Drug Interaction Report

Propranolol and Colestipol: Interaction Details

A pharmacist-reviewed analysis of the Propranolol and Colestipol 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

Colestipol

Colestid Colestid® Colestid® Flavored Granules Colestid® Granules
+

Propranolol

Hemangeol Inderal InnoPran
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
Moderate
Can be significant — usually manageable with monitoring.
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 76 documented Propranolol interactions, 65 are rated moderate — including this one.
Onset
delayed
Evidence
theoretical
Severity
Moderate

What happens

Decreased propranolol effectiveness

Interaction Deep Dive

Coadministration of colestipol and propranolol may decrease propranolol absorption, delay Tmax1, and decrease propranolol concentrations by up to 50% 2. Administer propranolol at least 1 hour before or 4 hours after colestipol to avoid altered absorption. Additionally, monitor when colestipol tablets are initiated or discontinued from a propranolol regimen 1.

Why it happens (mechanism)

Decreased propranolol absorption

Literature reports

1 report — tap to read

a) Repeated doses of colestipol given prior to a single dose of propranolol in trials have been reported to decrease propranolol absorption. However, in a follow-up study in normal subjects, single-dose administration of colestipol and propranolol and twice-a-day administration for 5 days of both agents did not affect the extent of propranolol absorption, but the time to reach maximum concentration was delayed approximately 30 minutes 1.

Common questions

Can I take Propranolol and Colestipol together?

Decreased propranolol effectiveness Always confirm with your pharmacist or prescriber before making any change.

How serious is the Propranolol and Colestipol interaction?

It is rated moderate. Can be significant — usually manageable with monitoring.

How quickly could this interaction happen?

The documented onset is "delayed". Effects tend to build up gradually over days to weeks.

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 Propranolol or Colestipol 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: Colestid(R) oral tablets, colestipol HCl oral tablets. Pharmacia & Upjohn Company (per FDA), New York, NY, 2014. DailyMed
  2. Product Information: Propranolol HCl oral tablets, propranolol HCl oral tablets. Amneal Pharmaceuticals LLC (per DailyMed), Bridgewater, NJ, 2019. DailyMed
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Colestipol

Keep reading about Colestipol

All Colestipol interactions (50) Colestipol drug information
Also serious with: Bezafibrate Chenodiol Deferasirox Digoxin
Propranolol

Keep reading about Propranolol

All Propranolol interactions (76) Propranolol drug information
Also serious with: Mefloquine Lacosamide Injection Capmatinib Indacaterol Oral Inhalation
Beyond drug–drug

These medications also interact with supplements

Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:

Colestipol + Activated Charcoal Coffee Charcoal European Mandrake Glucomannan Guar Gum Gum Arabic Niacin Slippery Elm + 10 more
Propranolol + Activated Charcoal American Hellebore American Mistletoe Indian Snakeroot Tyramine 1,3-dmaa Acacia Rigidula Active Hexose Correlated Compound (ahcc) + 228 more

major · moderate · minor — check everything you take with our drug–supplement interaction checker.

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.