This medication prevents the thyroid gland from producing thyroid hormone. It is used to treat hyperthyroidism (overactive thyroid gland) and to prepare the thyroid for surgery.

Off-label use is the practice of prescribing pharmaceuticals for a purpose outside the scope of a drug's approved label - an unproven, untested use - most often concerning the drug's indication. In the United States, the Food and Drug Administration (FDA) requires numerous clinical trials to prove a drug's safety and efficacy in treating a given disease or condition. If satisfied that the drug is safe and effective, the drug's manufacturer and the FDA agree on specific language describing dosage, route and other information to be included on the drug's label. More detail is included in the drug's package insert.

However, once the FDA approves a drug for prescription use, they do not attempt to regulate the usage of the medicine, and so the physician makes decisions based on her or his best judgment. It is legal in the United States and in many other countries to use drugs off-label, including controlled substances such as opiates, even though it is a common misconception that it is unlawful to do so. Actiq, for example, is commonly prescribed off-label even though it is a Schedule II controlled substance. However, it is unlawful to market, advertise or otherwise promote the off-label use of drugs, including controlled substances.

Off-label use of medications is very common. Up to one-fifth of all drugs are prescribed off-label and amongst psychiatric drugs, off-label use rises to 31% (Radley, et al. 2006).[1] New drugs are often not tested for safety and efficacy specifically in children. Therefore, it is believed that 50-75% of all medications prescribed by pediatricians in the U.S. are for off-label applications.[2]

Some drugs are used more frequently off-label than for their original, FDA-approved indications. A 1991 study by the U.S. General Accounting Office found that one-third of all drug administrations to cancer patients were off-label, and more than half of cancer patients received at least one drug for an off-label indication. A 1997 survey of 200 cancer doctors by the American Enterprise Institute and the American Cancer Society found that 60% of them prescribed drugs off-label. [3]. Frequently, the standard of care for a particular type or stage of cancer involves the off-label use of one or more drugs. An example is the use of tricyclic antidepressants to treat neuropathic pain. This old class of antidepressants is now rarely used for clinical depression due to side effects, but the tricyclics are often effective for treating pain.

It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly and to check for unwanted effects.

It may take several days or weeks for this medicine to work. However, do not stop taking this medicine without first checking with your doctor . Some medical problems may require several years of continuous treatment.

Before having any kind of surgery (including dental surgery) or emergency treatment, tell the medical doctor or dentist in charge that you are taking this medicine .

Check with your doctor right away if you get an injury, infection, or illness of any kind . Your doctor may want you to stop taking this medicine or change the amount you are taking.

Tapazole may cause drowsiness, dizziness, or lightheadedness. These effects may be worse if you take it with alcohol or certain medicines. Use Tapazole with caution. Do not drive or perform other possibly unsafe tasks until you know how you react to it.
Lab tests, including thyroid and liver function tests, complete blood cell counts, and blood clotting tests (eg, PT, INR), may be performed while you use Tapazole . These tests may be used to monitor your condition or check for side effects. Be sure to keep all doctor and lab appointments.
PREGNANCY and BREAST-FEEDING: Tapazole has been shown to cause harm to the fetus. If you think you may be pregnant, contact your doctor. You will need to discuss the benefits and risks of using Tapazole while you are pregnant. Tapazole is found in breast milk. Do not breast-feed while taking Tapazole .