What are the equivalent doses of atorvastatin (Lipitor) and simvastatin (Zocor) for a patient taking rosuvastatin (Crestor) 20mg?

Statin Dose Equivalents for Rosuvastatin 20mg

Rosuvastatin 20mg is equivalent to atorvastatin 40-80mg (most commonly 40mg) and simvastatin 80mg, though simvastatin 80mg is not recommended due to increased myopathy risk. 1

High-Intensity Statin Classification

Rosuvastatin 20mg is classified as high-intensity statin therapy, achieving ≥50% LDL-C reduction from baseline. 1 The equivalent high-intensity options are:

• Atorvastatin 40-80mg (achieves ≥50% LDL-C reduction) 1
• Simvastatin 80mg (theoretically equivalent but contraindicated - see below) 1

Specific Dose Equivalents

Atorvastatin Equivalent

• Atorvastatin 40mg is the most appropriate equivalent dose for rosuvastatin 20mg in clinical practice 1, 2
• Atorvastatin 80mg may be considered for maximal LDL-C lowering, though it carries higher adverse event risk 3
• The VOYAGER meta-analysis demonstrated that rosuvastatin 20mg (50% LDL-C reduction) requires approximately atorvastatin 70mg for equivalent LDL-C reduction, supporting atorvastatin 40-80mg as the practical equivalent 4

Simvastatin Equivalent

• Simvastatin 80mg is NOT recommended despite being theoretically equivalent 1
• The FDA specifically warns against initiating or titrating to simvastatin 80mg due to increased myopathy and rhabdomyolysis risk 1
• Simvastatin 20-40mg is classified only as moderate-intensity therapy (30-49% LDL-C reduction), making it inadequate as an equivalent to rosuvastatin 20mg 1
• The VOYAGER analysis showed that simvastatin 80mg cannot achieve the 50% LDL-C reduction produced by rosuvastatin 20mg 4

Practical Conversion Algorithm

When switching from rosuvastatin 20mg:

1. First-line choice: Atorvastatin 40mg 1, 2

   • Maintains high-intensity therapy status
   • Well-tolerated at this dose
   • FDA-approved without special restrictions

2. Alternative: Atorvastatin 80mg 1

   • Consider only if maximal LDL-C lowering needed
   • Monitor closely for adverse effects (higher ADR rate: 4.59% vs 2.91% with rosuvastatin) 3
   • Increased risk of abnormal liver transaminases (3.99% vs 1.39%) and muscle symptoms (1.14% vs 0.5%) 3

3. Avoid simvastatin as equivalent 1

   • Maximum safe dose (40mg) provides only moderate-intensity therapy
   • 80mg dose contraindicated by FDA

Critical Monitoring After Conversion

• Check lipid panel 4-12 weeks after conversion to verify ≥50% LDL-C reduction is maintained 2
• Monitor for muscle symptoms, particularly with atorvastatin 80mg 3
• Check liver transaminases if clinically indicated 3

Important Caveats

• Renal impairment: In patients with CrCl <30 mL/min, atorvastatin is preferred over rosuvastatin as it requires no dose adjustment, whereas rosuvastatin should not exceed 10mg daily 2
• Drug interactions: Both atorvastatin and simvastatin are metabolized via CYP3A4; limit simvastatin to 20mg (not 40mg) when used with amiodarone, but atorvastatin requires no dose adjustment with amiodarone 1
• Individual response varies: The percentage LDL-C reductions are population estimates; actual patient response should be verified with follow-up lipid testing 1