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