Thyroid Hormone Replacement Therapy

If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines. 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.

Levothyroxine is given when your thyroid does not produce enough of this hormone on its own. Synthroid (levothyroxine) treats hypothyroidism (low thyroid hormone) and different types of … Make sure any doctor or dentist who treats you knows that you or your child are using this medicine. You or your child may need to stop using this medicine several days before having surgery or medical tests.

Side Effects for Synthroid

Serum digitalis glycoside levels may decrease when a hypothyroid patient becomes euthyroid, necessitating an increase in the dose of digitalis glycosides. Many drugs can inhibit Synthroid’s adsorption by the body; other medications may increase or decrease its effectiveness once it is adsorbed. Providing a complete list of medications to the doctor will help with getting the correct dose established for each individual patient. If you become pregnant while taking Synthroid, do not stop taking the medicine without your doctor’s advice. Having low thyroid hormone levels during pregnancy could harm both mother and baby.

Other Interactions

Pediatric dosage should follow the recommendations summarized in Table 1. In infants with congenital hypothyroidism, therapy with full doses should be instituted as soon as the diagnosis has been made. Serum TSH levels should be monitored and the SYNTHROID dosage adjusted during pregnancy. Since postpartum TSH levels are similar to preconception values, the SYNTHROID dosage should return to the pre-pregnancy dose immediately after delivery see Dosage and Administration (2.3).

Do not share this medicine with another person, even if they have the same symptoms you have. Enter medications to view a detailed interaction report using our Drug Interaction Checker. You may be more likely to have a broken bone while using levothyroxine. You should not use levothyroxine if you are allergic to glycerin or edetate disodium, or if you have an untreated or uncontrolled adrenal gland disorder.

• Protein-bound thyroid hormones exist in reverse equilibrium with small amounts of free hormone.
• The majority of the SYNTHROID dose is absorbed from the jejunum and upper ileum.
• When exercising their judgement, health professionals are expected to take this guidance fully into account, alongside the individual needs, preferences and values of their patients.
• SYNTHROID may reduce the therapeutic effects of digitalis glycosides.
• A 50% or greater suppression of uptake indicates a normal thyroid-pituitary axis and thus rules out thyroid gland autonomy.

Many drugs and physiologic conditions affect the binding of thyroid hormones to serum proteins see DRUG INTERACTIONS. Thyroid hormones do not readily cross the placental barrier see Use In Specific Populations. Assess the adequacy of therapy by periodic assessment of laboratory tests and clinical evaluation. Persistent clinical and laboratory evidence of hypothyroidism despite an apparent adequate replacement dose of SYNTHROID may be evidence of inadequate absorption, poor compliance, drug interactions, or a combination of these factors. SYNTHROID is indicated in adult and pediatric patients, including neonates, as a replacement therapy in primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) congenital or acquired hypothyroidism.

Response and effectiveness

Women who are post-menopausal or who use this medicine for a long time may have some bone loss, which could lead to osteoporosis. Talk with your doctor if you have questions or concerns about this. If you think you have become pregnant while using this medicine, tell your doctor right away. You may need a larger dose of levothyroxine while you are pregnant.

Levothyroxine is used in adults and children to treat hypothyroidism (underactive thyroid – a condition where the thyroid gland does not produce enough thyroid hormone). Thyroid hormones should be administered cautiously to patients in whom there is strong suspicion of thyroid gland autonomy, in view of the fact that the exogenous hormone effects will be additive to the endogenous source. Consumption of certain foods may affect SYNTHROID absorption thereby necessitating adjustments in dosing see Dosage and Administration (2.1). Soybean flour, cottonseed meal, walnuts, and dietary fiber may bind and decrease the absorption of SYNTHROID from the gastrointestinal tract. Grapefruit juice may delay the absorption of levothyroxine and reduce its bioavailability. The SYNTHROID dosage is based on the target level of TSH suppression for the stage and clinical status of thyroid cancer.

• Levothyroxine should not be used for the treatment of infertility unless it is caused by hypothyroidism.
• You may be more likely to have a broken bone while using levothyroxine.
• In a medical setting, you are not likely to miss a dose of levothyroxine injection.
• The recommended daily dosage of SYNTHROID in pregnant patients is described in Table 3.

Dr. Frieze suggests educating patients on the importance of consistent therapy & precise dosing with Synthroid. You are encouraged to report negative side effects of prescription drugs to the FDA. A portion of the conjugated hormone reaches the colon unchanged and is eliminated in the feces. Closely monitor infants during the first 2 weeks of SYNTHROID therapy for cardiac overload and arrhythmias. If cardiac symptoms develop or worsen, reduce the SYNTHROID dose or withhold for one week and buy synthroid restart at a lower dose.

The higher affinity of both TBG and TBPA for T4 partially explains the higher serum levels, slower metabolic clearance, and longer half-life of T4 compared to T3. Protein-bound thyroid hormones exist in reverse equilibrium with small amounts of free hormone. Many drugs and physiologic conditions affect the binding of thyroid hormones to serum proteins see Drug Interactions (7). Thyroid hormones do not readily cross the placental barrier see Use in Specific Populations (8.1). HypothyroidismSYNTHROID® (levothyroxine sodium) tablets, for oral use is indicated as a replacement therapy in primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) congenital or acquired hypothyroidism.