TOXIC AND DRUG INDUCED MYOPATHIES

Marinos C Dalakas (1)

1 Imperial College London

Although the “do no harm” dogma of Hippocrates is faithfully followed by all practitioners, drugs used for therapeutic interventions either alone or in combination, may sometimes cause unexpected toxicity to the muscles, resulting in a varying degree of symptomatology, from mild discomfort and inconvenience to permanent damage and disability. The clinician should suspect a toxic myopathy when a patient without a pre-existing muscle disease develops myalgia, fatigue, weakness, or myoglobinuria, temporally connected to the administration of a drug or exposure to a myotoxic substance. Myotoxic agents can cause a myopathy by: a) directly affecting a muscle organelle, such as mitochondria, lysosomes, myofibrillar proteins; b) altering muscle antigens, thereby inducing an immunologic or inflammatory reaction; and c) inducing systemic effects, such as electrolyte disturbances, nutritional deprivation or malabsorption, which secondarily affect the muscle function. The review provides an update on the drugs with well documented myocytoxicity and cautions the clinicians to be alert for the potential toxicity of newly marketed drugs; highlights the clinical features and pathomechanisms of the induced muscle disease; and offers guidance on how best to treat and distinguish toxic myopathies from other acquired or hereditary muscle disorders. Myotoxicity resulting from direct insertion of transgenes to the muscle, an exciting new tool currently tested for treatment of muscular dystrophies, will be also discussed.

Mots clés: MYOPATHY

Marinos C Dalakas. TOXIC AND DRUG INDUCED MYOPATHIES. Journal of Neurology, Neurosurgery and Psychiatry, 2009, 80 (8), pp.832. ⟨10.1136/jnnp.2008.168294⟩. ⟨hal-00552747⟩