Methacycline and Cholestyramine Resin: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Cholestyramine Resin
Methacycline
No brand names on record
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Decreased methacycline concentrations
Interaction Deep Dive
Concomitant cholestyramine and tetracycline administration may reduce or delay tetracycline absorption. It is suggested that these agents not be given at the same time. Tetracyclines should be given at least one hour before or four to six hours after the cholestyramine resin1.
Why it happens (mechanism)
Binding of methacycline by cholestyramine resin
Common questions
Can I take Methacycline and Cholestyramine Resin together?
Decreased methacycline concentrations Always confirm with your pharmacist or prescriber before making any change.
How serious is the Methacycline and Cholestyramine Resin interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Methacycline or Cholestyramine Resin need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there anything you'd monitor while I'm on both?
References (1)
- Product Information: Questran(R), cholestyramine. Bristol Laboratories, Evansville, IN, 1997. DailyMed
Keep reading about Cholestyramine Resin
Keep reading about Methacycline
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Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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