Because thyroid hormone is highly protein bound, medical conditions that alter the amount of binding hormones and drugs that compete for binding may change the amount of available free thyroid hormone.

The thyroid replacement dosage must be changed in response to alterations in binding status. With conditions that cause an increase in serum binding proteins, such as high estrogen states e. In contrast, androgens decrease levels of thyroid binding proteins, necessitating a reduction in the dosage.

Older patients also have lower serum protein levels and may require reductions in their maintenance dosage over time. Nephrosis, protein-losing enteropathies and cirrhosis are other conditions that require a reduced thyroid hormone dosage.

A number of medications reduce the absorption of thyroid hormone from the intestines, necessitating an increase in the replacement dosage Table 4.

When these medications are started or adjusted, the TSH value should be monitored to determine whether additional thyroid hormone replacement is indicated.

Poor compliance is the most common reason for continued elevation of the TSH level in patients receiving presumably adequate thyroid hormone replacement.

Very rarely, patients have tissue-level unresponsiveness to thyroid hormone. This condition reflects a mutation in the gene that controls a receptor for T 3 , rendering it unable to bind with the hormone.

The genetic mutation has been identified in only families. Consequently, the TSH level remains elevated, and the patients continue to have symptoms of hypothyroidism.

These patients should be referred to an endocrinologist for further evaluation and management. The U. Preventive Services Task Force 23 does not recommend routine screening for hypothyroidism in asymptomatic persons.

Recently, some expert panels 24 noted that screening may be beneficial in high-risk populations such as elderly women.

However, widespread screening is not likely to be cost-effective. Because of the nonspecific symptoms of hypothyroidism, many patients would be tested because of their symptoms. This practice should not be confused with asymptomatic screening. Sawin CT, Chopra D, Azizi F, Mannix JE, Bacharach P.

The aging thyroid. Increased prevalence of elevated serum thyrotropin levels in the elderly. Hueston WJ. Thyroid disease. In: Rosenfeld JA, Alley N, Acheson LS, Admire JB, eds. Women's health in primary care.

Farwell AP, Braverman LE. Inflammatory thyroid disorders. Otolaryngol Clin North Am. Schubert MF, Kountz DS. A disease with many faces. Postgrad Med. Larsen PR, Davies TF, Hay ID. The thyroid gland. In: Wilson JD, Foster DW, Kronenberg HM, Larsen PR, eds. Williams Textbook of endocrinology.

Philadelphia: Saunders, Dong BJ, Hauck WW, Gambertoglio JG, Gee L, White JR, Bubp JL, et al. Bioequivalence of generic and brand-name levothyroxine products in the treatment of hypothyroidism. Singer PA, Cooper DS, Levy EG, Ladenson PW, Braverman LE, Daniels G, et al.

Treatment guidelines for patients with hyperthyroidism and hypothyroidism. Standards of Care Committee, American Thyroid Association. Grebe SK, Cooke RR, Ford HC, Fagerstrom JN, Cordwell DP, Lever NA, et al.

Treatment of hypothyroidism with once weekly thyroxine. J Clin Endocrinol Metab. Bunevicius R, Kazanavicius G, Zalinkevicius R, Prange AJ. Effects of thyroxine as compared with thyroxine plus triiodothyronine in patients with hypothyroidism. N Engl J Med. Carr D, McLeod DT, Parry G, Thornes HM.

Fine adjustment of thyroxine replacement dosage: comparison of the thyrotrophin releasing hormone test using a sensitive thyrotrophin assay with measurement of free thyroid hormones and clinical assessment. Clin Endocrinol [Oxf].

Rosenbaum RL, Barzel US. Levothyroxine replacement dose for primary hypothyroidism decreases with age. Ann Intern Med. Sawin CT, Geller A, Hershman JM, Castelli W, Bacharach P.

The use of thyroid hormone in older persons. Hays MT, Nielsen KR. Human thyroxine absorption: age effects and methodological analyses. Wallace K, Hoffman MT. Thyroid dysfunction: how to manage overt and subclinical disease in older patients.

Pines A, Dotan I, Tabori U, Villa Y, Mijatovic V, Leno Y, et al. l-Thyroxine prevents the bone-conserving effect of HRT in postmenopausal women with subclinical hypothyroidism. Gynecol Endocrinol. Hanna FW, Pettit RJ, Ammari F, Evans WD, Sandeman D, Lazarus JH.

Effect of replacement doses of thyroxine on bone mineral density. Hussein WI, Green R, Jacobsen DW, Fairman C. Normalization of hyperhomocysteinemia with l-Thyroxine in hypothyroidism.

Green R, Chong YY, Jacobsen DW, Robinson K, Gupta M. Serum homocysteine is high in hypothyroidism: a possible link with coronary artery disease.

Presented at the International Conference on Homocysteine Metabolism, from Basic Science to Clinical Medicine. Ireland, July 2—5, Ir J Med Sci. Refetoff S, Weiss RE, Usala SJ. The syndromes of resistance to thyroid hormone.

Endocr Rev. Guide to clinical and preventive services: report of the U. Preventive Services Task Force. Helfand M, Redfern CC. Clinical guideline, part 2. Screening for thyroid disease: an update. American College of Physicians. This content is owned by the AAFP.

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search close. PREV Nov 15, NEXT. Signs and Symptoms. Thyroid Hormone Replacement. Conditions Affecting Thyroid Hormone Replacement Requirements. Persistently Elevated TSH Despite Thyroid Hormone Replacement. Drugs and thyroid function. Screening for Hypothyroidism.

Overactive reflexes. Rapid or irregular pulse. Eye changes. Warm, moist skin. Your provider also examines your thyroid gland as you swallow to see if it's larger than usual, bumpy or tender.

Blood tests. Blood tests that measure the hormones T-4 and T-3 and thyroid-stimulating hormone TSH can confirm a diagnosis of hyperthyroidism. A high level of T-4 and a low level of TSH is common in people with hyperthyroidism. Blood tests are particularly important for older adults because they may not have classic symptoms of hyperthyroidism.

Thyroid blood tests may give false results if you take biotin. Biotin is a B vitamin supplement that also may be found in multivitamins.

Tell your health care provider if you are taking biotin or a multivitamin with biotin. To make sure your blood test is accurate, your health care provider may ask you to stop taking biotin 3 to 5 days before the test. If blood test results show hyperthyroidism, your health care provider may suggest one of the following tests.

They can help find out why your thyroid is overactive. Radioiodine scan and uptake test. For this test, you take a small, dose of radioactive iodine, called radioiodine, to see how much of it collects in your thyroid gland and where it collects in the gland.

If your thyroid gland takes in a high amount of radioiodine, that means your thyroid gland is making too much thyroid hormone. The most likely cause is either Graves' disease or overactive thyroid nodules. If your thyroid gland takes in a low amount of radioiodine, that means hormones stored in the thyroid gland are leaking into the bloodstream.

In that case, it's likely that you have thyroiditis. There are several treatments available for hyperthyroidism. The best approach for you depends on your age and health. The underlying cause of hyperthyroidism and how severe it is make a difference too.

Your personal preference also should be considered as you and your health care provider decide on a treatment plan. Treatment may include:. Anti-thyroid medicine. These medications slowly ease symptoms of hyperthyroidism by preventing the thyroid gland from making too many hormones.

Anti-thyroid medications include methimazole and propylthiouracil. Symptoms usually begin to improve within several weeks to months.

Treatment with anti-thyroid medicine typically lasts 12 to 18 months. After that, the dose may be slowly decreased or stopped if symptoms go away and if blood test results show that thyroid hormone levels have returned to the standard range.

For some people, anti-thyroid medicine puts hyperthyroidism into long-term remission. But other people may find that hyperthyroidism comes back after this treatment. Although rare, serious liver damage can happen with both anti-thyroid medications. But because propylthiouracil has caused many more cases of liver damage, it's generally used only when people can't take methimazole.

A small number of people who are allergic to these medicines may develop skin rashes, hives, fever or joint pain. They also can raise the risk of infection. This is surgery to remove part of or all of the thyroid gland.

It is not used often to treat hyperthyroidism. But it may be an option for people who are pregnant. It also may be a choice for those who can't take anti-thyroid medicine and don't want to or can't take radioiodine therapy.

Risks of this surgery include damage to the vocal cords and parathyroid glands. The parathyroid glands are four tiny glands on the back of the thyroid. They help control the level of calcium in the blood. People who have a thyroidectomy or radioiodine therapy need lifelong treatment with the medicine levothyroxine Levoxyl, Synthroid, others.

It supplies the body with thyroid hormones. If the parathyroid glands are removed during surgery, medicine also is needed to keep blood calcium in a healthy range. If you have thyroid eye disease, you may be able to manage mild symptoms with self-care steps, such as artificial tear drops and lubricating eye gels.

Avoiding wind and bright lights can help too. More-severe symptoms may need treatment with medicine called corticosteroids, such as methylprednisolone or prednisone. They can lessen swelling behind the eyeballs. The medicine teprotumumab Tepezza also may be used to control moderate to severe symptoms.

If those medicines don't ease symptoms, other medicines are sometimes used to treat thyroid eye disease. They include, tocilizumab Actemra , rituximab Rituxan and mycophenolate mofetil Cellcept.

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Along with your treatment, your health care provider might suggest that you reduce iodine in your diet. It can make hyperthyroidism worse. Kelp, dulse and other types of seaweed contain a lot of iodine.

Cough syrup and multivitamins also may contain iodine. If you have Graves' disease that causes eye or skin problems, taking the following steps may help ease symptoms:.

If you've been diagnosed with hyperthyroidism, it's important that you get the medical care you need.