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Cytomel and Magnesium hydroxide

Determining the interaction of Cytomel and Magnesium hydroxide and the possibility of their joint administration.

Check result:

Cytomel <> Magnesium hydroxide

Relevance: 04.11.2023 Reviewer: Shkutko P.M., M.D., in

In the database of official manuals used in the service creation an interaction registered by statistical results of studies was found, which can either lead to negative consequences for the patient health or strengthen a mutual positive effect. A doctor should be consulted to address the issue of joint drug administration.

Consumer:

Taking the liothyronine and magnesium hydroxide doses too close together may interfere with the absorption of liothyronine and reduce its effectiveness. To prevent or minimize the interaction, these medications should preferably be taken at least four hours apart. Contact your doctor if you experience signs and symptoms of reduced thyroid function such as fatigue; sluggishness; constipation; depression; hoarseness; unexplained weight gain; sensitivity to cold; pale, dry skin; muscle aches, weakness, or tenderness; joint pain, stiffness, or swelling; heavier than normal menstruation periods; or brittle fingernails and hair. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Professional:

ADJUST DOSING INTERVAL: Concurrent administration of simethicone and/or antacid preparations may decrease the oral bioavailability of levothyroxine. Pharmacologic effects of levothyroxine may be reduced. The exact mechanism of interaction is unknown but may involve nonspecific adsorption of levothyroxine to polyvalent cations, resulting in an insoluble complex that is poorly absorbed from the gastrointestinal tract. There have been case reports suggesting decreased efficacy of levothyroxine during coadministration of aluminum- and magnesium-containing antacids, as well as other products containing polyvalent cations such as calcium and iron. In one report, a man stabilized on levothyroxine 150 mcg/day developed significantly increased serum thyrotropin (thyroid-stimulating hormone, or TSH) levels while taking an aluminum and magnesium hydroxide antacid. The apparent interaction was also observed on two subsequent rechallenges. Other case reports have described increased dosage requirements of levothyroxine during antacid use. It is not known whether this interaction occurs with other thyroid hormone preparations.

MANAGEMENT: It is recommended to separate the times of administration of levothyroxine and simethicone and antacids or other antacid-containing preparations (e.g., didanosine buffered tablets or pediatric oral solution) by at least 4 hours. Monitoring of serum TSH levels is recommended. Patients with gastrointestinal or malabsorption disorders may be at a greater risk of developing clinical or subclinical hypothyroidism due to this interaction.

References

"Product Information. Synthroid (levothyroxine)." Abbott Pharmaceutical, Abbott Park, IL.
Neafsey PJ "Levothyroxine and calcium interaction: timing is everything." Home Healthc Nurse 22 (2004): 338-9
Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
Campbell NR, Hasinoff BB, Stalts H, Rao B, Wong NC "Ferrous sulfate reduces thyroxine efficacy in patients with hypothyroidism." Ann Intern Med 117 (1992): 1010-3
Cerner Multum, Inc. "Australian Product Information." O 0
Csako G, McGriff NJ, Rotman-Pikielny P, Sarlis NJ, Pucino F "Exaggerated levothyroxine malabsorption due to calcium carbonate supplementation in gastrointestinal disorders." Ann Pharmacother 35 (2001): 1578-83
Liel Y, Sperber AD, Shany S "Nonspecific intestinal adsorption of levothyroxine by aluminum hydroxide." Am J Med 97 (1994): 363-5
Schneyer CR "Calcium carbonate and reduction of levothyroxine efficacy." JAMA 279 (1998): 750
Singh N, Singh PN, Hershman JM "Effect of calcium carbonate on the absorption of levothyroxine." JAMA 283 (2000): 2822-5
Canadian Pharmacists Association "e-CPS. Available from: URL: http://www.pharmacists.ca/function/Subscriptions/ecps.cfm?link=eCPS_quikLink."
Sperber AD, Liel Y "Evidence for interference with the intestinal absorption of levothyroxine sodium by aluminum hydroxide." Arch Intern Med 152 (1992): 183-4

Cytomel

Generic Name: liothyronine

Brand name: Cytomel, Triostat

Synonyms: n.a.

What is Cytomel?

Magnesium hydroxide

Generic Name: magnesium hydroxide

Brand name: Ex-Lax Milk of Magnesia, Milk of Magnesia, Pedia-Lax Chewable, Phillips Milk of Magnesia, Concentrated Phillips Milk of Magnesia, Dulcolax Milk of Magnesia

Synonyms: Magnesium Hydroxide

What is Magnesium hydroxide?

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In the course of checking the drug compatibility and interactions, data from the following reference sources was used: Drugs.com, Rxlist.com, Webmd.com, Medscape.com.

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