Levothyroxine: Uses, Dosage, Side Effects

Levothyroxine: Uses, Dosage, Side Effects

If you notice any other effects, check with your healthcare professional. 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. Hypothyroidism can sometimes cause infertility in men and women. Levothyroxine should not be used for the treatment of infertility unless it is caused by hypothyroidism.

Drugs That May Alter Hepatic Metabolism of T4 (Hypothyroidism)

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. Stop biotin and biotin-containing supplements for at least 2 days before assessing TSH and/or T4 levels see Drug Interactions (7.10).

The liver is the major site of degradation for both T4 and T3, with T4 deiodination also occurring at a number of additional sites, including the kidney and other tissues. Approximately 80% of the daily dose of T4 is deiodinated to yield equal amounts of T3 and reverse T3 (rT3). Thyroid hormones are also metabolized via conjugation with glucuronides and sulfates and excreted directly into the bile and gut where they undergo enterohepatic recirculation. 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). The recommended daily dosage of SYNTHROID in pregnant patients is described in Table 3.

DISCUSS THE FOLLOWING WITH PATIENTS WHEN PRESCRIBING SYNTHROID

Titrate the dosage (every 2 weeks) as needed based on serum TSH or free- T4 until the patient is euthyroid see Important Considerations For Dosing. Titrate the dosage (every 2 weeks) as needed based on serum TSH or free-T4 until the patient is euthyroid see Dosage and Administration (2.2). Titrate the dosage (every 2 weeks) as needed based on serum TSH or free-T4 until the patient is euthyroid.

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. Dosage titration is based on serum TSH or free-T4 see Important Considerations For Dosing. Upon first prescribing levothyroxine, medication adjustment should occur every 6 to 8 weeks until the patient reaches a steady state. A clinician should then order TSH and free T4 levels immediately. If the free T4 comes back elevated, the clinician should decrease the dose of levothyroxine to prevent cardiac complications and other symptoms of hyperthyroidism. Finally, clinicians should refer the patient to an endocrinologist if hypothyroidism is due to central causes.

2 Antidiabetic Therapy

Over-treatment with levothyroxine may cause an increase in heart rate, cardiac wall thickness, and cardiac contractility and may precipitate angina or arrhythmias, particularly in patients with cardiovascular disease and in elderly patients. Initiate SYNTHROID therapy in this population at lower doses than those recommended in younger individuals or in patients without cardiac disease see Dosage and Administration (2.3) and Use in Specific Populations (8.5). 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.

Monitoring TSH And/Or Thyroxine (T Levels

Primary hypothyroidism is basically diagnosed off of a screening TSH, or thyroid stimulating hormone. It may take several weeks before your body starts to respond to Synthroid. Synthroid works best if you take it on an empty stomach, 30 to 60 minutes before breakfast. synthroid calories Follow your doctor’s dosing instructions and try to take the medicine at the same time each day. You may not be able to take Synthroid if you have certain medical conditions.

• Monitor for cardiac arrhythmias during surgical procedures in patients with coronary artery disease receiving suppressive SYNTHROID therapy.
• Myxedema coma is a life-threatening emergency characterized by poor circulation and hypometabolism and may result in unpredictable absorption of levothyroxine sodium from the gastrointestinal tract.
• This hormone nuclear receptor complex activates gene transcription and synthesis of messenger RNA and cytoplasmic proteins.
• The goal is to achieve steady TSH levels within the appropriate therapeutic range.
• Using this medicine with any of the following may cause an increased risk of certain side effects but may be unavoidable in some cases.

Significant – Monitor Closely

Tell your doctor if you are pregnant or plan to become pregnant. Having hypothyroidism during pregnancy may increase the risk of premature birth or other complications. The benefit of treating hypothyroidism may outweigh any risks to the baby.

Synthroid During Pregnancy and Breastfeeding

Thyroid hormones, including SYNTHROID, either alone or with other therapeutic agents, should not be used for the treatment of obesity or for weight loss. In euthyroid patients, doses within the range of daily hormonal requirements are ineffective for weight reduction. Larger doses may produce serious or even life-threatening manifestations of toxicity, particularly when given in association with sympathomimetic amines such as those used for their anorectic effects.

Using this medicine with any of the following may cause an increased risk of certain side effects but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco. Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals.