1. The destruction of skeletal muscle cells. Often the result of electrical injury, alcoholism, injury (or laying in one position for an extended period of time), drug side effects or toxins.
2. A condition in which skeletal muscle cells break down, releasing myoglobin (the oxygen-carrying pigment in muscle) together with enzymes and electrolytes from inside the muscle cells.

The risks with rhabdomyolysis include muscle breakdown and kidney failure since myoglobin is toxic to the kidneys.

Rhabdomyolysis can occur from extensive muscle damage as, for example, from a crushing injury or an electrical shock. Drugs or toxins, particularly some of the cholesterol lowering medications such as cerivastatin (Baycol), may cause this disorder. Underlying diseases such as systemic lupus erythematosus can also lead to rhabdomyolysis. It is a common complication of major burns.