Home›Levothyroxine›Levothyroxine + Colesevelam Hydrochloride

Does Levothyroxine Interact with Colesevelam Hydrochloride?

CDI records a major classification for Levothyroxine and Colesevelam Hydrochloride. The stored summary is: In vivo studies showed decreased levothyroxine exposure. Postmarketing reports of elevated TSH in patients on thyroid hormone replacement therapy. The mechanism involves decreased drug absorption/exposure. Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This record was extracted from drug labeling through openFDA. NIH/NLM RxNorm is used for drug identities. The summary and severity classification are CDI's processed information, not a verbatim source quotation. Product, route, and patient circumstances matter.

Severity
Major
Management
Close medical supervision required
Data Source
U.S. FDA via OpenFDA

Recorded Mechanism

Decreased drug absorption/exposure

What To Tell Your Doctor or Pharmacist

If you are taking Levothyroxine and your doctor is considering prescribing Colesevelam Hydrochloride (or vice versa), make sure to:

  • Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
  • Ask whether the benefits of combining these medications outweigh the risks for your specific situation
  • Ask what symptoms to watch for that would indicate the interaction is causing problems
  • Ask how frequently you should be monitored while these are co-prescribed
  • Ask whether any dosage adjustments are needed
  • Never stop or change either medication without first consulting your healthcare provider
💊 Levothyroxine(Thyro-Tabs)+💊 Colesevelam Hydrochloride(Welchol)

Severity & Interaction Details

⚠️
major
Use with caution — major interaction
Serious risk of clinically significant harm. Generally avoid; if used, monitor closely.
Severity scale
MinorContra
On record
Yes
Drug A class
—
Drug B class
—
Source
NLP:colesevelam hydrochloride

What this means in plain English

In vivo studies showed decreased levothyroxine exposure. Postmarketing reports of elevated TSH in patients on thyroid hormone replacement therapy.

About Levothyroxine and Colesevelam Hydrochloride

You may recognize them by the brand names Thyro-Tabs and Welchol.

Source and Limitations

This record was produced by automated extraction from drug-label information, including AI processing. The summary and mechanism are not verbatim FDA quotations. The drug profiles below may describe different formulations from the source label. Confirm the exact product and route with your pharmacist. This page does not establish independent clinical review.

📖 Source: NLP:colesevelam hydrochloride

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How this information is prepared: CDI uses automated extraction, including AI, to summarize drug labeling from openFDA and includes separately identified curated-reference records. RxNorm helps identify medications; it does not verify interaction claims. Extracted summaries and CDI severity classifications can contain errors and are not verbatim FDA statements or independent clinical review. Maintained by CheckDrugInteractions.com. See our methodology or report a correction at support@checkdruginteractions.com.

Data sourced from U.S. FDA drug labeling via openFDA and the NIH National Library of Medicine, supplemented with a small number of well-established interactions from curated clinical references. For informational purposes only. Always consult your pharmacist or physician.

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