CHLORDIAZEPOXIDE (Librium), a newly synthesized psychotherapeutic agent, became available in 1959. During the past year, several attending physicians at this institution commented that the protein bound iodine and radioactive iodine uptakes tended to be low in several of their patients who were taking chlordiazepoxide. A review of the literature yielded no direct information. Shackleford1 stated: "Chlordiazepoxide appears to potentiate some medications, and may exert an antithyroid effect." Boris et al concluded that chlordiazepoxide does not possess antithyrotropic effects in rats.2 It was believed that a study of the effect of this drug on thyroid function in man was indicated.
Healthy volunteers and patients who were to remain in the hospital for a minimal stay of 10 days were selected for this study. Patients with thyroid, liver, renal, or heart disease were rejected, as were subjects who had been exposed to iodine in any form or had received