التداخل بين إستروجينات مقترنة وليفوثيروكسين

…1: Drugs That May Alter T 4 and Triiodothyronine (T 3 ) Serum Transport Without Effecting Free Thyroxine (FT 4 ) Concentration (Euthyroidism) Drug or Drug Class Effect Clofibrate Estrogen-containing oral contraceptives Estrogens (oral) Heroin/Methadone 5-Fluorouracil Mitotane Tamoxifen These drugs may increase serum thyroxine-binding globulin (TBG) concentration.

Pregnancy, infectious hepatitis, estrogens, estrogen containing oral contraceptives, and acute intermittent porphyria increase TBG concentrations.

Hypothyroidism Estrogen administration leads to increased thyroid-binding globulin (TBG) levels.

Women with normal thyroid function can compensate for the increased TBG by making more thyroid hormone, thus maintaining free T 4 and T 3 serum concentrations in the normal range.

Women dependent on thyroid hormone replacement therapy who are also receiving estrogens may require increased doses of their thyroid replacement therapy.

These women should have their thyroid function monitored in order to maintain their free thyroid hormone levels in an acceptable range.

Increased thyroid-binding globulin (TBG) leading to increased circulating total thyroid hormone, as measured by protein-bound iodine (PBI), T 4 levels (by column or by radioimmunoassay) or T 3 levels by radioimmunoassay.