Drug interactions
Minocycline + Phenindione
Severity: Moderate
Minocycline and Phenindione: 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
Tetracyclines such as minocycline may enhance the anticoagulant effect of vitamin K antagonists, increasing INR and bleeding risk in some patients. The effect is variable and based mostly on case reports and class data.
What this interaction means in plain words
Minocycline and Phenindione 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
Proposed reduction of vitamin K-producing gut flora and possible effects on clotting factor synthesis; mechanism is not firmly established.
What to do
Monitor INR or prothrombin time when starting or stopping minocycline and adjust phenindione dose as needed. Counsel the patient to report bleeding or bruising.
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 Minocycline
- Acitretin + Minocycline Contraindicated
- Isotretinoin + Minocycline Contraindicated
- Cholera vaccine + Minocycline Major
- Methoxyflurane + Minocycline Major
- Minocycline + Palovarotene Major
- Minocycline + Pexidartinib Major
Frequently asked questions
Can I take Minocycline with Phenindione?
MediHelp rates the interaction as moderate. Minocycline and Phenindione 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. Tetracyclines such as minocycline may enhance the anticoagulant effect of vitamin K antagonists, increasing INR and bleeding risk in some patients. The effect is variable and based mostly on case reports and class data.
How serious is the interaction between Minocycline and Phenindione?
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 or prothrombin time when starting or stopping minocycline and adjust phenindione dose as needed. Counsel the patient to report bleeding or bruising.
What other medicines interact with Minocycline?
MediHelp also lists interactions of Minocycline with, for example, Acitretin, Isotretinoin, Cholera vaccine. The full list is on the Minocycline page.
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