Statin dose equivalency

Convert between statins on the basis of approximately equivalent LDL-lowering effect.

What is this for?

Statins differ substantially in potency per milligram. This table gives approximately LDL-equivalent daily doses, which is useful when a formulary change or an interaction forces a switch. It is a potency comparison, not the intensity classification used in guidelines.

How to use it

Select the current statin and enter the daily dose.
Select the statin you are switching to.
Cross-check the resulting dose against the guideline intensity category, and against the maximum approved dose for that agent.

Worked example

A patient on simvastatin 40 mg is switching to atorvastatin because of a drug interaction. What is the approximately equivalent dose?

Answer: 40 mg × (10 ÷ 20) = 20 mg of atorvastatin. Note that atorvastatin 20 mg is moderate-intensity therapy; if the patient requires high-intensity therapy, 40–80 mg would be needed regardless of the equivalency.

Clinical pearls & pitfalls

Equivalent potency is not equivalent evidence. Atorvastatin and rosuvastatin have the outcome data supporting high-intensity therapy; substituting an equipotent dose of a different agent does not automatically carry that evidence across.
Simvastatin 80 mg is not recommended because of a substantially increased myopathy risk, and the FDA restricted its use. Never convert to simvastatin 80 mg.
Doubling a statin dose gains only about 6% additional LDL reduction — the "rule of 6". This is why adding ezetimibe often achieves more than escalating the statin.
Interactions differ markedly across the class. Simvastatin and lovastatin are CYP3A4 substrates with many contraindicated combinations; pravastatin, rosuvastatin, and pitavastatin have far fewer.
Check the maximum approved dose of the target agent. An equivalency calculation can return a dose above the licensed maximum, particularly when converting from a high-potency agent.

Assumptions & limitations

Approximate LDL-equivalence only. Individual response varies widely, and the equivalence does not extend to triglyceride or HDL effects.
Does not reflect outcome-trial evidence, which is agent- and dose-specific.
Does not account for drug interactions, renal dosing caps, or the specific contraindications that differ across the class.
Does not apply to combination products or to non-statin lipid-lowering agents.

References

Grundy SM, et al. 2018 AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA guideline on the management of blood cholesterol. Circulation. 2019;139(25):e1082-e1143.
Weng TC, et al. A systematic review and meta-analysis on the therapeutic equivalence of statins. J Clin Pharm Ther. 2010;35(2):139-151.
US Food and Drug Administration. FDA Drug Safety Communication: new restrictions, contraindications, and dose limitations for Zocor (simvastatin).