This article offers a synopsis of detailed analysis of the functional and structural changes in muscle tissue in manifest and subclinical hypothyroidism. There is a brief overview of the division between mypathy and myositis, with emphasis on endocrinological and metabolic disorders. The necessity of endocrinological examination in each case of myopathy the etiology of which is indefinite is stressed, and this especially before the instigation of non-specific immunosuppressive treatment (e.g., corticosteroids) as this treatment has the risk of undesirable side-effects. In conclusion, it emphasises the negative influence of the nexus of hypothyroidism and the adminis- tering of a hypolipidemic in tandem on muscle tissue, as in rare cases this can lead to the disinegration of muscle tissue, i.e., rhabdomyolysis. The administering of hypolipidemic drugs to patients with hypothyroidism is indicated only in those cases where persists hyperlipoproteinemia after the normalisation of the thyroid function by substitutional treatment.

        Key words: Hyperlipoproteinemia - Hypolipidemic drugs - Hypothyroidism - Myopathy - Rhabdo- myolysis