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Lorazepam

Class
Indications
  • Short-term management of severe anxiety
  • Short-term treatment of insomnia
  • Convulsive status epilepticus
  • Treatment and prevention of alcohol withdrawal syndrome
  • Sedation induction and anterograde amnesia
  • Impaired liver function is not a hazard with lorazepam
    • Does not require oxidation, hepatic or otherwise, for its metabolism
Administration/Absorption
  • IV
  • Oral
Dosage

Distribution
  • Readily absorbed with an absolute bioavailability of 90%
  • 85% protein bound
Mechanism
  • Binds to an allosteric site on GABA-A receptors, which are pentameric ionotropic receptors in the CNS
  • Binding potentiates the effects of the inhibitory neurotransmitter GABA
    • Opens the chloride channel in the receptor, allowing chloride influx and causing hyperpolerization of the neuron
Excretion
  • Lorazepam is rapidly conjugated at its 3-hydroxy group into lorazepam glucuronide which is then excreted in the urine
  • Half-life 12 hours
Side effects
  • Any of the five intrinsic benzodiazepine effects possessed by benzodiazepines
    • Sedative/hypnotic, muscle relaxant, anxiolytic, amnesic, and anticonvulsant
  • Paradoxical effects
  • Suicidality
  • Withdrawal effects
Interactions

Contraindications
Comments