Thyroid Preparations/Bile Acid Sequestrants; Sevelamer Interactions

This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.

Medical warning:

Moderate. These medicines may cause some risk when taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.

How the interaction occurs:

If your cholesterol or phosphate binding medicine is taken at the same time as your thyroid medicine, it may also bind to the thyroid medicine in your digestive tract, preventing your body from absorbing the thyroid dose.

What might happen:

A decrease in the beneficial effects of your thyroid medicine may occur.

What you should do about this interaction:

Time your medicines so that you take your thyroid medicine four hours before or four hours after your cholesterol medicine or sevelamer.If you experience fatigue, sluggishness, constipation, stiffness, muscle cramps, loss of appetite, weight gain, dry skin, or difficulty in cold weather, contact your doctor. If you have questions about the timing of your medicines, ask your pharmacist.Your healthcare professionals (e.g. doctor or pharmacist) may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.

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  • 8.Welchol (colesevelam hydrochloride) US prescribing information. Daiichi Sankyo, Inc. October, 2021.
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  • 10.Renagel (sevelamer hydrochloride) US prescribing information. Genzyme Corporation March 9, 2016.
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  • 13.Synthroid (levothyroxine sodium) US prescribing information. Abbott Laboratories July, 2020.

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CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.