Drug interactions
Labetalol + Phenobarbital
Severity: Moderate
Labetalol and Phenobarbital: 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
Phenobarbital may reduce plasma labetalol concentrations and weaken its blood pressure lowering effect. The effect emerges gradually with continued phenobarbital use and persists after discontinuation. Therapeutic response should be followed.
What this interaction means in plain words
Labetalol and Phenobarbital 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.
Why it happens
Phenobarbital induces hepatic enzymes, increasing the metabolic clearance of labetalol.
What to do
Monitor blood pressure and heart rate and titrate labetalol upward if needed. Lower the dose again if phenobarbital is withdrawn.
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 Labetalol and Phenobarbital, 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 14 days on the web. No card needed.
Other interactions of Labetalol
- Amifostine + Labetalol Major
- Amiodarone + Labetalol Major
- Atenolol-chlorthalidone + Labetalol Major
- Atenolol + Labetalol Major
- Betaxolol + Labetalol Major
- Bisoprolol + Labetalol Major
Frequently asked questions
Can I take Labetalol with Phenobarbital?
MediHelp rates the interaction as moderate. Labetalol and Phenobarbital 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. Phenobarbital may reduce plasma labetalol concentrations and weaken its blood pressure lowering effect. The effect emerges gradually with continued phenobarbital use and persists after discontinuation. Therapeutic response should be followed.
How serious is the interaction between Labetalol and Phenobarbital?
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 blood pressure and heart rate and titrate labetalol upward if needed. Lower the dose again if phenobarbital is withdrawn.
What other medicines interact with Labetalol?
MediHelp also lists interactions of Labetalol with, for example, Amifostine, Amiodarone, Atenolol-chlorthalidone. The full list is on the Labetalol 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.
