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Olmesartan and Cholestyramine Interaction

Drug interaction information between Olmesartan and Cholestyramine.

Olmesartan and Cholestyramine have a documented moderate interaction in FDA labeling.

FDA drug labeling documents a moderate-severity interaction between Olmesartan and Cholestyramine. Major interactions are generally avoided, moderate ones may need monitoring or a dose adjustment, and minor ones are usually low-risk. This page shows the documented mechanism and guidance. Label-documented interactions are not a complete safety review, so always confirm your own medications with a pharmacist or doctor. Educational information, not medical advice.

Drug A

Olmesartan

Angiotensin II Receptor Blocker (ARB)

Drug B

Cholestyramine

Bile Acid Sequestrant

How They Interact

Cholestyramine can trap other medicines in your gut, which prevents your body from absorbing them properly. This can make your blood pressure medicine less effective.

What To Do

You should talk to your doctor about how to time your doses. They may suggest taking your blood pressure medicine at least 4 hours before the cholestyramine.

FDA Label Information

7 DRUG INTERACTIONS Lithium: Risk of lithium toxicity ( 7.2 ) Non-Steroidal Anti-Inflammatory Drugs (NSAIDs): Reduced diuretic, natriuretic and antihypotensive effects; increased risk of renal toxicity ( 7.3 ) Dual inhibition of the renin-angiotensin system: Increased risk of renal impairment, hypotension, and hyperkalemia ( 7.4 ) Colesevelam hydrochloride: Consider administering olmesartan at least 4 hours before colesevelam hydrochloride dose ( 7.5 ) Antidiabetic drugs: Dosage adjustment may be required ( 7.6 ) Cholestyramine and colestipol: Reduced absorption of thiazides ( 7.6 ) 7.1...

Frequently Asked Questions

Can I take Olmesartan and Cholestyramine together?

This is a moderate interaction. You should talk to your doctor about how to time your doses. They may suggest taking your blood pressure medicine at least 4 hours before the cholestyramine.

How serious is the interaction between Olmesartan and Cholestyramine?

This interaction is classified as "moderate" severity by the FDA. Moderate interactions may worsen your condition or change how your medications work.

Why do Olmesartan and Cholestyramine interact?

Cholestyramine can trap other medicines in your gut, which prevents your body from absorbing them properly. This can make your blood pressure medicine less effective.

Understanding the Olmesartan and Cholestyramine Interaction

FDA-approved prescribing information for these two drugs flags their combination as a moderate-severity interaction. Olmesartan belongs to the Angiotensin II Receptor Blocker (ARB) class and Cholestyramine belongs to the Bile Acid Sequestrant class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Cholestyramine can trap other medicines in your gut, which prevents your body from absorbing them properly. Severity tiers matter: major flags generally advise avoidance, moderate flags often require monitoring or dose adjustment, and minor flags may only call for awareness.

Context around a specific patient determines real-world impact. Olmesartan has 7 total documented interactions on file in this dataset, and Cholestyramine has 34. Each additional medication compounds the interaction surface, which is why pharmacists run full-profile checks rather than evaluating one pair at a time. FDA-derived guidance for this pair is: You should talk to your doctor about how to time your doses. Timing of doses, renal and hepatic function, age, and other concurrent prescriptions all shape whether a labeled interaction matters clinically.

An interaction flag is not a verdict. A large share of labeled interactions are managed routinely in clinical practice, the fix may be as simple as spacing doses or adding a monitoring test. Others require the prescriber to choose a different medication entirely. This page surfaces FDA-sourced labeling and openFDA data for educational purposes only; it is not medical advice and cannot account for your full clinical picture. Never start, stop, or adjust either Olmesartan or Cholestyramine based on a web page, speak with your prescriber or pharmacist before making any change.

Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. Always consult your healthcare provider about drug interactions.