minutes.
Very lipid soluble; crosses blood–brain barrier within 15–20 seconds
Extensive distribution into skeletal muscle, kidneys, liver, intestine, lungs, spleen, brain, and placenta
Rapidly crosses the placenta, entering fetal tissues within 1 hour
Crosses into breast milk in quantities sufficient to cause addiction
Excreted in urine as morphine
Receptor types
- Mu (or OP3)
  - Located in CNS, GI tract, and sensory nerve endings
  - Effect: analgesia, euphoria, respiratory depression, physical dependence, GI dysmotility, miosis, pruritus, bradycardia
  - Kappa (or OP2)
  - Located in CNS
  - Effect: analgesia, miosis, diuresis, dysphoria
  - Delta (or OP1)
  - Located in CNS
  - Effect: spinal analgesia, modulation of mu receptors/dopaminergic neurons

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