When administered to juvenile rats (postnatal days [PND] 4 through 80 at 5 to 45 mg/kg/day), no drug related changes were observed at 5 mg/kg/day. At 15 and 45 mg/kg/day, altered body-weight gain was observed during the dosing and 52-day recovery periods as well as slight thinning of the corpus callosum at the end of the recovery period. This finding was not evident in rats examined at the completion of the dosing period and was not associated with any inflammatory or degenerative changes in the brain. The biological relevance of the corpus callosum finding is uncertain due to the absence of any other microscopic changes in the brain or peripheral nervous tissue and because it occurred at the end of the recovery period. Neurobehavioral changes (enhanced acoustic startle responses and increased errors in water-maze learning) combined with evidence of generalized toxicity were noted at 45 mg/kg/day during the later part of the recovery period. Serum Pravastatin levels at 15 mg/kg/day are approximately ≥ 1 times (AUC) the maximum pediatric dose of 40 mg. No thinning of the corpus callosum was observed in rats dosed with Pravastatin (≥ 250 mg/kg/day) beginning PND 35 for 3 months suggesting increased sensitivity in younger rats. PND 35 in a rat is approximately equivalent to an 8- to 12-year-old human child. Juvenile male rats given 90 times (AUC) the 40 mg dose had decreased fertility (20%) with sperm abnormalities compared to controls.
Myopathies in systemic disease results from several different disease processes including endocrine, inflammatory, paraneoplastic, infectious, drug- and toxin-induced, critical illness myopathy, metabolic, collagen related,  and myopathies with other systemic disorders. Patients with systemic myopathies often present acutely or sub acutely. On the other hand, familial myopathies or dystrophies generally present in a chronic fashion with exceptions of metabolic myopathies where symptoms on occasion can be precipitated acutely. Most of the inflammatory myopathies can have a chance association with malignant lesions; the incidence appears to be specifically increased only in patients with dermatomyositis. 
For patients who present with rhabdomyolysis, treatment is aimed at preventing kidney failure in the acute setting. Vigorous hydration with close monitoring of kidney function and electrolytes are paramount. In patients with an underlying metabolic myopathy, education about following a more moderate exercise program and avoiding intense exercise and fasting is necessary in preventing recurrent episodes. Measures that have been suggested to be helpful include sucrose loading before exercise in some glycogen storage disorders and a low-fat, high-carbohydrate diet in patients with lipid storage disorders.