Synthroid Levothyroxine Sodium: Side Effects, Uses, Dosage, Interactions, Warnings

Biotin supplementation is known to interfere with thyroid hormone immunoassays that are based on a biotin and streptavidin interaction, which may result in erroneous thyroid hormone test results. Stop biotin and biotin-containing supplements for at least 2 days prior to thyroid testing. Concurrent use of ketamine and SYNTHROID may produce marked hypertension and tachycardia.

Toxic effects may include increased risk of cardiac arrhythmias and central nervous system stimulation. Administration of sertraline in patients stabilized on SYNTHROID may result in increased SYNTHROID requirements. SYNTHROID increases the response to oral anticoagulant therapy. Therefore, a decrease in the dose of anticoagulant may be warranted with correction of the hypothyroid state or when the SYNTHROID dose is increased.

Drug Interaction Classification

So, my job as a thyroid specialist in these patients is to make sure my patient is treated and gets to a point of consistency, because it is a lifelong course of medication. Thyroid hormones exert their physiologic actions through control of DNA transcription and protein synthesis. Triiodothyronine (T3) and L-thyroxine (T4) diffuse into the cell nucleus and bind to thyroid receptor proteins attached to DNA. This hormone nuclear receptor complex activates gene transcription and synthesis of messenger RNA and cytoplasmic proteins.

NP Thyroid

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. 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. It is noteworthy that in two studies37,38 patients were switched from the tablet formulation to the liquid one while maintaining the co-ingestion of PPI and the daily dose of LT4, with a significant decrease in serum TSH levels (Table 1).

• 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.
• Dosing here should be individualized based on whether the patients were diagnosed with hypothyroidism prior to pregnancy or during the pregnancy.
• This includes prescription and over-the-counter medicines, vitamins, and herbal products.

And to adjust the dose based on periodic assessment of the patient’s clinical response and their laboratory values. The second is that Synthroid has a history, as physicians have been treating patients with hypothyroidism with Synthroid for over 65 years. Monitor for cardiac arrhythmias during surgical procedures in patients with coronary artery disease receiving suppressive SYNTHROID therapy. Monitor patients receiving concomitant SYNTHROID and sympathomimetic agents for signs and symptoms of coronary insufficiency. Administer SYNTHROID to pediatric patients who cannot swallow intact tablets by crushing the tablet, suspending the freshly crushed tablet in a small amount (5 to 10 mL) of water and immediately administering the suspension by spoon or dropper.

It’s very important to make sure that you write “Dispense as written,” or whatever state-specific language, on the prescription when you prescribe the medication. Family history is very important when talking to these patients because there is a strong predisposition amongst family members in the primary setting to have another family member with hypothyroidism. One of the difficulties of the diagnosis of hypothyroidism is that the signs and symptoms are non-specific to the disease. So, in order to diagnose the disease accurately, given the non-specific symptoms, you must use the TSH level as a screening tool to assist in the family history and signs and symptoms that you have come across. Levothyroxine is the most commonly used treatment in this setting. Circulating thyroid hormones are greater than 99% bound to plasma proteins, including thyroxine-binding globulin (TBG), thyroxine-binding prealbumin (TBPA), and albumin (TBA), whose capacities and affinities vary for each hormone.

Administer thyroid hormone products formulated for intravenous administration to treat myxedema coma. The general aim of therapy is to normalize the serum TSH level. 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. The recommended starting daily dosage of SYNTHROID in adults with primary, secondary, or tertiary hypothyroidism is based on age and comorbid cardiac conditions, as described in Table 1. For patients at risk of atrial fibrillation or patients with underlying cardiac disease, start with a lower dosage and titrate the dosage more slowly to avoid exacerbation of cardiac symptoms.

Do not administer in foods that synthroid backorder decrease absorption of SYNTHROID, such as soybean-based infant formula see DRUG INTERACTIONS. 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. Following assessment and application of eligibility criteria, seven studies were included. There was a considerable heterogeneity among the included studies in design, sample size, inclusion and exclusion criteria, treatment regimen, and baseline demographics. Each of the included studies showed an increase in TSH levels following LT4 and PPI consumption, and in the majority of these, the increase was statistically significant.

Hypothyroidism

Use the serum free-T4 level to titrate SYNTHROID dosing until the patient is clinically euthyroid and the serum free-T4 level is restored to the upper half of the normal range see Recommended Dosage And Titration. The contradictory findings mentioned may result from the limited size of the cohorts analyzed as well as differences in subjects enrolled (patients vs. healthy volunteers). The aim of this study was to assess the effect of concomitant use of levothyroxine (LT4) and proton pump inhibitors (PPIs) on thyroid-stimulating hormone (TSH) levels in patients with primary hypothyroidism. Personally, I have had experiences where I have written for brand-name SYNTHROID and the patients have been dispensed generic levothyroxine or even another branded levothyroxine product.

Monitor Closely (

So, as a reminder, SYNTHROID is indicated for the treatment of hypothyroidism. That is primary, secondary, or tertiary hypothyroidism, either due to congenital or acquired state. It is not indicated for the suppression of benign thyroid nodules, or for non-toxic defuse goiter in iodine-sufficient patients. It is also not indicated for the treatment of hypothyroidism during the recovery phase of subacute thyroiditis. There are safety considerations as SYNTHROID should not be used for treatment of obesity or for weight loss. And SYNTHROID is contraindicated in patients who have uncorrected adrenal insufficiency.