Human Thyrotoxicosis: Response to Para-Aminobenzoic Acid.

Abstract

The use of thiourea and especially of thiouracil in the treatment of hyperthyroidism was first suggested by Astwood. Aparently, these compounds prevent thyroid hormone synthesis and numerous papers have appeared showing that they are effective in mild or moderately severe cases of thyrotoxicosis and in the preoperative preparation of patients for thyroidectomy. The disagreeable taste of thiourea makes thiouracil the preferred therapeutic agent, although the latter has been demonstrated clinically to give untoward reactions, including agranulocytosis, myxedema, skin eruptions, fever, and jaundice.5,6 Indeed, according to a most recent report, “Thiouracil is an effective drug for the treatment of thyrotoxicosis. It is also an unpredictable toxic drug which may produce serious and uncontrollable effects, especially on the bone marrow and liver.” In view of the ever increasing clinical application of chemical substances in the treatment of toxic goiter, the results obtained with para-aminobenzoic acid (PABA) are deemed of value to the investigators and clinicians in the field. Although PABA had been investigated experimentally, there have been no reports as to its use in human thyrotoxicosis. The present communication sketches 3 cases with some detail and gives numerical data obtained with 6 patients in tabular form. My interest in the use of PABA for this purpose was aroused during the first half of 1943 when I began employing its sodium salt parenterally in large doses in the treatment of a case of vitiligo. The patient was a 34-year-old woman (See Table I, Case 1-F.H.) Who had lost about 10 kg in the course of a year. Because of a few small patches of vitiligo on her hands, she was given injections of 1/2 g of the sodium salt of PABA every other day for about one week and then 11/2. g 6 times weekly.