What is the dose of atorvastatin (Lipitor) equivalent to rosuvastatin (Crestor) 20mg?

Atorvastatin Dose Equivalent to Rosuvastatin 20mg

Atorvastatin 40-80mg is the equivalent dose to rosuvastatin 20mg, with atorvastatin 40mg being the most commonly recommended initial equivalent dose for switching between these high-intensity statins. 1, 2

Statin Intensity Classification

Both rosuvastatin 20mg and atorvastatin 40-80mg are classified as high-intensity statin therapy, defined as achieving ≥50% reduction in LDL cholesterol from baseline. 1, 2

• Rosuvastatin 20-40mg achieves approximately 50-55% LDL-C reduction 2, 3
• Atorvastatin 40-80mg achieves approximately 50-55% LDL-C reduction 1, 2
• Both doses are explicitly listed as high-intensity options in American College of Cardiology/American Heart Association and American Diabetes Association guidelines 1, 2

Evidence-Based Dose Equivalence

The most appropriate equivalent dose is atorvastatin 40mg when switching from rosuvastatin 20mg. 2

Comparative Potency Data

• Rosuvastatin is approximately 3-3.5 times more potent than atorvastatin on a milligram-per-milligram basis 3, 4
• Rosuvastatin 20mg produces approximately 50% LDL-C reduction, requiring atorvastatin 70mg to achieve equivalent LDL-C lowering in head-to-head trials 4
• However, guideline-based statin intensity classification groups rosuvastatin 20mg with atorvastatin 40-80mg as equivalent high-intensity options 1, 2

Clinical Trial Evidence

Direct comparative studies demonstrate:

• Rosuvastatin 20mg reduced LDL-C by 46.6-50% versus atorvastatin 20mg at 38.2-44% 5, 4
• At any given milligram dose, rosuvastatin yields an 8.4% greater decrease in LDL cholesterol compared to atorvastatin 5
• More patients achieved LDL-C targets with rosuvastatin 20mg than atorvastatin 20mg (79% vs 64%) 6

Practical Conversion Algorithm

When switching from rosuvastatin 20mg:

1. Start with atorvastatin 40mg as the standard equivalent dose to maintain high-intensity therapy 2, 3
2. Monitor lipid panel 4-12 weeks after conversion to verify ≥50% LDL-C reduction from baseline is maintained 2, 3
3. Titrate to atorvastatin 80mg if LDL-C goal (<70 mg/dL for high-risk patients) is not achieved 1, 2
4. Consider patient-specific factors including renal function, drug interactions (particularly CYP3A4 substrates), and prior statin tolerance 2, 3

Important Safety Considerations

Comparative Tolerability

• Atorvastatin has higher rates of adverse drug reactions compared to rosuvastatin at high-intensity doses (4.59% vs 2.91%) 7
• Atorvastatin shows increased risk of abnormal liver transaminases (3.99% vs 1.39%) and statin-associated muscle symptoms (1.14% vs 0.5%) compared to rosuvastatin 7
• Patients on rosuvastatin remained on therapy 2.5 times longer before developing adverse reactions 7

Drug Interactions

• Rosuvastatin has fewer drug interactions than atorvastatin, as atorvastatin is metabolized by CYP3A4 3
• Consider this when patients are on medications that interact with CYP3A4 (e.g., certain calcium channel blockers, azole antifungals, macrolide antibiotics) 3

Renal Considerations

• For patients with severe renal impairment (CrCl <30 mL/min), rosuvastatin should not exceed 10mg daily 2
• Atorvastatin generally requires no dose adjustment for renal impairment alone 2

Common Pitfalls to Avoid

• Do not assume 1:1 dose equivalence between atorvastatin and rosuvastatin (e.g., switching rosuvastatin 20mg to atorvastatin 20mg would represent significant de-escalation from high-intensity to moderate-intensity therapy) 1, 3
• Do not use atorvastatin 10-20mg as equivalent to rosuvastatin 20mg, as this is only moderate-intensity therapy 1, 3
• Do not fail to recheck lipid panel 4-12 weeks after conversion, as individual patient responses vary 2, 3
• Do not overlook drug interactions when switching, particularly with CYP3A4-metabolized medications 3