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Calcium and Vitamin D Powder and Cytomel

Determining the interaction of Calcium and Vitamin D Powder and Cytomel and the possibility of their joint administration.

Check result:
Calcium and Vitamin D Powder <> Cytomel
Relevance: 17.07.2023 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:

Using calcium carbonate together with liothyronine may decrease the effects of liothyronine. You should separate the administration of liothyronine and calcium carbonate by at least 4 hours. If your doctor does prescribe these medications together, you may need a dose adjustment or special test to safely use both medications. 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 calcium-containing products may decrease the oral bioavailability of levothyroxine by one-third in some patients. Pharmacologic effects of levothyroxine may be reduced. The exact mechanism of interaction is unknown but may involve nonspecific adsorption of levothyroxine to calcium at acidic pH levels, resulting in an insoluble complex that is poorly absorbed from the gastrointestinal tract. In one study, 20 patients with hypothyroidism who were taking a stable long-term regimen of levothyroxine demonstrated modest but significant decreases in mean free and total thyroxine (T4) levels as well as a corresponding increase in mean thyrotropin (thyroid-stimulating hormone, or TSH) level following the addition of calcium carbonate (1200 mg/day of elemental calcium) for 3 months. Four patients had serum TSH levels that were higher than the normal range. Both T4 and TSH levels returned to near-baseline 2 months after discontinuation of calcium, which further supported the likelihood of an interaction. In addition, there have been case reports suggesting decreased efficacy of levothyroxine during calcium coadministration. It is not known whether this interaction occurs with other thyroid hormone preparations.

MANAGEMENT: Some experts recommend separating the times of administration of levothyroxine and calcium-containing preparations 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
  • Singh N, Singh PN, Hershman JM "Effect of calcium carbonate on the absorption of levothyroxine." JAMA 283 (2000): 2822-5
  • Neafsey PJ "Levothyroxine and calcium interaction: timing is everything." Home Healthc Nurse 22 (2004): 338-9
  • 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
  • Schneyer CR "Calcium carbonate and reduction of levothyroxine efficacy." JAMA 279 (1998): 750
Calcium and Vitamin D Powder

Generic Name: calcium / vitamin d

Brand name: Calcitrate with D, Caltrate 600+D Soft Chews, Citracal + D, Os-Cal Extra D3, Oystercal-D, UpCal D, Os-Cal 250 with D, Oysco D, Dical-D, Calcet, Oyster Shell Calcium with Vitamin D, O-Cal-D, Oyster-D, Oyst-Cal-D, Caltro with Vitamin D, Oysco 500 with D, Oysco D with Calcium, Os-Cal with D, Caltrate 600 with D, Calcarb with D, Posture-D H/P, Dical Captabs, Dicalphos plus D, Os-Cal 500 with D, Caltrate 600 with D Plus Soy, Caltrate Colon Health, Calvite P & D, Sedecal D, Chewable Calcium with Vitamin D, Osteocit D Plus, Os-Cal 500 + D, Citracal Petites, Citracal Creamy Bites, Citracal 250 mg + D, Calcio Del Mar, Citrus Calcium with Vitamin D, Calcium 600+D, Risacal-D, Liquid Calcium with Vitamin D, Citracal Maximum + D, Citracal Calcium + D Slow Release 1200, Citracal Calcium Gummies, Caltrate Gummy Bites, Super Calcium 600 + D3 400, Os-Cal Calcium+D3, Caltrate 600 + D, Citracal Regular, Calcet Petites, Calcium 500+D, D3 with Calcium, Calcitrate, Caltrate 600+D, Os-Cal 500+D, Os-Cal 500+Extra D Chewable

Synonyms: Calcium and vitamin D combination

Cytomel

Generic Name: liothyronine

Brand name: Cytomel, Triostat

Synonyms: n.a.

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.

Interaction with food and lifestyle