Lorazepam — Drug Monograph

Brand names: Ativan

Drug class: Supportive Care Agent

Mechanism of Action

Benzodiazepine that enhances the effect of γ-aminobutyric acid (GABA) at the GABAA receptor, producing anxiolytic, sedative, amnestic, and anticonvulsant effects. Not a primary antiemetic agent — does not directly block 5-HT3, D2, or NK1 receptors. Its value in CINV is as an adjunct: anxiolysis reduces anticipatory nausea (a conditioned psychological response); amnesia blunts recall of nausea events; and sedation during chemotherapy infusion reduces distress. Often used as part of the "ABC" rescue regimen (Ativan + Benadryl + Compazine).

FDA Indications

• Management of anxiety disorders or short-term anxiety relief
• Preanesthetic medication (IV formulation)
• Status epilepticus (IV formulation)

Common Side Effects

• Sedation/drowsiness
• Dizziness
• Weakness/ataxia
• Amnesia (anterograde — often used therapeutically)
• Respiratory depression at higher doses

Clinical Pearl

Lorazepam is most valuable for anticipatory nausea — the conditioned response that begins hours or days before chemotherapy in patients who have previously experienced severe CINV. NCCN recommends lorazepam as an adjunct for anticipatory CINV management. A low dose the night before chemo (0.5 mg) reduces anticipatory anxiety significantly. The "ABC" regimen (Ativan + Benadryl + Compazine) is a time-tested rescue strategy in oncology nursing for breakthrough nausea when first-line agents fail.

Related Therapies & Mechanisms

• Aprepitant (Emend) — Supportive Care Agent
• Avatrombopag (Doptelet) — Supportive Care Agent
• Darbepoetin Alfa (Aranesp) — Supportive Care Agent
• Defibrotide (Defitelio) — Supportive Care Agent