Understanding Possible Side Effects

SYNTHROID is contraindicated in patients with uncorrected adrenal insufficiency see WARNINGS AND PRECAUTIONS. Long-term carcinogenicity studies in animals to evaluate the carcinogenic potential of levothyroxine have not been performed. Studies to evaluate mutagenic potential and animal fertility have not been performed. Concurrent use of ketamine and SYNTHROID may produce marked hypertension and tachycardia.

This is not a complete list of side effects and others may occur. We anticipate reposting the images once we are able identify and filter out images that do not match the information provided in the drug labels. Note that this list is not all-inclusive and includes only common medications that may interact with Synthroid. You should refer to the prescribing information for Synthroid for a complete list of interactions. Pregnant and lactating females need to discuss the dose and use of this medication with their caregivers. This document does not contain all possible side effects and others may occur.

How is Synthroid supplied

Thyroid hormones may increase the risk of coronary insufficiency when sympathomimetic agents are administered to patients with coronary artery disease. Pseudotumor cerebri and slipped capital femoral epiphysis have been reported in pediatric patients receiving levothyroxine therapy. SYNTHROID is indicated in adult and pediatric patients, including neonates, as an adjunct to surgery and radioiodine therapy in the management of thyrotropin-dependent well-differentiated thyroid cancer. Many other medicines can be affected by your thyroid hormone levels.

For pregnant patients with pre-existing hypothyroidism, measure serum TSH and free-T4 as soon as pregnancy is confirmed and, at minimum, during each trimester of pregnancy. In pregnant patients with primary hypothyroidism, maintain serum TSH in the trimester-specific reference range. Hypothyroidism is when the thyroid gland doesn’t make enough of the thyroid hormone called thyroxine (T4). This causes the body’s system to slow down and can lead to symptoms like fatigue, feeling cold, weight gain due to fluid retention, dry skin, and hair loss.

Drug Interactions

• Do not administer in foods that decrease absorption of SYNTHROID, such as soybean-based infant formula.
• This hormone nuclear receptor complex activates gene transcription and synthesis of messenger RNA and cytoplasmic proteins.
• Pregnant and lactating females need to discuss the dose and use of this medication with their caregivers.
• Thyroid hormones do not readily cross the placental barrier see Use in Specific Populations (8.1).

This hormone nuclear receptor complex activates gene transcription and synthesis of messenger RNA and cytoplasmic proteins. The physiological actions of thyroid hormones are produced predominantly by T3, the majority of which (approximately 80%) is derived from T4 by deiodination in peripheral tissues. Reduce the SYNTHROID dosage or discontinue temporarily if signs or symptoms of overdosage occur. Initiate appropriate supportive treatment as dictated by the patient’s medical status.

If so, advise them to stop biotin supplementation at least 2 days before assessing TSH and/or T4 levels see DOSAGE AND ADMINISTRATION and DRUG INTERACTIONS. Synthroid is also used in patients who need surgery and radioiodine therapy to manage a type of thyroid cancer called well-differentiated thyroid cancer. Synthroid is a prescription medicine used to treat hypothyroidism (low thyroid hormone). Levothyroxine is given when your thyroid does not produce enough of this hormone on its own.

• The relative bioavailability of SYNTHROID tablets, compared to an equal nominal dose of oral levothyroxine sodium solution, is approximately 93%.
• Seizures occurred in a 3-yearold child ingesting 3.6 mg of levothyroxine.
• In euthyroid patients, doses within the range of daily hormonal requirements are ineffective for weight reduction.
• Dangerous side effects or death can occur from the misuse of levothyroxine, especially if you are taking any other weight-loss medications or appetite suppressants.

2 Important Considerations for Dosing

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Consider changes in TBG concentration when interpreting T4 and T3 values. Measure and evaluate unbound (free) hormone and/or determine the free-T4 index (FT4I) in this circumstance. Pregnancy, infectious hepatitis, estrogens, estrogen-containing oral contraceptives, and acute intermittent porphyria increase TBG concentration.

PATIENT COUNSELING INFORMATION

Medicines that interact with Synthroid may either decrease its effect, affect how long it works, increase side effects, or have less of an effect when taken with Synthroid. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed. ​Biotin supplementation may interfere with immunoassays for TSH, T4, and T3, resulting in erroneous thyroid hormone test results.

Taking Synthroid the right way

TSH lower limit of quantification was 0.2 mIU/L and upper limit of normal was 5.6 mIU/L, as indicated by the shaded area. SYNTHROID is not indicated for treatment of hypothyroidism during the recovery phase of subacute thyroiditis. Administer SYNTHROID at least 4 hours before or after drugs known to interfere with SYNTHROID absorption. A portion of the conjugated hormone reaches the colon unchanged and is eliminated in the feces.

Published studies report that levothyroxine is present in human milk following the administration of oral levothyroxine. No adverse effects on the breastfed infant have been reported and there is no information on the effects of levothyroxine on milk production. Adequate levothyroxine treatment during lactation may normalize milk production in hypothyroid lactating mothers synthroid online with low milk supply. Concurrent use of sympathomimetics and SYNTHROID may increase the effects of sympathomimetics or thyroid hormone.