Synthroid (Levothyroxine Sodium)

Synthroid is a medicine used to treat hypothyroidism (an underactive thyroid gland). Synthroid is a synthetic hormone that is intended to replace a hormone that is normally produced by your thyroid gland. It is also used to treat or prevent certain other thyroid conditions such as goiter (an enlarged thyroid gland); inflammation of the thyroid gland; thyroid hormone deficiency due to surgery, radiation, or certain medications; or for the management of certain thyroid cancers.

Do not use Synthroid to treat obesity or weight loss. Synthroid is a replacement therapy, so you need to take it every day for life unless your condition is temporary. Improvement in your symptoms can be seen several weeks after you start Synthroid. Continue taking your medication as directed by your doctor. Tell your doctor immediately if you experience rapid or irregular heartbeats, chest pain, shortness of breath, leg cramps, headache, nervousness, irritability, sleeplessness, tremors, change in your appetite, weight gain or loss, vomiting, diarrhea, excessive sweating, heat intolerance, fever, changes in menstrual periods, hives, or skin rash. Long-term Synthroid use can weaken bones, especially in women after menopause. If you have heart disease, your doctor may need to start you on a lower dose of Synthroid to see how you respond to this medication. Also, if you have diabetes, your doctor will determine if the dose of your diabetes medication needs to be adjusted. Your doctor will monitor your blood sugar levels. If you are taking an oral blood thinner (such as warfarin), your doctor will monitor your blood clotting status to determine if the dose of your blood thinner needs to be adjusted. Tell your doctor or dentist that you are taking Synthroid before having any surgery. Synthroid can cause partial hair loss during the first few months of treatment. This is usually temporary.