Drug Interaction Report

Cholestyramine Resin and L-Methylfolate: Interaction Details

A pharmacist-reviewed analysis of the Cholestyramine Resin and L-Methylfolate interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Cholestyramine Resin

Locholest® Locholest® Light Prevalite Prevalite® Questran Questran® Questran® Light
+

L-Methylfolate

No brand names on record
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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Interaction severity
Minor
Usually limited clinical impact.
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.

Of 70 documented Cholestyramine Resin interactions, 14 are rated minor — including this one.
Onset
unspecified
Evidence
theoretical
Severity
Minor

What happens

Decreased l-methylfolate serum levels

Interaction Deep Dive

L-methylfolate is the bioactive form of folic acid and is used as a medical food. Although no studies have been conducted, coadministration of cholestyramine with l-methylfolate may decrease folate absorption, thereby reducing the amount of active folate available12.

Why it happens (mechanism)

Decreased folate absorption

Common questions

Can I take Cholestyramine Resin and L-Methylfolate together?

Decreased l-methylfolate serum levels Always confirm with your pharmacist or prescriber before making any change.

How serious is the Cholestyramine Resin and L-Methylfolate interaction?

It is rated minor. Usually limited clinical impact.

How quickly could this interaction happen?

The documented onset is "unspecified". The timing of this interaction is not well characterized.

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 Cholestyramine Resin or L-Methylfolate 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 (2)

  1. Product Information: DEPLIN(R) oral tablets, l-methylfolate oral tablets. Pamlab,LLC, Covington, LA, 2006. DailyMed
  2. Product Information: Zervalx(R) oral tablets, l-methylfolate oral tablets. Pamlab,LLC, Covington, LA, 2008. DailyMed
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Cholestyramine Resin

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L-Methylfolate

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