VitalsCentral

Simvastatin

Zocor | FloLipid

FDA ApprovedCardiovascular AgentsStatins
Half-life: 2-3 hours (active metabolite)Pregnancy: Category X

Overview

Simvastatin is an HMG-CoA reductase inhibitor (statin) used to lower LDL cholesterol and triglycerides and to reduce the risk of cardiovascular events.

Indications

  • Primary hyperlipidemia
  • Mixed dyslipidemia
  • Prevention of cardiovascular events
  • Homozygous familial hypercholesterolemia

Contraindications

  • Active liver disease
  • Pregnancy and breastfeeding
  • Concomitant use of strong CYP3A4 inhibitors

Classification

Cardiovascular AgentsStatinsCardiovascular System

Mechanism of Action

Competitively inhibits HMG-CoA reductase, the rate-limiting enzyme in hepatic cholesterol synthesis, upregulating LDL receptors and increasing clearance of LDL from the blood.

Pharmacodynamics

Lowers total and LDL cholesterol and triglycerides and modestly raises HDL cholesterol. Simvastatin is a prodrug that is hydrolyzed to its active beta-hydroxy acid form.

Pharmacokinetics

Absorption
Well absorbed but extensive first-pass hepatic extraction limits systemic availability.
Distribution
Highly protein bound; extensive uptake by the liver.
Metabolism
Extensively metabolized by CYP3A4 to active and inactive metabolites.
Excretion
Primarily excreted in feces via bile; minor renal elimination.
Half-life
2-3 hours (active metabolite)
Bioavailability
Less than 5% (high first-pass metabolism)
Protein Binding
Approximately 95%

Dosage

Typical dosage: 10-40 mg once daily in the evening

Available Forms

  • Tablet
  • Oral suspension

Side Effects

Common

  • Headache
  • Myalgia
  • Constipation
  • Elevated liver enzymes

Serious

  • Rhabdomyolysis
  • Myopathy
  • Hepatotoxicity

Rare

  • Immune-mediated necrotizing myopathy

Drug Interactions

Clarithromycinmajor

Strong CYP3A4 inhibition markedly increases simvastatin levels and the risk of myopathy and rhabdomyolysis.

Amlodipinemoderate

Increases simvastatin exposure; the simvastatin dose should not exceed 20 mg daily.

Warnings

Pregnancy

Category X

Toxicity

Overdose is generally well tolerated; the main concern is dose-related myopathy and hepatotoxicity.

Overdose

No specific antidote. Provide supportive care and monitor liver enzymes and creatine kinase.

References

Looking for patient-friendly information? Visit RemedyDoor for easy-to-read guides about this medication.