Drug interactions
Phenindione + Secobarbital
Severity: Major
Phenindione and Secobarbital: major 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
Barbiturates induce hepatic enzymes that metabolize oral anticoagulants, which can reduce the anticoagulant effect of phenindione. Stopping the barbiturate later can cause the effect to rebound and raise bleeding risk.
What this interaction means in plain words
Phenindione and Secobarbital can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
Hepatic enzyme induction by secobarbital increases the metabolism of phenindione.
What to do
Monitor INR closely and adjust the phenindione dose when starting or stopping secobarbital. Use a non-inducing hypnotic where possible.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Secobarbital
- Calcium / magnesium / potassium / sodium oxybates + Secobarbital Contraindicated
- Doravirine + Secobarbital Contraindicated
- Elbasvir / grazoprevir + Secobarbital Contraindicated
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Secobarbital Contraindicated
- Isavuconazonium + Secobarbital Contraindicated
- Lonafarnib + Secobarbital Contraindicated
Frequently asked questions
Can I take Phenindione with Secobarbital?
MediHelp rates the interaction as major. Phenindione and Secobarbital can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Barbiturates induce hepatic enzymes that metabolize oral anticoagulants, which can reduce the anticoagulant effect of phenindione. Stopping the barbiturate later can cause the effect to rebound and raise bleeding risk.
How serious is the interaction between Phenindione and Secobarbital?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor INR closely and adjust the phenindione dose when starting or stopping secobarbital. Use a non-inducing hypnotic where possible.
What other medicines interact with Secobarbital?
MediHelp also lists interactions of Secobarbital with, for example, Calcium / magnesium / potassium / sodium oxybates, Doravirine, Elbasvir / grazoprevir. The full list is on the Secobarbital page.
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