A small subset of medications including glucocorticoids, dopamine agonists, somatostatin analogs and rexinoids affect thyroid function through suppression of TSH in the thyrotrope or hypothalamus. This decrease is less pronounced than the TSH suppression that occurs in hyperthyroidism. These medication effects can be difficult to distinguish from the changes of non-thyroidal illness in the setting of severe illness, where many of these medications are frequently used. Fortunately, most of these medications do not cause clinically evident central hypothyroidism. However, a newer class of nuclear hormone receptors agonists, called rexinoids, cause clinically significant central hypothyroidism in most patients and dopamine agonists may exacerbate ‘hypothyroidism’ in patients with non thyroidal illness.