The rates of adverse events resulting from different doses of atorvastatin in routine clinical practice are also uncertain and would need to be considered in combination with effectiveness in assessing the relative costs and benefits of different doses of atorvastatin. Appendix A: Grouping of statins For the purpose of this guideline, statins are grouped into 3 different intensity categories according to the percentage reduction in low-density lipoprotein cholesterol: a 20% to 30% reduction is low intensity a 31% to 40% reduction is medium intensity a reduction of more than 40% is high intensity. This grouping was agreed by guideline development group consensus, informed by analyses in the literature. See the full guideline for a discussion of this grouping. Grouping of statins used in this guideline: reduction in low-density lipoprotein (LDL) cholesterol by daily dose Fluvastatin: 20 mg/day, 21% reduction 40 mg/day, 27% reduction 80 mg/day, 33% reduction Pravastatin: 10 mg/day, 20% reduction 20 mg/day, 24% reduction 40 mg/day, 29% reduction Simvastatin: 10 mg/day, 27% reduction 20 mg/day, 32% reduction 40 mg/day, 37% reduction 80 mg/day, 42% reduction Atorvastatin: 10 mg/day, 37% reduction 20 mg/day, 43% reduction 40 mg/day, 49% reduction 80 mg/day, 55% reduction Rosuvastatin: 5 mg/day, 38% reduction 10 mg/day, 43% reduction 20 mg/day, 48% reduction 40 mg/day, 53% reduction MHRA advice: there is an increased risk of myopathy associated with high dose (80 mg) simvastatin. The 80 mg dose should be considered only in patients with severe hypercholesterolaemia and high risk of cardiovascular complications who have not achieved their treatment goals on lower doses, when the benefits are expected to outweigh the potential risks. This information is from Law MR, Wald NJ, Rudnicka AR (2003) Quantifying effect of statins on low-density lipoprotein cholesterol, ischaemic heart disease, and stroke: systematic review and meta-analysis. BMJ 326: 1423. 