Antithyroid drug: A drug directed against the thyroid gland. The antithyroid drugs include carbimazole, methimazole, and propylthiouracil (PTU). These drugs are used to treat hyperthyroidism (overactivity of the thyroid gland) in order to reduce the excessive thyroid activity before surgery and to treat and maintain patients not having surgery.
Carbimazole, its active metabolite methimazole, and propylthiouracil all act by inhibiting the enzyme thyroid peroxidase and in that way they block the synthesis (the production) of thyroid hormone.
About 30 to 40% of patients treated with an antithyroid drug remain euthyroid (with normal levels of thyroid hormone) 10 years after the discontinuation of antithyroid drug therapy, which means that the Graves’ disease (the most common cause of hyperthyroidism) is in remission.
A common problem with antithyroid drugs is undershooting or overshooting causing persistent hyperthyroidism or hypothyroidism. A rare complication of antithyroid therapy is agranulocytosis (decrease in white blood cells) which calls for immediate discontinuation of the drug.
Antitoxin: An antibody produced in response to and capable of neutralizing a specific biologic toxin such as those that cause diphtheria, gas gangrene, or tetanus. Antitoxins are used prophylactically and therapeutically.
Antivenin: Antibodies created in the blood of a horse or sheep when the animal is injected with snake venom. Antivenin acts by neutralizing snake venom that has entered the body. Also called antivenom, snake antivenin, or snake antivenom. Other spellings: antivenom
Antiviral: An agent that kills a virus or that suppresses its ability to replicate and, hence, inhibits its capability to multiply and reproduce. For example, amantadine (Symmetrel) is a synthetic antiviral. It acts by inhibiting the multiplication of the influenza A virus. It was used to lessen the severity of the disease, particularly in individuals […]
- Antiviral agent
Antiviral agent: A medication or another agent that kills viruses or inhibits their capability to reproduce.
Antonomasia: 1. The substitution of a title for a proper name, as in addressing a physician as “Doctor” or a nurse as “Nurse.” 2. The substitution of a personal name for a noun to designate a member of a group or class, as in calling a geneticist a Mendelist (after Gregor Mendel, who discovered the […]