ClinCalc Pro
Menu
Calculators Drugs Pathways AI Dx Donate Get the App
Statin — HMG-CoA Reductase Inhibitor Pregnancy: Contraindicated in pregnancy

Simvastatin

Brand names: Zocor

Adult dose

Dose: 10-40 mg once daily
Route: Oral
Frequency: Once daily (evening)
Max: 40 mg/day (80 mg no longer routinely used due to rhabdomyolysis risk — MHRA 2012)
Evening administration optimises efficacy (cholesterol synthesis peaks at night)

Paediatric dose

Dose: Seek specialist opinion N/A/kg
Route: Oral
Frequency: Seek specialist opinion
Max: Seek specialist opinion
Seek specialist opinion

Dose adjustments

Renal

Start at 5-10 mg if eGFR under 30; increase cautiously with monitoring

Hepatic

Contraindicated in active liver disease

Paediatric weight-based calculator

Seek specialist opinion

Clinical pearls

  • MHRA 2012 safety alert: Simvastatin 80 mg associated with increased myopathy risk — 80 mg should only be used in patients already tolerating it long-term; new patients should not be started on 80 mg
  • Multiple dose-ceiling interactions in elderly (amiodarone, amlodipine, verapamil) — atorvastatin is often a safer choice due to fewer CYP3A4 interaction-related dose limits
  • In frail elderly over 85 or those with limited life expectancy: consider deprescribing — absolute benefit is small and pill burden significant (STOPP criteria v3)
  • Evening dosing is important for simvastatin (unlike atorvastatin, which can be taken at any time)
  • HEART PROTECTION STUDY: demonstrated benefit in secondary prevention regardless of baseline cholesterol level

Contraindications

  • Active liver disease
  • Pregnancy and breastfeeding
  • Concurrent use of strong CYP3A4 inhibitors (itraconazole, ketoconazole, clarithromycin, ciclosporin)

Side effects

  • Myalgia (most common)
  • Rhabdomyolysis (rare — risk increased at 80 mg or with interacting drugs)
  • Elevated transaminases
  • New-onset diabetes
  • Headache

Interactions

  • Amiodarone (limit simvastatin to 20 mg/day — myopathy risk)
  • Amlodipine (limit to 20 mg/day)
  • Verapamil / diltiazem (limit to 10 mg/day)
  • Clarithromycin / itraconazole (contraindicated — CYP3A4 inhibition causing myopathy/rhabdomyolysis)
  • Colchicine (myopathy risk)
  • Warfarin (modest INR increase)

Monitoring

  • Lipid profile
  • LFTs (baseline, 3 months)
  • CK (if muscle symptoms)
  • INR if on warfarin

Reference: BNFc; BNF 90; MHRA Drug Safety Update 2012 (simvastatin 80 mg); NICE NG238; Heart Protection Study; STOPP/START v3. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

Calculators
Drugs
Pathways