Zocor (Simvastatin) 5–40 mg Tablets: Prescription Evening-Dosed Statin for High LDL, Elevated Triglycerides, and Cardiovascular Risk Reduction

Information last reviewed: May 2026 — for educational purposes only.

Simvastatin, branded as Zocor, is a prescription HMG-CoA reductase inhibitor (statin) used to lower LDL cholesterol, raise HDL, and reduce triglycerides as part of comprehensive cardiovascular risk management. It is also a component of Vytorin (simvastatin + ezetimibe) and formerly Simcor (simvastatin + niacin). Simvastatin has a relatively short half-life and should be taken in the evening to align with peak nocturnal cholesterol synthesis, maximising efficacy. This distinguishes it from atorvastatin and rosuvastatin, which have longer half-lives permitting anytime dosing.

What Is Zocor (Simvastatin) Used For?

• Hypercholesterolaemia — reduces LDL by ~20–40% depending on dose
• Mixed dyslipidaemia — reduces triglycerides and raises HDL
• Cardiovascular event reduction — myocardial infarction, stroke, coronary revascularisation in high-risk patients (4S trial, HPS trial)
• Heterozygous and homozygous familial hypercholesterolaemia

Critical CYP3A4 Drug Interactions

Simvastatin is extensively metabolised by CYP3A4. Multiple interactions are clinically significant:

• Grapefruit juice — substantially raises simvastatin plasma levels; avoid
• Clarithromycin, erythromycin, telithromycin, itraconazole, ketoconazole, posaconazole, voriconazole — CONTRAINDICATED; risk of severe myopathy or rhabdomyolysis
• HIV protease inhibitors (nelfinavir, saquinavir, lopinavir/ritonavir, etc.) — CONTRAINDICATED
• Fusidic acid — CONTRAINDICATED
• Cyclosporine, danazol — CONTRAINDICATED
• Amiodarone — simvastatin dose must not exceed 20 mg/day
• Amlodipine, ranolazine — simvastatin dose must not exceed 20 mg/day
• Diltiazem, verapamil — simvastatin dose must not exceed 10 mg/day
• Niacin ≥1 g/day combined with simvastatin raises myopathy risk, particularly in Chinese patients

FDA 80 mg Dose Restriction

In 2011, the FDA restricted the simvastatin 80 mg dose due to an unacceptably high risk of myopathy and rhabdomyolysis. Simvastatin 80 mg should only be continued in patients who have been taking it for 12 months or more without evidence of myopathy. New patients should not be started on simvastatin 80 mg; in such cases, an alternative high-intensity statin (atorvastatin 40–80 mg or rosuvastatin 20–40 mg) should be used instead.

Strengths and Dosing

• 5 mg tablet — lowest initiation dose, used in renally impaired patients or those at myopathy risk
• 10 mg tablet — low-intensity therapy; maximum dose when co-prescribing diltiazem or verapamil
• 20 mg tablet — maximum dose with amiodarone or amlodipine
• 40 mg tablet — moderate-to-high intensity; most commonly used dose
• 80 mg tablet — FDA-restricted; continuation only in established stable patients; do not initiate new patients
• Dosing time: Take in the evening (bedtime) to maximise LDL-lowering efficacy
• Can be taken with or without food

Price of Generic Simvastatin

Generic simvastatin is among the most affordable statins available. With a GoodRx or similar coupon, a 30-day supply of simvastatin 20 mg or 40 mg typically costs $4–$12 at major US pharmacies. Brand-name Zocor is rarely dispensed.

Frequently Asked Questions

Why must simvastatin be taken in the evening?

Cholesterol synthesis in the liver follows a circadian rhythm, peaking during night-time hours. Simvastatin has a relatively short half-life (~2 hours for the active acid form), so taking it in the evening ensures the drug's peak inhibitory effect coincides with maximum cholesterol production. Evening dosing typically provides 10–20% greater LDL reduction compared to morning dosing. Unlike simvastatin, atorvastatin (half-life ~14h) and rosuvastatin (half-life ~19h) can be taken at any time.

What are the signs of simvastatin-related muscle problems?

Myalgia (muscle pain or weakness without CK elevation) is the most common muscle-related complaint. Myositis involves muscle inflammation with elevated CK. Rhabdomyolysis — the most serious form — involves massive muscle breakdown with markedly elevated CK, brown urine (myoglobinuria), and may cause acute kidney injury. Report unexplained muscle pain, weakness, or dark urine to your doctor immediately. Risk is substantially higher at simvastatin 80 mg and with interacting drugs or conditions that raise simvastatin plasma levels.

Can simvastatin be used during pregnancy?

No. Simvastatin is contraindicated during pregnancy and breastfeeding. Cholesterol biosynthesis is essential for foetal development, and statins may cause foetal harm. Statins should be discontinued before attempting conception and should not be used during pregnancy or while breastfeeding. Women of childbearing potential should be counselled on adequate contraception.

← Back to Cholesterol Medications