Drugs Abuse

Question 1

Opioids (e.g., heroin, morphine, oxycodone)

Answer 1

Mechanism: Mu receptor agonists → CNS and respiratory depression

Intoxication:
• Miosis (pinpoint pupils)
• Respiratory depression, bradycardia
• Decreased bowel sounds

Withdrawal:
• Yawning, dilated pupils, piloerection (“cold turkey”), lacrimation, rhinorrhea, diarrhea, myalgia

Treatment:
• Naloxone for overdose
• Methadone or buprenorphine for maintenance

Tip: Pinpoint pupils + respiratory depression = opioid overdose. Know naloxone is short-acting.

Question 2

Cocaine

Answer 2

Mechanism: Inhibits reuptake of NE, dopamine, serotonin

Intoxication:
• Mydriasis, agitation, tachycardia, hypertension, hallucinations, chest pain
• Risk of MI, stroke, arrhythmia

Withdrawal: Depression, hypersomnia, craving

Tip: Chest pain in a young person + ST elevation = cocaine-induced MI. Benzodiazepines are used for agitation; beta-blockers are contraindicated (unopposed α effect).

Question 3

Amphetamines (e.g., methamphetamine)

Answer 3

Mechanism: ↑ release of NE and dopamine
• Intoxication:
• Euphoria, mydriasis, agitation, arrhythmias, seizures
• Paranoid psychosis (can mimic schizophrenia)

Tip: Look for dental decay (“meth mouth”), weight loss, and skin picking.

Question 4

Benzodiazepines

Answer 4

Mechanism: ↑ GABA-A activity (↑ frequency of Cl⁻ channel opening)
• Intoxication: Sedation, ataxia, mild respiratory depression

Withdrawal: Tremors, anxiety, seizures

Treatment:
• Flumazenil (rarely used due to risk of seizures)

Tip: Benzo withdrawal can mimic alcohol withdrawal but is usually less severe unless long-term/high dose.

Question 5

Barbiturates

Answer 5

Mechanism: ↑ GABA-A activity (↑ duration of Cl⁻ channel opening)
• Intoxication: Respiratory and CNS depression
• Withdrawal: Anxiety, seizures, delirium (can be life-threatening)

Tip: Barbiturate overdose can be fatal and has no antidote. Supportive care only.

Question 6

Alcohol

Answer 6

Intoxication: Disinhibition, slurred speech, ataxia, hypoglycemia
• Withdrawal:
• 6–12h: Tremors, insomnia, GI upset
• 12–48h: Seizures, hallucinations
• 48–96h: Delirium tremens—confusion, fever, autonomic instability

Treatment:
• Benzodiazepines (e.g., lorazepam, diazepam)

Tip: Know the timeline of alcohol withdrawal and that DTs are fatal if untreated.

Question 7

Nicotine

Answer 7

Mechanism: Nicotinic ACh receptor agonist → stimulates dopamine release
• Withdrawal: Irritability, anxiety, increased appetite, weight gain
• Treatment: Nicotine replacement, bupropion, varenicline

Tip: Varenicline is a partial agonist at nicotinic receptors.

Question 8

Marijuana (THC)

Answer 8

Intoxication: Euphoria, conjunctival injection, slowed time perception, ↑ appetite
• Withdrawal: Irritability, insomnia, decreased appetite

Tip: Chronic use affects short-term memory and motivation (amotivational syndrome).

Question 9

Hallucinogens

Answer 9

a) LSD (acid)
• Intoxication: Visual hallucinations, synesthesia, anxiety or psychosis, mydriasis

b) PCP
• NMDA antagonist
• Violent behavior, psychosis, nystagmus, muscle rigidity

Tip: PCP = nystagmus + aggression + hallucinations.

Question 10

Inhalants (glue, toluene)

Answer 10

CNS depression, euphoria
• Rash around mouth, sudden sniffing death (arrhythmia)

Tip: Look for a teen with chemical smell + perioral rash + sudden cardiac arrest.