Lovastatin

BRAND NAMES

Common brand names for lovastatin include:

• Mevacor (original brand name; first marketed form of lovastatin) 

• Altoprev (extended-release formulation) 

• Altocor (another extended-release version; less commonly used now) 

• Advicor (combination product: lovastatin + niacin)

MECHANISM OF ACTION

Lovastatin is a statin that lowers cholesterol by inhibiting the enzyme HMG-CoA reductase, which is responsible for a key step in hepatic cholesterol synthesis. 

PHARMACOKINETICS

Absorption 

Lovastatin is well absorbed orally, but it undergoes extensive first-pass metabolism in the liver, which significantly reduces its bioavailability. It is a prodrug, and the active form is generated after hepatic conversion. Absorption is enhanced when taken with food, especially with the evening meal, which is why it is usually recommended to be taken at night.

Distribution

Lovastatin is highly lipophilic and is extensively distributed into tissues, with a large volume of distribution. It is highly protein bound (>95%), mainly to plasma proteins, which limits the free circulating fraction. Its active metabolites are concentrated primarily in the liver, which is also its main site of action.

Metabolism

Lovastatin is extensively metabolized in the liver by CYP3A4 after being converted to its active form. It undergoes significant first-pass metabolism, and its levels can increase with CYP3A4 inhibitors, raising the risk of adverse effects.

Elimination

Lovastatin is primarily eliminated through biliary excretion into feces, with only a small amount excreted in urine. It has a relatively short plasma half-life, but its metabolites contribute to its prolonged lipid-lowering effect.

PHARMACODYNAMICS

Lovastatin inhibits HMG-CoA reductase, reducing hepatic cholesterol synthesis and lowering intracellular cholesterol levels. This upregulates LDL receptors on liver cells, increasing clearance of LDL from the blood and significantly reducing plasma LDL levels. It also produces modest reductions in triglycerides and slight increases in HDL, thereby improving the overall lipid profile and reducing cardiovascular risk.

ADMINISTRATION

Lovastatin is administered orally, usually in tablet form. It should be taken with food, preferably the evening meal, because cholesterol synthesis in the liver is higher at night and food improves its absorption. Extended-release formulations are also taken once daily in the evening.

DOSAGE AND STRENGTH

Lovastatin is typically started at a dose of 20 mg once daily, taken with the evening meal. Depending on response, the dose may be adjusted up to a usual maximum of 80 mg per day, given either as a single dose or divided doses. It is available in strengths such as 10 mg, 20 mg, 40 mg, and 60 mg tablets (availability may vary by country and manufacturer).

DRUG INTERACTIONS

Lovastatin interacts mainly with CYP3A4 inhibitors like macrolide antibiotics, azole antifungals, protease inhibitors, and grapefruit juice, which increase its levels and risk of muscle toxicity. It also has increased myopathy risk when combined with fibrates (especially gemfibrozil) and may enhance the effect of warfarin.

FOOD INTERACTIONS

Lovastatin should be taken with food because it improves absorption, usually with the evening meal. However, grapefruit juice should be avoided, as it inhibits CYP3A4 metabolism and can significantly increase drug levels, raising the risk of myopathy and rhabdomyolysis.

CONTRAINDICATIONS

Lovastatin is contraindicated in patients with active liver disease or unexplained persistent elevations of liver enzymes. It should not be used during pregnancy or breastfeeding due to potential harm to the fetus or infant. It is also contraindicated with strong CYP3A4 inhibitors (such as certain antifungals, macrolide antibiotics, and protease inhibitors) because of the risk of severe myopathy and rhabdomyolysis.

SIDE EFFECTS

• Headache

• Nausea

• Abdominal discomfort

• Gastrointestinal upset

• Myalgia (muscle pain)

• Myopathy

• Rhabdomyolysis (rare, severe)

• Elevated liver enzymes (hepatotoxicity)

OVER DOSE

Lovastatin overdose is managed with supportive care, as there is no specific antidote. Patients are monitored for muscle toxicity and kidney function, with treatment including drug discontinuation, hydration, and activated charcoal if given early.

TOXICITY

Lovastatin toxicity mainly involves dose-related muscle and liver effects. The most serious toxicity is myopathy and rhabdomyolysis, which can lead to acute kidney injury due to myoglobin release. Hepatotoxicity may occur, shown by elevated liver enzymes. Risk increases with high doses or interactions with CYP3A4 inhibitors, and management involves immediate discontinuation of the drug and supportive care.