Nonopioid Drugs of Abuse

Hallucinogens (psychomimetics) – LSD, psilocybin, psilocin, dimethyltriptamine (serotonin-related)

• Common effects: Mydriasis, tachycardia, increased BP, hyperreflexia, tachypnea, increased muscle tone. Predominance of sympathomimetic effects. Perceptual distortions from simple to complex hallucinations. Magical and paranoid thinking.

• LSD – Tolerance develops. No withdrawal symptoms. Cross-tolerance with other psychokinetic. Flashbacks and bad trips treated with reassurance or diazepam. Proposed MOA is that LSD activates auto receptors on raphe neurons, resulting in depression of firing of the raphe cells, and decreased release of 5-HT from terminals (raphe acts as mental filter).

• PCP – Dissociative anesthetic that has hallucinogenic effects. Related to ketamine,

• Acute intoxication: Confusional state including unpredictable and violent behavior. Blank-stare appearance. Behavior may change to combativeness. Gross ataxia, rigidity, nystagmus, repetitive movements, and seizures. Strong analgesic effect (could be shot and wouldn’t know it).

• Toxic psychosis: Much like schizophrenia. More common than with other hallucinogens. Psychosis may persist for weeks or months and is difficult to treat (PCP and metabolites persist in body fat).

• Treatment: Reassurance and isolation to reduce external stimuli. Haloperidol for seizures. Diazepam for anxiety.

Marijuana

• Signs and symptoms of acute use: Tachycardia, conjunctival reddening.

• Chronic use: Chronic users show less psychomotor impairment and less anxiety with same dose. Reverse tolerance has not been substantiated.

• Dependence: Withdrawal is mild. Tissue stores decrease slowly. Strong psychological dependence in some people.

• Approved use: Dronabinol is approved for prevention of nausea and vomiting associated with cancer chemotherapy and as an appetite-stimulant in AIDS-related anorexia. Not effective in cisplastin therapy.

• Adverse effects: Chronic heavy use may lead to possible endocrine and immunologic disturbances, chronic bronchitis and asthma (squamous cell metaplasia), reduced exercise tolerance in patients with CAD.

Deliriants – Antimuscarinics. Bad trip man.

Inhalants – Solvents (liver, heart, and kidney problems; aplastic anemia with benzene), propellants (fluoroalkanes may precipitate arrhythmias and v-fib), nitrites (occasional methemoglobinemia).

Category: Pharmacology Notes