What are the primary mechanisms of illicit drug use?

Mechanisms of Illicit Drug Use

The primary mechanisms of illicit drug use include injection, inhalation, sniffing, smoking, and ingestion, each with distinct health risks and patterns of use. 1

Routes of Administration

1. Injection

• Direct introduction of substances into the bloodstream via needles and syringes
• Highest risk for bloodborne infections (HIV, hepatitis C)
• Associated with sharing of contaminated injection equipment and drug preparation supplies (water, cotton, cookers) 2
• Rapid drug delivery to the brain with maximum bioavailability 3
• Can lead to granulomatous pneumonia from drug contaminants like talcum 4

2. Inhalation/Smoking

• Second most rapid delivery method of drug to the brain 3
• Common with crack cocaine, marijuana, heroin, and methamphetamine
• Associated with respiratory complications:
  • Airway burns
  • Pneumothorax and pneumomediastinum (from increased intrathoracic pressure)
  • "Crack lung" syndrome (fever, hemoptysis, dyspnea) 4
  • Potential for obstructive lung disease with prolonged use 4
• "Shotgunning" practice (exhaling smoke into another person's mouth) increases risk of respiratory pathogen transmission 5

3. Sniffing/Snorting

• Absorption through nasal mucosa
• Common with cocaine, heroin, and prescription medications
• Can cause nasal septum perforation and chronic rhinitis
• Less rapid onset than injection or smoking but still provides significant bioavailability 3

4. Oral Ingestion

• Swallowing pills, liquids, or other drug forms
• Common with prescription drug misuse, MDMA/ecstasy, and GHB
• Slower onset but often longer duration of effect
• Associated with hyponatremia (particularly with MDMA) 6
• Risk of aspiration pneumonia with consciousness impairment 4

5. Sublingual/Buccal Administration

• Absorption through oral mucosa
• Used with certain prescription opioids and hallucinogens
• Bypasses first-pass metabolism for some substances

Pharmacokinetic Characteristics That Promote Drug Use

• Rapid absorption and delivery to the central nervous system
• High bioavailability
• Short half-life (promotes repeated use)
• Small volume of distribution
• High free drug clearance 3

Physiological Mechanisms

• Stimulants (cocaine, methamphetamine): Increase dopamine, norepinephrine levels
• Opioids (heroin, prescription opioids): Activate mu-opioid receptors
• Cannabis: Acts on cannabinoid receptors
• MDMA/Ecstasy: Increases serotonin levels 1
• Drug users adapt administration methods to optimize drug delivery to the brain while maximizing bioavailability 3

Social and Environmental Mechanisms

• Unstable living conditions
• Limited availability of sterile injection equipment
• Social marginalization and stigma
• Lack of access to substance abuse treatment programs 2, 1
• Fear of arrest by law enforcement or discrimination by healthcare providers 2

Polydrug Use Patterns

• More than 50% of people who inject drugs use multiple substances through various routes 1
• Simultaneous use of illicit drugs and legal substances (alcohol, tobacco) increases risk of drug interactions and overdose 2, 1
• Alcohol and benzodiazepine co-use significantly increases overdose risk 6

Understanding these mechanisms is crucial for developing effective prevention and treatment approaches that address the complex health and social needs of people who use drugs illicitly.