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Drug Interactions between liothyronine and Velphoro

This report displays the potential drug interactions for the following 2 drugs:

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Interactions between your drugs

Moderate

liothyronine sucroferric oxyhydroxide

Applies to: liothyronine and Velphoro (sucroferric oxyhydroxide)

ADJUST DOSING INTERVAL: Coadministration with sucroferric oxyhydroxide may reduce the oral bioavailability of levothyroxine. The proposed mechanism involves nonspecific adsorption of levothyroxine to the ferric ion component of sucroferric oxyhydroxide, resulting in an insoluble complex that is poorly absorbed from the gastrointestinal tract. According to the product labeling for sucroferric oxyhydroxide, an in vitro interaction with levothyroxine was observed when studied in aqueous solutions that mimic the physico-chemical conditions of the gastrointestinal tract. This is consistent with previous studies that have reported a clinically significant interaction between levothyroxine and iron salts. In one study, 14 patients with hypothyroidism who were taking a stable long-term regimen of levothyroxine demonstrated an increase in mean serum thyrotropin (thyroid-stimulating hormone, or TSH) level from 1.6 to 5.4 mU/L following the addition of ferrous sulfate (300 mg administered simultaneously with levothyroxine 30 to 60 minutes before breakfast) for 3 months. A total of 11 patients had increases in serum TSH at week 12 compared to baseline, including two that had levels above the upper limit of normal for the assay, indicating the presence of hypothyroidism. Nine of the eleven also had an increase in signs and symptoms of hypothyroidism based on subjective evaluation using a clinical score. It is not known whether this interaction occurs with other thyroid hormone preparations.

MANAGEMENT: Oral formulations of levothyroxine should be administered at least 4 hours before sucroferric oxyhydroxide.

References (4)
  1. Campbell NR, Hasinoff BB, Stalts H, Rao B, Wong NC (1992) "Ferrous sulfate reduces thyroxine efficacy in patients with hypothyroidism." Ann Intern Med, 117, p. 1010-3
  2. (2024) "Product Information. Velphoro (sucroferric oxyhydroxide)." Fresenius Medical Care North America
  3. (2024) "Product Information. Velphoro (sucroferric oxyhydroxide)." Vifor Fresenius Medical Care Renal Pharma Ltd.
  4. (2024) "Product Information. Velphoro (sucroferric oxyhydroxide)." Fresenius Kabi Australia Pty Limited

Drug and food interactions

Moderate

liothyronine food

Applies to: liothyronine

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 (4)
  1. Schneyer CR (1998) "Calcium carbonate and reduction of levothyroxine efficacy." JAMA, 279, p. 750
  2. Singh N, Singh PN, Hershman JM (2000) "Effect of calcium carbonate on the absorption of levothyroxine." JAMA, 283, p. 2822-5
  3. Csako G, McGriff NJ, Rotman-Pikielny P, Sarlis NJ, Pucino F (2001) "Exaggerated levothyroxine malabsorption due to calcium carbonate supplementation in gastrointestinal disorders." Ann Pharmacother, 35, p. 1578-83
  4. Neafsey PJ (2004) "Levothyroxine and calcium interaction: timing is everything." Home Healthc Nurse, 22, p. 338-9

Therapeutic duplication warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.

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Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

Further information

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