Toxidromes - hallucinogenic

Description

Perceptual distortion + hallucinations (usually visual) + altered sense of time/self
- Mild sympathomimetic overlay: tachycardia, mydriasis, HTN
Insight often retained (patient knows it is drug-induced) - key discriminator from anticholinergic or psychotic delirium
Two classes
- Classic serotonergic (5-HT2A agonists) - LSD, psilocybin, mescaline, NBOMe series
- Dissociatives (NMDA antagonists) - ketamine, PCP, high-dose dextromethorphan

Recreational use, festival/party settings, young adults
NBOMe series - sold as "LSD" on blotter paper, far more potent and dangerous than LSD itself

Serotonergic: 5-HT2A receptor agonism in prefrontal cortex -> altered sensory processing
Dissociative: NMDA receptor antagonism -> dissociation, analgesia, nystagmus
- PCP also dopaminergic -> agitation/violence at high dose

Clinical - mydriasis, mild tachycardia/HTN, hyperreflexia, usually normal temperature
PCP/ketamine: nystagmus (vertical, horizontal, or rotatory - distinctive), dissociation, +/- violent agitation, +/- catatonia at high dose
Exclude serotonin syndrome (clonus, hyperthermia, rigidity) if co-ingestant (esp. MDMA, SSRIs)
Urine drug screen unreliable for LSD; extended panels may detect PCP/ketamine

"Talk down" - calm, low-stimulus environment, reassurance - first line for uncomplicated intoxication
Benzodiazepines for agitation/anxiety unresponsive to reassurance
Avoid antipsychotics in PCP intoxication - dec seizure threshold, worsen dystonia, mask agitation without treating it safely
Active cooling for hyperthermia
Dark, quiet room for ketamine/PCP; monitor for laryngospasm and hypersalivation with ketamine

"Bad trip" -> panic, self-harm risk
HPPD (hallucinogen persisting perception disorder) - flashbacks after LSD, can persist months-years
Rhabdomyolysis with prolonged agitation

LSD effects 8-12h; psilocybin 4-6h; ketamine short (30-60 min)
Most resolve fully and rapidly with supportive care
Rare persisting psychosis in predisposed individuals (esp. cannabis/amphetamine co-use, family history)

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