Lysergic acid diethylamide (LSD) is the first synthetic hallucinogen which gained popularity in the 1960s to 1980s as a recreational drug. Its psychedelic effects usually involve heightening or distortion of sensory stimuli and enhancement of feelings and introspection. It is one of the most potent psychoactive compounds known.


  • Incidence: 5.00 cases per 100,000 person-years
  • Peak incidence: 30-40 years
  • Sex ratio: 1:1
<1 1-5 6+ 16+ 30+ 40+ 50+ 60+ 70+ 80+

Clinical features

Patients with LSD toxicity typically present following acute panic reactions (known as bad trips), massive ingestions or unintentional ingestions.

Psychoactive symptoms
  • Variable subjective experiences
  • Impaired judgements which can lead to injury
  • Amplification of current mood which leads to euphoria or dysphoria
  • Agitation, appearing withdrawn - especially in inexperienced users
  • Drug-induced psychosis

Somatic symptoms
  • Nausea
  • Headache
  • Palpitations
  • Dry mouth
  • Drowsiness
  • Tremors

  • Tachycardia
  • Hypertension
  • Mydriasis
  • Paresthesia
  • Hyperreflexia
  • Pyrexia

Manifestations such as tachycardia, hypertension, pupillary dilation, tremor, and hyperpyrexia can occur within minutes following oral administration of 0.5–2 µg/kg.

Massive overdoses can lead to the following complications:
  • Respiratory arrest
  • Coma
  • Hyperthermia
  • Autonomic dysfunction
  • Bleeding disorders


  • The diagnosis of LSD toxicity is mainly based on history and examination.
  • Most urine drug screens do not pick up LSD.


  • Management of the intoxicated patient is dependent on the specific behavioural manifestation elicited by the drug.
  • Agitation, e.g. from a 'bad trip', should be first managed with supportive reassurance in a calm, stress-free environment. If ineffective, benzodiazepines are the medication of choice.
  • LSD-induced psychosis may require antipsychotics.
  • Massive ingestions of LSD should be treated with supportive care, including respiratory support and endotracheal intubation if needed. Hypertension, tachycardia, and hyperthermia should be treated symptomatically. Hypotension should be treated initially with fluids and subsequently with vasopressors if required.
  • Because LSD is rapidly absorbed through the gastrointestinal tract, activated charcoal administration and gastric emptying are of little clinical value by the time a patient presents to the emergency department.