Drug interactions
Tolbutamide + Warfarin
Severity: Moderate
Tolbutamide and Warfarin: 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
Both drugs are CYP2C9 substrates and highly protein bound, so they may displace or compete with each other, altering INR and glucose-lowering effect. Hypoglycemia or increased anticoagulation can result.
What this interaction means in plain words
Tolbutamide and Warfarin 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.
Tolbutamide belongs to Endocrine; Warfarin belongs to Cardiovascular.
Why it happens
Competition for CYP2C9 metabolism and protein binding.
What to do
Monitor INR and blood glucose when starting, stopping or changing doses; adjust either drug as needed.
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?
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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 Tolbutamide
- Glyburide-metformin + Tolbutamide Major
- Insulin degludec-liraglutide + Tolbutamide Major
- Aceclofenac + Tolbutamide Moderate
- Acemetacin + Tolbutamide Moderate
- Acetylsalicylic acid + Tolbutamide Moderate
- Albiglutide + Tolbutamide Moderate
Frequently asked questions
Can I take Tolbutamide with Warfarin?
MediHelp rates the interaction as moderate. Tolbutamide and Warfarin 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. Both drugs are CYP2C9 substrates and highly protein bound, so they may displace or compete with each other, altering INR and glucose-lowering effect. Hypoglycemia or increased anticoagulation can result.
How serious is the interaction between Tolbutamide and Warfarin?
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 INR and blood glucose when starting, stopping or changing doses; adjust either drug as needed.
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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