Hypothyroidism Hashimoto’s Disease
Thyroid hormone increases metabolic clearance of glucocorticoids. Initiation of thyroid hormone therapy prior to initiating glucocorticoid therapy may precipitate an acute adrenal crisis in patients with adrenal insufficiency. Treat patients with adrenal insufficiency with replacement glucocorticoids prior to initiating treatment with SYNTHROID see CONTRAINDICATIONS. If you’re feeling good and your blood tests are stable on a generic form of levothyroxine, by all means, continue to use that preparation. You are more likely to experience ill effects by changing to a brand-name product.
When you are receiving this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive. Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines.
Drug-Food Interactions
- Furthermore, he believes that the American Thyroid Association and such laboratory organizations as the American Association for Clinical Chemistry’s AACC Academy need to carefully consider and agree on a clinical decision limit for TSH.
- Studies to evaluate mutagenic potential and animal fertility have not been performed.
- Others have found that switching from Synthroid to a generic may make it harder to maintain tight control of your thyroid hormone levels.
- It may take several weeks before you notice a change in your symptoms.
- However, recent research suggests that levothyroxine has no benefit in patients who initiate treatment when their levels are naturally under 7.0 mIU/L.
- You are encouraged to report negative side effects of prescription drugs to the FDA.
For instance, the switching examined was not restricted to LT4 formulations that were A/B rated to Synthroid® but, rather, considered all switches among LT4 formulations which were found in these data that are reflective of clinical practice. Further, the analyses may underestimate the true incidence of switching as the study only evaluated patients who were compliant users of Synthroid® during the lead-in period. The clinical outcome of interest, i.e., a diagnosis in the post-period, may not have represented an incident case; for some individuals the diagnosis was present before the switch.
Levothyroxine (a thyroid hormone) should not be used alone or along with other treatments to treat obesity or cause weight loss. If the second test shows high TSH but T-4 and T-3 are in the standard range, then the diagnosis is a condition called subclinical hypothyroidism. The first blood test typically done to diagnose hypothyroidism measures the level of thyroid-stimulating hormone (TSH) in the blood. If it’s high, the test is done again, along with a blood test for the thyroid hormone T-4.
Adverse Reactions In Pediatric Patients
Despite its reported safety, some studies in the past had suggested that generic levothyroxine was linked to an increased risk of cardiovascular disease when compared to Synthroid. Generic drugs help reduce treatment costs while generally delivering equal (non-inferior) results. However, there is debate as to whether generic levothyroxine is equally effective as the brand name version, Synthroid, in treating hypothyroidism. Because of the increased prevalence of cardiovascular disease among the elderly, initiate SYNTHROID at less than the full replacement dose see DOSAGE AND ADMINISTRATION and WARNINGS AND PRECAUTIONS. Atrial fibrillation is the most common of the arrhythmias observed with levothyroxine overtreatment in the elderly. Concurrent use of sympathomimetics and SYNTHROID may increase the effects of sympathomimetics or thyroid hormone.
Patient Handout
Because some preparations of the drug may contain iodine or lactose, patients should tell their doctors about such allergies or reactions to these components. In general, however, studies comparing generic and brand name formulations of levothyroxine fail to definitively show advantages of one preparation over another. The study’s authors looked at hypothyroidism patients between January 2008 and March 2016 who were started on either Synthroid or generic levothyroxine within a year of being diagnosed. If you switch from a brand-name to a generic preparation, you may notice that you don’t feel as well on the generic drug. And you may develop symptoms of hypothyroidism or hyperthyroidism, such as fatigue, numbness or tingling in your hands, whole-body soreness, or dry skin.
Pregnancy
T4 absorption is increased by fasting, and decreased in malabsorption syndromes and by certain foods such as soybeans. In addition, many drugs and foods affect T4 absorption see DRUG INTERACTIONS. TSH may not normalize in some patients due to in utero hypothyroidism causing a resetting of pituitary-thyroid feedback. Assess compliance, dose of medication administered, and method of administration prior to increasing the dose of SYNTHROID see WARNINGS AND PRECAUTIONS and Use In Specific Populations.
- All authors participated in the study design, analysis and interpretation of data, and writing, reviewing and approving the publication.
- Levothyroxine is used to treat hypothyroidism (condition where the thyroid gland does not produce enough thyroid hormone).
- According to the analysis of over 87,000 people on either Synthroid or generic levothyroxine, there were no differences in the rate of heart attack, heart failure, atrial fibrillation, or stroke in either group.
- The signs and symptoms of overdosage are those of hyperthyroidism see WARNINGS AND PRECAUTIONS and Adverse Reactions.
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. 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. Concurrent use of tricyclic (e.g., amitriptyline) or tetracyclic (e.g., maprotiline) antidepressants and SYNTHROID may increase the therapeutic and toxic effects of both drugs, possibly due to increased receptor sensitivity to catecholamines.
Using alcohol or tobacco with certain medicines may also synthroid paranoid cause interactions to occur. “The emerging evidence is very concerning because we’re actively giving patients a drug that they don’t need that can have potentially severe side effects, especially in elderly individuals over 80,” says El-Khoury. AbbVie, Inc. provided financial support for this study, the Open Access Fee and the Rapid Service Fee. AbbVie participated in the study design, research, data collection, analysis, and interpretation of data, writing, reviewing, and approving the publication. Generic drugs generally, but not always, cost less than their brand-name counterparts.
Decreased Bone Mineral Density Associated With Thyroid Hormone Over-Replacement
Levothyroxine works by supplementing the low hormone levels with exogenous T4. Absorption of orally administered T4 from the gastrointestinal tract ranges from 40% to 80%. The majority of the SYNTHROID dose is absorbed from the jejunum and upper ileum. The relative bioavailability of SYNTHROID tablets, compared to an equal nominal dose of oral levothyroxine sodium solution, is approximately 93%.
