What Factors Affect Synthroid® Dosage?

Synthroid® dosage can depend on a patient’s general physical condition as well as the reason for taking the medication. This hormone, known by the generic name of levothyroxine, is a replacement for thyroid hormones used in patients with hypothyroid and other medical conditions that affect the delicate balance of the endocrine system. Patients may need to spend several weeks adjusting their dosing to determine the right amount to take, and require long-term monitoring to confirm that the dosage is still appropriate. An endocrinologist, a hormone specialist, usually oversees treatment although other care providers may be involved as well.

Patients who take this hormone usually want to reach a target range of levels for thyroid-stimulating hormone in their blood. The generally recommended range falls between 0.3 and 3.0 mili-international units (mIU) per liter. Before treatment starts, the care provider can take a blood sample for testing to learn more about the patient’s hormone levels. As the patient takes the Synthroid® dosage, repeat blood tests can monitor levels. Examinations can also evaluate the patient’s response, checking for issues like personality changes, fatigue, or skin breakouts that might be associated with changes in hormone levels.

This medication has a very narrow therapeutic index. Small changes in Synthroid® dosage can result in radical variations in hormone levels. The patient may not have enough thyroid hormones in circulation with a low dose, or could have too much with a higher dose. Some patients also appear to do better when they are slightly outside the normal range, which can only be determined on a case by case basis. For several weeks after starting Synthroid®, the patient may need to report for regular office visits to test hormone levels.

Age, weight, activity level, and genetics can all influence the way the patient processes the medication, and may necessitate small tweaks in the dosage. Furthermore, underlying medical conditions can also be an issue. These may cause levels to rise or fall unexpectedly, or could create medication conflicts that might be a cause for concern. Patients also experience hormone changes during pregnancy, menopause, and major life events that might throw off the correct Synthroid® dosage and require more adjustment.

As a patient takes Synthroid®, the doctor may recommend being cautious about side effects. Patients who notice things like appetite increase or suppression, personality changes, and skin changes may want to talk to their doctors. These could be indicators that the Synthroid® dosage is too high or low. A blood test can quickly determine the patient’s hormone levels and provide guidance for dosing adjustments.