Simvastatin

HMG-CoA Reductase Inhibitor·Cardiovascular - Lipid Lowering

Hypercholesterolaemia, mixed dyslipidemia, coronary heart disease secondary prevention (4S trial), diabetes with cardiovascular risk

PBSSTATINZocor, Lipex, Simvar5 mg tabletS4+1

Max Dose

40 mg/day (ON)

Half-life

2-3 h

Myopathy

HIGH CYP3A4

Hepatic

LFTs REQ

Rapid Summary

Overview

Foundational HMG-CoA reductase inhibitor (statin). Landmark trial proof in secondary prevention (4S trial). Short half-life requiring evening administration and highest CYP3A4 drug-interaction liability among statins.

Maximum Dose

Max 40 mg/day taken at night. The 80 mg dose is restricted due to heightened rhabdomyolysis risk.

Clinical Focus

Must be taken in the evening/night. Avoid strong CYP3A4 inhibitors (Clarithromycin, Itraconazole, Grapefruit juice) which precipitate life-threatening rhabdomyolysis.

Bottom Line

Simvastatin is an effective lipid-lowering agent with robust cardiovascular trial evidence, but its high CYP3A4 interaction sensitivity and evening-dosing requirement make it more interaction-prone than atorvastatin or rosuvastatin.

Formulation & Access

Brand Names

Zocor, Lipex, Simvar

Oral Routes

Tablets (5 mg, 10 mg, 20 mg, 40 mg, 80 mg).

Prescribing & PBS

Unrestricted General Benefit (S4).

Indications & Use

Primary

PBSTGA

Hypercholesterolaemia, mixed dyslipidemia, coronary heart disease secondary prevention (4S trial), diabetes with cardiovascular risk.

Clinical Place

Established statin for primary and secondary cardiovascular risk reduction. Often switched to Atorvastatin or Rosuvastatin for greater potency or fewer CYP3A4 interactions.

Quick reference

Class & Role

HMG-CoA Reductase Inhibitor — Lipid-lowering statin for primary and secondary CV prevention.

Route / Formulation

PO tablets: 5 mg, 10 mg, 20 mg, 40 mg, 80 mg (Zocor, Lipex, Simvar)

Usual Dose & Max

PO 10-20 mg ON (evening). Max 40 mg/day (80 mg dose restricted due to myopathy risk).

Key Indication Doses

Primary: 10-20 mg ON. High risk/CAD: 20-40 mg ON. Renal: 5-10 mg ON if eGFR < 30.

Best Uses

Avoid / Cautions

Active liver disease. Pregnancy Category D (Absolute contraindication). Strong CYP3A4 inhibitors (Contraindicated).

Key Risks

Musculoskeletal: Myalgia, myopathy, rhabdomyolysis (CRITICAL with CYP3A4 inhibitors). Hepatic: Transaminitis.

Key Interactions

Strong CYP3A4 inhibitors (Clarithromycin, Itraconazole, Grapefruit juice) cause rhabdomyolysis. Gemfibrozil contraindicated. Cap at 20 mg with Amlodipine/Diltiazem.

Monitoring

Baseline lipids and LFTs. Prompt CK if muscle pain or dark urine occurs.

Clinical Pearl

Must be taken in the evening due to short 2-3h half-life. Never combine with Clarithromycin (suspend statin during course).

Access

Zocor, Lipex, Simvar5 mg tablet

Brand: Zocor, Lipex, Simvar
Formulation: Tablets (5 mg, 10 mg, 20 mg, 40 mg, 80 mg)