Hyperthyroidism :
Excessive production of thyroid hormones and it is usually requires surgery, but before surgery the patient must be prepared by preliminary abolition of the hyperthyroidism through the use of antithyroid drugs.
Mechanism of action :
Prevention of the iodination of the precursors of thyroxine and triiodothyronine through inhibition of thyroid peroxidase enz.
the enzyme responsible for iodination of tyrosine residue and the coupling of iodotyrosine residue to form iodothyronines.
** Thyroxine and triiodothyronine are used as a replacement
therapy in thyroid gland deficiency.
** Thyroxine may be the storage form of the hormone, whereas
triiodothyronine is the circulating form.
triiodothyronine is the circulating form.
1- Propyithiouracil (Propacil)
** It is useful in the treatment of hyperthyroidism.
** There is a delay in appearance of its effects because it does not interfere with the activity of thyroid hormones already formed and stored in the thyroid gland.
** It is useful in the treatment of hyperthyroidism.
** There is a delay in appearance of its effects because it does not interfere with the activity of thyroid hormones already formed and stored in the thyroid gland.
** This lag period may vary from several days to weeks, depending on the condition of the patient.
2- Methimazole (Tapazole),
** It is indicated in the treatment of hyperthyroidism.
** It is more potent than propyithiouracil.
** It is indicated in the treatment of hyperthyroidism.
** It is more potent than propyithiouracil.