Nifedipine induced modulations of intra-thyroidal radio-iodine turnover kinetics in euthyroid and thyrotoxic patients.

Nifedipine induced modulations of intrathyroidal radioiodine turnover kinetics has been studied in euthyroid and thyrotoxicosis individuals. Nifedipine has been found to suppress Amax significantly (p < 0.001), while transit kinetics k1 and k2 are not significantly affected. On the contrary, in the patients with thyrotoxicosis post-nifedipine Amax was not significantly different from pre-nifedipine study, while k1 was slightly suppressed (p < 0.05) and k2 was significantly elevated (p < 0.01). Apparently different Ca+2 dependent control mechanisms are operative in euthyroid and thyrotoxic states. Clinical implications of these observations have been discussed.