Simvastatin is used to reduce LDL-cholesterol, apolipoprotein B, and triglycerides, and to increase HDL-cholesterol in the treatment of hyperlipidaemias including hypercholesterolaemias, combined (mixed) hyperlipidaemia (type IIa or IIb hyperlipoproteinaemias), hypertriglyceridemia (type IV) and primary dysbetalipoproteinaemia (type III); as adjunct therapy in patients with homozygous familial hypercholesterolaemia who have some LDL-receptor function; used for cardiovascular risk reduction in patients with atherosclerotic cardiovascular disease or diabetes mellitus.