Adjunct to diet when response to diet & other non-pharmacological treatments (eg, exercise, wt reduction) is inadequate in adults, adolescents & childn ≥6 yr w/ primary hypercholesterolaemia (type IIa including heterozygous familial hypercholesterolaemia) or mixed dyslipidaemia (type IIb). Adjunct to diet & other lipid-lowering treatments (eg, LDL apheresis) or if such treatments are not appropriate in adults, adolescents & childn ≥6 yr w/ homozygous familial hypercholesterolaemia. Decrease elevated total cholesterol (total-C), LDL-cholesterol (LDL-C) & triglycerides (TG) & increase high density lipoprotein cholesterol (HDL-C) in adults w/ primary hypercholesterolemia (heterozygous familial & non-familial) or mixed dyslipidemia (Fredrickson types IIa & IIb). Decrease Apo B, non-HDL-C, VLDL-C, VLDL-TG, LDL-C/HDL-C & Apo B/Apo A-I ratios & increase Apo A-I in adults. Isolated hypertriglyceridemia (Fredrickson type IV hyperlipidemia). Primary dysbetalipoproteinemia (Fredrickson type III hyperlipoproteinemia). Decrease total-C & LDL-C in patients w/ homozygous familial hypercholesterolaemia as adjunct to other lipid-lowering treatments or alone. Slow progression of atherosclerosis to decrease total-C & LDL-C. Decrease total-C, LDL-C & Apo B levels in childn & adolescents 6-17 yr (boys ≥ Tanner Stage II & girls who are at least 1 yr post-menarche) w/ heterozygous familial hypercholesterolaemia. Decrease risk of stroke, MI & arterial revascularization procedures in individuals w/o clinically evident CHD but w/ increased risk of CV disease.