Thyroid Hormone Replacement Therapy

54% of prescriptions for SYNTHROID were not protected with a DAW or state-specific language in one study. Particularly when SYNTHROID is written in a non-protective manner for the state language. Most, but not all, levothyroxine products have been determined to be therapeutically equivalent synthroid tiredness by the FDA. I go over with them the fact that they should check the label at the pharmacy, on the bottle, to make sure it says brand-name SYNTHROID and not generic levothyroxine. And in many cases, to also pop the top off the bottle while they are at the pharmacy counter and look at the pills and make sure they have SYNTHROID embossed on those tablets.

Congenital Hypothyroidism

These include urticaria, pruritus, skin rash, flushing, angioedema, various gastrointestinal symptoms (abdominal pain, nausea, vomiting and diarrhea), fever, arthralgia, serum sickness, and wheezing. For adult patients with primary hypothyroidism, titrate until the patient is clinically euthyroid and the serum TSH returns to normal see Dosage and Administration (2.3). 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. Once the patient and I have decided that thyroid hormone replacement is necessary, we go over the specific reasons for choosing and writing Synthroid as that replacement therapy. I review with the patients the important issues about how to take the medication, as consistency is really the key message. I talk about the fact that it’s important to take the medication in the same timing and pattern each day, take it on an empty stomach minutes before they eat.

2 Cardiac Adverse Reactions in the Elderly and in Patients with Underlying Cardiovascular Disease

Therefore, the dose of SYNTHROID used for TSH suppression should be individualized based on the specific disease and the patient being treated. Pseudotumor cerebri and slipped capital femoral epiphysis have been reported in children receiving levothyroxine therapy. Overtreatment may result in craniosynostosis in infants and premature closure of the epiphyses in children with resultant compromised adult height. The patient should be monitored closely to avoid undertreatment and overtreatment. Undertreatment may result in poor school performance due to impaired concentration and slowed mentation and in reduced adult height.

Use In Specific Populations

Familial hyper- or hypo-thyroxine binding globulinemias have been described, with the incidence of TBG deficiency approximating 1 in 9000. Adequacy of therapy should be assessed by measuring serum free- T4 levels, which should be maintained in the upper half of the normal range in these patients. Oral levothyroxine sodium is a synthetic T4 hormone that exerts the same physiologic effect as endogenous T4, thereby maintaining normal T4 levels when a deficiency is present. 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.

• These include urticaria, pruritus, skin rash, flushing, angioedema, various GI symptoms (abdominal pain, nausea, vomiting and diarrhea), fever, arthralgia, serum sickness and wheezing.
• This hormone nuclear receptor complex activates gene transcription and synthesis of messenger RNA and cytoplasmic proteins.
• Biochemical assessment incorporated measurement of serum TSH, T3, and T4.
• Central and peripheral increased sympathetic activity may be treated by administering β-receptor antagonists, e.g., propranolol, provided there are no medical contraindications to their use.

4 Monitoring TSH and/or Thyroxine (T Levels

Patients need to feel comfortable to alert me of any changes in their status in terms of their symptoms. But also specific medical changes that may indicate there may be a need for a dose change or something that could have affected their thyroid hormone levels. There are certain populations where we pay closer attention to thyroid medication dosing. Another group is those that have underlying cardiac disease or are at risk for atrial fibrillation. Concurrent use of ketamine and levothyroxine sodium tablets may produce marked hypertension and tachycardia.

Patient Counseling Information

Delays in diagnosis and institution of therapy may have deleterious effects on the child’s intellectual and physical growth and development. Rapid restoration of normal serum T4 concentrations is essential for preventing the adverse effects of congenital hypothyroidism on intellectual development as well as on overall physical growth and maturation. Therefore, SYNTHROID therapy should be initiated immediately upon diagnosis and is generally continued for life. The therapeutic effects of digitalis glycosides may be reduced by levothyroxine. Serum digitalis glycoside levels may be decreased when a hypothyroid patient becomes euthyroid, necessitating an increase in the dose of digitalis glycosides (see Table 2).

And, as a practicing thyroid specialist, I have extensive clinical experience with using this medication. So, getting the patients on the right dose, but maintaining them on the right dose, is also very important. Primary hypothyroidism is basically diagnosed off of a screening TSH, or thyroid stimulating hormone.

Levothyroxine sodium should be reduced in dose or temporarily discontinued if signs or symptoms of overdosage occur. During the first 2 weeks of SYNTHROID therapy, infants should be closely monitored for cardiac overload, arrhythmias, and aspiration from avid suckling. The list of drug-thyroidal axis interactions in Table 2 may not be comprehensive due to the introduction of new drugs that interact with the thyroidal axis or the discovery of previously unknown interactions. 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. It’s very important to remind the patients, in addition to these factors, that they need to check their pills on a consistent basis.

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 Dosage and Administration ( 2.3). The adequacy of therapy is determined by periodic assessment of appropriate 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 decreased T4 potency of the drug product. Regardless of the indication for use, careful dosage titration is necessary to avoid the consequences of over- or under-treatment.

The 50 mcg tablets are white, capsule-shaped, scored tablets debossed with L to the left of the score and to the right of the score on one side of the tablet and M on the other side. The diagnosis of hypothyroidism is confirmed by measuring TSH levels using a sensitive assay (second generation assay sensitivity ≤ 0.1 mIU/L or third generation assay sensitivity ≤ 0.01 mIU/L) and measurement of free-T4. Seizures have been reported rarely with the institution of levothyroxine therapy. SYNTHROID is contraindicated in patients with uncorrected adrenal insufficiency see Warnings and Precautions (5.4). Assess the adequacy of therapy by periodic assessment of laboratory tests and clinical evaluation.