Страна: Канада
Язык: английский
Источник: Health Canada
THYROID
ERFA CANADA 2012 INC
H03AA05
THYROID GLAND PREPARATIONS
60MG
TABLET
THYROID 60MG
ORAL
100
Prescription
THYROID AGENTS
Active ingredient group (AIG) number: 0107351001; AHFS:
APPROVED
2020-05-20
1 PRESCRIBING INFORMATION Pr ERFA THYROID Desiccated Thyroid C.S.D. 30, 60, 125 mg Tablets Hypothyroidism Therapy Canada, H4P 2P5 Montréal, Quebec 8250 Décarie Blvd, suite 110 Submission control No.: 238182 Date of Revision: 19-May-2020 2 PRESCRIBING INFORMATION PR ERFA THYROID DESICCATED THYROID 30, 60 AND 125 MG TABLETS THERAPEUTIC CLASSIFICATION HYPOTHYROIDISM THERAPY ACTIONS AND CLINICAL PHARMACOLOGY The principal pharmacologic effect of exogenous thyroid hormones is to increase the metabolic rate of body tissues. The normal thyroid gland contains approximately 200 µg of levothyroxine (T4)/g of gland, and 15 µg of triiodothyronine (T3)/g. The ratio of these two hormones in the circulation does not represent the ratio in the thyroid gland, since about 80% of peripheral triiodothyronine comes from monodeiodination of the outer ring of levothyroxine. Peripheral monodeiodination of levothyroxine at the 5 position (inner ring) also results in the formation of reverse triiodothyronine (r T3), which is calorigenically inactive. These facts would seem to advocate levothyroxine as the treatment of choice for the hypothyroid patient and to mitigate against the administration of hormone combinations which while normalizing thyroxine levels, may produce triiodothyronine levels in the thyrotoxic range. Triiodothyronine (T3) level is low in the fetus and newborn, in old age, in chronic caloric deprivation, hepatic cirrhosis, renal failure, surgical stress, and chronic illnesses representing what has been called the “low triiodothyronine syndrome.” Pharmacokinetics: Animal studies have shown that T4 is only partially absorbed from the gastrointestinal tract. The degree of absorption is dependent on the vehicle used for its administration and by the character of the intestinal contents, the intestinal flora, including plasma protein, soluble dietary factors, all of which bind thyroid and thereby make it unavailable for diffusion. Only 41% is absorbed when given in a gelatin capsule as opposed to a 74 percent absorpti Прочитать полный документ