Lovastatin is structurally similar to the HMG, a substituent of the endogenous substrate of HMG-CoA reductase. Lovastatin is a prodrug that is activated in vivo via hydrolysis of the lactone ring. The hydrolyzed lactone ring mimics the tetrahedral intermediate produced by the reductase allowing the agent to bind with 20, 000 times greater affinity than its natural substrate. The bicyclic portion of lovastatin binds to the coenzyme A portion of the active site.
The primary cause of cardiovascular disease is atherosclerotic plaque formation. Sustained elevations of cholesterol in the blood increase the risk of cardiovascular disease. Lovastatin lowers hepatic cholesterol synthesis by competitively inhibiting HMG-CoA reductase, the enzyme that catalyzes the rate-limiting step in the cholesterol biosynthesis pathway via the mevalonic acid pathway. Decreased hepatic cholesterol levels causes increased uptake of low density lipoprotein (LDL) cholesterol and reduces cholesterol levels in the circulation. At therapeutic doses, lovastatin decreases serum LDL cholesterol by 29-32%, increases high density lipoprotein (HDL) cholesterol by 4.6-7.3%, and decrease triglyceride levels by 2-12%. HDL cholesterol is thought to confer protective effects against CV disease, whereas high LDL and triglyceride levels are associated with higher risk of disease.
Undergoes first pass hydrolysis to active metabolites _-hydroxyacid and 6'-hydroxy dervative.
LD50>1000 mg/kg (orally in mice)