title: The replacement therapy problem in hypothyroidism.
abstract: There is increasing evidence from studies of heart rate, liver enzyme activity, bone density and urinary sodium excretion that standard replacement therapy doses of thyroxine which suppress TSH secretion are associated with changes in target organ function similar to, but less marked than, those recorded in overt hyperthyroidism. There is also evidence that in subclinical hypothyroidism it is not only the pituitary thyrotroph which recognizes a minor reduction in serum thyroid hormone levels within the normal range. Although there is no proof that slight 'overtreatment' with thyroxine or non-treatment of subclinical hypothyroidism is detrimental to the patient in the long term, the appropriate studies have not been performed. It would seem good clinical practice, however, to treat all grades of thyroid failure and to ensure, if possible, that the dose of thyroxine is adjusted to maintain a normal and detectable TSH level when measured by a sensitive assay system. It must be conceded, however, that with the vagaries of human nature there is always likely to be greater morbidity from patients with hypothyroidism failing to take their medication regularly, than from failure by the medical attendant to make minor adjustments to the dose of thyroxine.
authors.forename: P J
authors.initials: PJ
authors.lastname: Leslie
authors.forename: A D
authors.initials: AD
authors.lastname: Toft
mesh_terms: D006801:Humans; D007037:Hypothyroidism / Q000188:drug therapy*; D013974:Thyroxine / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*
chemical_list: D013974:Thyroxine