Drug Interactions between levothyroxine / liothyronine and PediaCare Infants' Gas Relief Drops
This report displays the potential drug interactions for the following 2 drugs:
- levothyroxine/liothyronine
- PediaCare Infants' Gas Relief Drops (simethicone)
Interactions between your drugs
liotrix simethicone
Applies to: levothyroxine / liothyronine and PediaCare Infants' Gas Relief Drops (simethicone)
ADJUST DOSING INTERVAL: Concurrent administration of simethicone, sucralfate 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. Additionally, agents that affect intragastric pH may reduce levothyroxine absorption. 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 thyroid replacement hormones and simethicone, sucralfate, 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
- Sperber AD, Liel Y (1992) "Evidence for interference with the intestinal absorption of levothyroxine sodium by aluminum hydroxide." Arch Intern Med, 152, p. 183-4
- Havrankova J, Lahaie R (1992) "Levothyroxine binding by sucralfate." Ann Intern Med, 117, p. 445-6
- Khan F, Jeanniton E, Renedo M (1993) "Does sucralfate impede levothyroxine therapy?" Ann Intern Med, 118, p. 317
- (2002) "Product Information. Synthroid (levothyroxine)." Abbott Pharmaceutical
- 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
- Liel Y, Sperber AD, Shany S (1994) "Nonspecific intestinal adsorption of levothyroxine by aluminum hydroxide." Am J Med, 97, p. 363-5
- Schneyer CR (1998) "Calcium carbonate and reduction of levothyroxine efficacy." JAMA, 279, p. 750
- Singh N, Singh PN, Hershman JM (2000) "Effect of calcium carbonate on the absorption of levothyroxine." JAMA, 283, p. 2822-5
- 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
- Neafsey PJ (2004) "Levothyroxine and calcium interaction: timing is everything." Home Healthc Nurse, 22, p. 338-9
- (2024) "Product Information. Liothyronine Sodium (liothyronine)." AvKare Inc
Drug and food interactions
liotrix food
Applies to: levothyroxine / liothyronine
ADJUST DOSING INTERVAL: Consumption of certain foods as well as the timing of meals relative to dosing may affect the oral absorption of T4 thyroid hormone (i.e., levothyroxine). T4 oral absorption is increased by fasting and decreased by foods such as soybean flour (e.g., infant formula), cotton seed meal, walnuts, dietary fiber, calcium, and calcium fortified juices. Grapefruit or grapefruit products may delay the absorption of T4 thyroid hormone and reduce its bioavailability. The mechanism of this interaction is not fully understood.
MANAGEMENT: Some manufacturers recommend administering oral T4 as a single daily dose, on an empty stomach, one-half to one hour before breakfast. In general, oral preparations containing T4 thyroid hormone should be administered on a consistent schedule with regard to time of day and relation to meals to avoid large fluctuations in serum levels. Foods that may affect T4 absorption should be avoided within several hours of dosing if possible. Consult local guidelines for the administration of T4 in patients receiving enteral feeding.
References
- (2002) "Product Information. Synthroid (levothyroxine)." Abbott Pharmaceutical
- (2022) "Product Information. Armour Thyroid (thyroid desiccated)." Forest Pharmaceuticals
- Wohlt PD, Zheng L, Gunderson S, Balzar SA, Johnson BD, Fish JT (2009) "Recommendations for the use of medications with continuous enteral nutrition." Am J Health Syst Pharm, 66, p. 1438-67
liotrix food
Applies to: levothyroxine / 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
- Schneyer CR (1998) "Calcium carbonate and reduction of levothyroxine efficacy." JAMA, 279, p. 750
- Singh N, Singh PN, Hershman JM (2000) "Effect of calcium carbonate on the absorption of levothyroxine." JAMA, 283, p. 2822-5
- 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
- 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.
See also
Drug Interaction Classification
Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit. | |
Moderately clinically significant. Usually avoid combinations; use it only under special circumstances. | |
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. | |
No interaction information available. |
Further information
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