Levothyroxine or L-thyroxine is a synthetic form of the thyroid hormone thyroxine. In its natural form, thyroxine is also in its L-form. This synthetic hormone is used as a supplement for hypothyroid patients who are incapable of producing sufficient quantities of thyroid hormone to maintain normal physiologic functions.
Indications and Contraindications Around forty percent of doctors recommend this synthetic hormone for the treatment of solitary thyroid nodules but there are some instances when its administration is deemed inappropriate. One of the factors to be considered in prescribing thyroid-hormone-suppressive therapy in a patient with thyroid nodules is the patient’s age. Patients above the age of 60 years old and postmenopausal women are at risk for the adverse outcomes of this hormone. Also, benign thyroid nodules in advanced age are characterized by little growth if at all. Levothyroxine may be effective in diminishing the size of small, recently diagnosed nodules with an abundance of colloid. It has been hypothesized that the hormone could aid in the prevention of the formation of more follicles but this has yet to be verified. Because of this, it is generally not recommended for benign thyroid nodules.
Rationale: How It Works The activity of the thyroid gland is mostly stimulated by the secretion of thyroid-stimulating hormone or TSH by the pituitary gland. In cases of patients unable to react properly to the stimulus, the thyroid continues to swell as it gets even more irritated despite its continued inability to produce sufficient quantities of thyroid hormone. Because there is still very little concentration of thyroid hormone in the body, the pituitary gland continues to release more TSH to up the thyroid hormone production but to no avail. This only causes more follicles to grow in the thyroid without releasing any hormone at all. Administration of thyroxine or a synthetic form of the hormone will not only provide relief from the symptoms of hypothyroidism, its presence will also signal the pituitary gland to secrete less and less of the thyroid-stimulating hormone. Without the unnecessary pressure exerted by increased levels of TSH to aggravate the thyroid gland, it starts to recede in size.
Efficacy: Does It Work? There have been conflicting studies on whether levothyroxine is indeed effective in shrinking benign thyroid nodules. One such study states that there was a significant effect on patients after treatment with the hormone, whereas another would state that the hormone was ineffective. Another study indicates that treatment with the hormone resulted in a significant reduction in the thyroid nodules with consequent prevention in the formation of new Synthroid Cost. A subset of benign thyroid nodules were found to react favorably in response to levothyroxine but the markers for this subset are yet undefined. However, it has been observed that solid nodules do respond more to the hormone than cystic nodules. Also, smaller nodules and nodules filled with colloid are found to be affected by the synthetic hormone.
