On the interaction between thyroid hormones and the tranquillisers Librium and Valium.

Studies on the in vitro effects of Librium and Valium on the circulating thyroid hormones, their binding and on the binding proteins showed that Valium can affect the triiodothyronine binding capacity and free thyroxine index three times more than Librium. Valium can alter the thyroxine standards, which are needed to obtain thyroxine values in serum samples in competitive protein binding assay and can alter the distribution of radioactive thyroxine among serum proteins more than Librium which has a lesser effect on the thyroxine binding. Though these drugs affect some thyroid function tests, in vivo administration to rabbits over three months failed to alter these parameters. We have presented data suggesting that these drugs produce no changes in thyroid function (as they indeed do in some thyroid function tests).