10.3 Substance Abuse & Addiction
Understanding drugs of abuse, their mechanisms, withdrawal syndromes, and pharmacological treatments for addiction is crucial for managing substance use disorders.
Opioid Use Disorder
Treatment Options
Methadone
- • Full μ-opioid agonist
- • Long half-life (prevents withdrawal)
- • Daily supervised dosing (clinic)
- • QT prolongation risk
Buprenorphine
- • Partial μ-agonist (ceiling effect)
- • With naloxone (Suboxone) to prevent abuse
- • Office-based treatment
- • Safer overdose profile
Naltrexone
- • μ-opioid antagonist
- • Blocks effects of opioids
- • Monthly IM injection (Vivitrol)
- • Must be opioid-free before starting
Alcohol Use Disorder
Disulfiram
- • Inhibits aldehyde dehydrogenase
- • Causes acetaldehyde accumulation if alcohol consumed
- • Severe flushing, nausea, hypotension
- • Requires patient motivation
Naltrexone & Acamprosate
- • Naltrexone: Blocks endorphin reward pathway
- • Acamprosate: Modulates NMDA/GABA (↓ craving)
- • Both reduce relapse rates
Stimulants & Cannabis
Stimulants (Cocaine, Amphetamines)
- • ↑ Dopamine, norepinephrine, serotonin
- • Acute: HTN, tachycardia, hyperthermia, psychosis
- • Withdrawal: Depression, fatigue, anhedonia
- • No specific pharmacotherapy (supportive care)
Cannabis (THC)
- • CB1/CB2 receptor agonist
- • Effects: Euphoria, relaxation, ↑ appetite, impaired cognition
- • Withdrawal: Irritability, insomnia, decreased appetite
- • No specific pharmacotherapy