Iode stable et prévention de la contamination par les iodes radioactifs : données pharmacologiques et pharmaceutiques

More or less rapid radio-induction of thyroidian cancers is the main pathological consequence of an accidental exposure to ingested or inhaled radioactive iodines following a nuclear power plant accident. The prophylactic administration of potassium iodine in a single oral dose has to be practiced as soon as possible after the nuclear accident. The efficacy of this therapy depends on pharmacokinetics of radioidines. Iodines are rapidly and completely absorbed as iodides. The radioactive iodines, mainly iodine 131, concentrate in the thyroid gland because of a carrier-mediated transport by the Na-I symporter. Administration of stable iodine results in the symporter blockade, which limits the uptake of radioactive iodines by the thyroid and the duration of the internal irradiation. This irradiation will never exceed 3 days if the therapy is started between 6 h before the accidental exposure and 1 h after. The pharmacist asked to dispense the tablets of stable iodine has a important place because, besides his advices on the optimal modalities of taking stable iodine and the risks of unwanted effects, he extend these advices to information on the radioactive risk and on measures of civil and sanitary protection.