Drug interactions
Chlorpromazine + Lorazepam
Severity: Moderate
Chlorpromazine and Lorazepam: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Chlorpromazine is strongly sedating and hypotensive, and with lorazepam it can cause marked sedation, hypotension and respiratory depression. The risk is greater in elderly patients and at higher doses.
What this interaction means in plain words
Chlorpromazine and Lorazepam can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Chlorpromazine belongs to Central Nervous System; Lorazepam belongs to Central Nervous System.
Why it happens
Additive CNS depression through GABA-A potentiation and dopamine, histamine and alpha-adrenergic blockade.
What to do
Monitor sedation, blood pressure and respiration, particularly with parenteral use. Reduce the doses in frail or elderly patients.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Chlorpromazine and Lorazepam, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Lorazepam
Other interactions of Chlorpromazine
- Chlorpromazine + Dofetilide Contraindicated
- Chlorpromazine + Dronedarone Contraindicated
- Chlorpromazine + Droperidol Contraindicated
- Chlorpromazine + Ibutilide Contraindicated
- Chlorpromazine + Metrizamide Contraindicated
- Chlorpromazine + Panobinostat Contraindicated
Frequently asked questions
Can I take Chlorpromazine with Lorazepam?
MediHelp rates the interaction as moderate. Chlorpromazine and Lorazepam can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Chlorpromazine is strongly sedating and hypotensive, and with lorazepam it can cause marked sedation, hypotension and respiratory depression. The risk is greater in elderly patients and at higher doses.
How serious is the interaction between Chlorpromazine and Lorazepam?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor sedation, blood pressure and respiration, particularly with parenteral use. Reduce the doses in frail or elderly patients.
What other medicines interact with Lorazepam?
MediHelp also lists interactions of Lorazepam with, for example, Alfentanil, Alprazolam, Amobarbital. The full list is on the Lorazepam page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
