Pharmacologic lipid-lowering interventions should be monitored periodically to assess efficacy and safety parameters. Statins are usually well-tolerated drugs and major side effects include increased serum liver and muscle enzymes (AST, ALT, CK). Treatment should be stopped or diminished in case of significant increase of AST or ALT (> 3x ULN), or CK (> 10x ULN). Other lipid lowering agents may also produce hepatotoxicity or myositis, especially in association with statins (fibrates and nicotinic acid) or in presence of metabolic abnormalities (thyroid, liver or renal disorders). Nicotinic acid can also increase glucose and uric acid plasma levels. Laboratory tests might be performed prior to hypolipidemic drug treatment and should be repeated every three months during the first year and then at 6-mo intervals. Shorter intervals should be recommended in individual cases.

Liver disease following the use of hypolipidemic drugs has been reported as a cellular damage (increases in AST or ALT enzymes) without cholestatic alterations (bilirubin and or alkaline phosphatase increases). Six mechanisms were proposed for hepatotoxicity : 1. High energy reactions on P450 cytochrome impairing calcium homestasis with rupture of intracellular fibrils and hepatocyte lysis. 2. Impairment of transporter proteins related to the bile acids flux (mechanism proposed for fibrate liver toxicity). 3. Immune reactions due to the formation of metabolites linked to enzymes following liver metabolism of hypolipidemic drugs. 4. Hepatotoxicity by T cells with additional inflammation mediated by neutrophils. 5. Apoptosis mediated by TNF and Fas (immune mediated). 6. Oxidative stress due to damage of intracellular organelles. In addition, advanced age, alcohol in excess, high doses of hypolipidemic drugs, interaction with other drugs, and previous active liver disease might increase liver toxicity.