Multiple sclerosis, interferon beta and clinical thyroid dysfunction.

The objective of this study was to investigate frequency and presentation of clinical thyroid dysfunction in patients treated with interferon beta (IFN-beta). We have collected the cases of clinical thyroid dysfunction in 700 consecutive patients receiving IFN-beta for multiple sclerosis (MS). Five patients (four women, one man) treated with IFN-beta1b developed hyperthyroidism.