What is the equivalent dose of atorvastatin (Lipitor) for a patient taking rosuvastatin (Crestor) 20mg?

Statin Equivalence: Rosuvastatin 20mg to Atorvastatin

The equivalent dose of atorvastatin for a patient taking rosuvastatin 20mg is approximately 40-70mg of atorvastatin, with most guidelines suggesting atorvastatin 40mg as the closest equivalent dose.

Statin Intensity Classification

• Rosuvastatin 20mg is classified as high-intensity statin therapy, defined as treatment that lowers LDL cholesterol by ≥50% from baseline according to the American College of Cardiology/American Heart Association guidelines 1, 2
• High-intensity statin therapy includes rosuvastatin 20-40mg and atorvastatin 40-80mg 1, 2
• Moderate-intensity statin therapy (30-50% LDL-C reduction) includes rosuvastatin 5-10mg and atorvastatin 10-20mg 1, 3

Specific Dose Equivalence

• According to the VOYAGER meta-analysis, rosuvastatin 20mg reduces LDL-C by approximately 50% and non-HDL-C by 45% 4
• To achieve equivalent LDL-C reduction to rosuvastatin 20mg, approximately atorvastatin 70mg would be required 4
• To achieve equivalent non-HDL-C reduction to rosuvastatin 20mg, approximately atorvastatin 62mg would be required 4
• Since atorvastatin is typically prescribed in 10mg, 20mg, 40mg, or 80mg doses, atorvastatin 40mg would be the closest standard dose for most patients, with atorvastatin 80mg being considered for those requiring maximum lipid-lowering effect 3, 4

Comparative Potency

• Rosuvastatin is approximately 3-3.5 times more potent than atorvastatin on a milligram-to-milligram basis for reducing LDL-C and non-HDL-C 4
• In clinical practice, this means rosuvastatin 20mg would be roughly equivalent to atorvastatin 60-70mg 4
• Since atorvastatin 60-70mg is not a standard dose, clinicians typically use atorvastatin 40mg or 80mg as the practical equivalent 3

Clinical Considerations When Switching

• When converting from rosuvastatin 20mg to atorvastatin, monitor lipid levels 4-12 weeks after conversion to ensure equivalent efficacy 3
• Consider patient-specific factors such as age, renal function, and concomitant medications when converting between statins 3
• For patients with renal impairment (CrCl <30 mL/min), rosuvastatin dosing should be adjusted, while atorvastatin generally requires no dose adjustment for renal impairment alone 3

Practical Application

• For most patients switching from rosuvastatin 20mg, atorvastatin 40mg would be the initial equivalent dose 1, 4
• For patients requiring maximum LDL-C reduction (≥50%), consider atorvastatin 80mg 1, 4
• For patients with concerns about tolerability, starting with atorvastatin 20mg and titrating up based on lipid response and side effects may be reasonable 3

Common Pitfalls

• Failing to recognize the higher potency of rosuvastatin compared to atorvastatin on a milligram-to-milligram basis 4
• Not monitoring lipid levels after conversion to ensure therapeutic equivalence 3
• Overlooking patient-specific factors that might affect statin metabolism or tolerability 3