Drug interactions
Amobarbital + Warfarin
Severity: Major
Amobarbital and Warfarin: 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 and accelerate warfarin metabolism, lowering INR and reducing anticoagulant protection. The effect develops over weeks and persists after the barbiturate is stopped, with risk of rebound overanticoagulation.
What this interaction means in plain words
Amobarbital and Warfarin 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.
Amobarbital belongs to Central Nervous System; Warfarin belongs to Cardiovascular.
Why it happens
Induction of hepatic CYP enzymes (including CYP2C9 and CYP3A4) increasing warfarin clearance.
What to do
Monitor INR frequently and increase the warfarin dose as required. Reduce the dose and recheck INR when the barbiturate is discontinued.
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 Warfarin
- Defibrotide + Warfarin Contraindicated
- Ketorolac + Warfarin Contraindicated
- Abciximab + Warfarin Major
- Acetylsalicylic acid + Warfarin Major
- Adagrasib + Warfarin Major
- Amiodarone + Warfarin Major
Other interactions of Amobarbital
- Amobarbital + Calcium / magnesium / potassium / sodium oxybates Contraindicated
- Amobarbital + Doravirine Contraindicated
- Amobarbital + Elbasvir / grazoprevir Contraindicated
- Amobarbital + Isavuconazonium Contraindicated
- Amobarbital + Isocarboxazid Contraindicated
- Amobarbital + Lonafarnib Contraindicated
Frequently asked questions
Can I take Amobarbital with Warfarin?
MediHelp rates the interaction as major. Amobarbital and Warfarin 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 and accelerate warfarin metabolism, lowering INR and reducing anticoagulant protection. The effect develops over weeks and persists after the barbiturate is stopped, with risk of rebound overanticoagulation.
How serious is the interaction between Amobarbital and Warfarin?
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 frequently and increase the warfarin dose as required. Reduce the dose and recheck INR when the barbiturate is discontinued.
What other medicines interact with Warfarin?
MediHelp also lists interactions of Warfarin with, for example, Defibrotide, Ketorolac, Abciximab. The full list is on the Warfarin page.
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