Lipid-Lowering Agent (Statin) Pregnancy: Contraindicated in pregnancy and lactation; must not be used in women who are pregnant, trying to conceive or breast-feeding. Suspend treatment for the duration of pregnancy (§4.3/§4.6).

Simvastatin

Brand names: Zocor

Simvastatin is a statin (HMG-CoA reductase inhibitor) used to lower cholesterol and reduce cardiovascular risk in primary and secondary prevention.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 5–80 mg/day given orally as a single dose in the evening (usual starting dose for hypercholesterolaemia 10–20 mg/day; 20–40 mg/day if a large LDL-C reduction >45% is required or for cardiovascular prevention)

Route: Oral

Frequency: Once daily in the evening

Max: 80 mg/day — only recommended in severe hypercholesterolaemia at high cardiovascular risk who have not achieved goals on lower doses and where benefit outweighs risk

SPC (Simvastatin 10 mg film). Adjust dose at intervals of not less than 4 weeks. Homozygous familial hypercholaesterolaemia: recommended starting dose 40 mg/day in the evening (as adjunct to other lipid-lowering treatment). Dose caps with interacting drugs: with fibrates other than gemfibrozil (contraindicated) or fenofibrate — max 10 mg/day; with amiodarone, amlodipine, verapamil, diltiazem, or elbasvir/grazoprevir — max 20 mg/day; with lomitapide in HoFH — max 40 mg/day. No dosage adjustment needed in the elderly. Paediatric (children/adolescents 10–17 years, boys Tanner stage II+ and girls ≥1 year post-menarche, with heterozygous familial hypercholesterolaemia): usual starting dose 10 mg once daily in the evening; range 10–40 mg/day; maximum 40 mg/day; experience in pre-pubertal children is limited.

Dose adjustments

Renal

No modification of dosage necessary in moderate renal impairment. In severe renal impairment (creatinine clearance <30 mL/min), doses above 10 mg/day should be carefully considered and, if deemed necessary, implemented cautiously.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to simvastatin or to any of the excipients
Active liver disease or unexplained persistent elevations of serum transaminases
Pregnancy and lactation
Concomitant potent CYP3A4 inhibitors (e.g. itraconazole, ketoconazole, posaconazole, voriconazole, HIV protease inhibitors, boceprevir, telaprevir, erythromycin, clarithromycin, telithromycin, nefazodone, cobicistat-containing products)
Concomitant gemfibrozil, ciclosporin, or danazol
In HoFH, concomitant lomitapide with doses above 40 mg simvastatin

Side effects

Myopathy (including myositis) and rhabdomyolysis with or without acute renal failure (rare)
Myalgia and muscle cramps (rare)
Headache, paraesthesia, dizziness (rare)
Constipation, abdominal pain, nausea, dyspepsia (rare)
Rash, pruritus (rare)

Interactions

Potent CYP3A4 inhibitors — contraindicated (increase simvastatin exposure and myopathy/rhabdomyolysis risk)
Gemfibrozil, ciclosporin, danazol — contraindicated
Fibrates (other than gemfibrozil or fenofibrate) — limit simvastatin to max 10 mg/day
Amiodarone, amlodipine, verapamil, diltiazem, elbasvir/grazoprevir — limit simvastatin to max 20 mg/day

Clinical monograph

How it works

It competitively inhibits HMG-CoA reductase, the rate-limiting enzyme in hepatic cholesterol synthesis, upregulating LDL receptors and lowering circulating LDL-cholesterol.

Prescribing in practice

It can cause myopathy and rarely rhabdomyolysis, a risk increased by interacting drugs (including certain strong CYP3A4 inhibitors and other lipid-lowering agents) and by higher doses, so unexplained muscle pain should prompt creatine kinase measurement.
It is contraindicated in pregnancy, breastfeeding and active liver disease, and dose limits apply with several interacting medicines such as amiodarone, verapamil, diltiazem and amlodipine.
Advise patients to avoid grapefruit juice, which raises simvastatin exposure and the risk of toxicity.

Monitoring

Check liver function before and as indicated after starting, and assess lipids and any muscle symptoms with creatine kinase if myopathy is suspected.

Counselling the patient

Report promptly any unexplained muscle pain, tenderness or weakness.
Avoid grapefruit juice while taking this medicine.
Tell your clinician if you could be pregnant or are planning pregnancy, as the statin should be stopped.

Evidence & guidelines

Large randomised trials have shown simvastatin reduces major cardiovascular events, and statins are recommended by NICE for cardiovascular risk reduction.

Reference: MHRA Drug Safety Update 2012 (Simvastatin 80mg); 4S Trial (Lancet 1994); Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways