Synthroid

Synthroid is a prescription medication that contains levothyroxine sodium. This is a synthetic version of the thyroid hormone T4, which your thyroid gland normally makes. When your thyroid does not produce enough hormone, Synthroid replaces what is missing.

Millions of people take Synthroid every day to manage hypothyroidism. This condition happens when the thyroid gland is underactive. The medication comes in tablet form and is taken once daily. Different strengths are available to match your specific hormone needs.

Synthroid works best when taken on an empty stomach, usually 30 to 60 minutes before breakfast. Consistency matters with this medication. Taking it the same way every day helps maintain steady hormone levels in your body.

• Treating hypothyroidism, or underactive thyroid
• Managing thyroid hormone levels after thyroid surgery
• Suppressing thyroid stimulating hormone in thyroid cancer patients
• Treating goiter, an enlarged thyroid gland
• Managing congenital hypothyroidism in infants and children

Synthroid replaces the thyroid hormone T4 that your body needs but cannot make enough of on its own. After you take it, your body converts some of this T4 into T3, another important thyroid hormone. These hormones control your metabolism, which affects how your body uses energy.

Thyroid hormones influence almost every cell in your body. They help regulate your heart rate, body temperature, energy levels, and weight. When levels are too low, you may feel tired, cold, or gain weight. Synthroid brings hormone levels back to normal, which helps these symptoms improve over time.

Typical starting doses range from 25 to 50 micrograms daily for adults. Some patients may need 100 to 125 micrograms or more. Your doctor will determine your exact dose based on your age, weight, and thyroid hormone levels. Doses are adjusted based on blood test results, usually checked every 6 to 8 weeks until levels stabilize. Once stable, testing happens every 6 to 12 months. Always take Synthroid exactly as prescribed by your doctor.

• Hair loss during the first few months of treatment
• Headache
• Increased appetite
• Weight changes
• Heat sensitivity or increased sweating
• Trouble sleeping
• Nervousness or irritability

Serious side effects require immediate medical attention. These include chest pain, rapid or irregular heartbeat, shortness of breath, or signs of allergic reaction. If your dose is too high, you may experience symptoms of hyperthyroidism such as tremors, anxiety, or severe sweating. Contact your doctor if side effects persist or worsen.

• Calcium supplements and antacids containing calcium or aluminum
• Iron supplements and multivitamins containing iron
• Proton pump inhibitors such as omeprazole or lansoprazole
• Cholesterol medications like cholestyramine or colestipol
• Diabetes medications, which may need dose adjustments
• Blood thinners such as warfarin
• Estrogen-containing birth control pills or hormone therapy
• Soy products, which can affect absorption
• Coffee, which may reduce absorption if taken together

Regular blood tests are essential while taking Synthroid to ensure your dose is correct. Your doctor will check your thyroid stimulating hormone, also called TSH, which shows if your thyroid medication dose is right. Free T4 levels may also be tested to see how much active thyroid hormone is in your blood. Some doctors check free T3 as well. Testing typically happens 6 to 8 weeks after starting Synthroid or changing your dose. Once your levels are stable, you will need testing every 6 to 12 months. Rite Aid offers blood testing services that measure over 200 biomarkers, including TSH, free T4, and free T3, helping you track your thyroid health between doctor visits.