Atorvastatin Response Rate, LDL Drop by Dose Explained

What LDL Drop Should You Expect at Each Dose?

The Lipitor label pools 6-week data from adults with primary hyperlipidemia and reports mean LDL cholesterol changes of 39% at 10 mg, 43% at 20 mg, 50% at 40 mg and 60% at 80 mg, against a 4% rise on placebo [1].

In the pooled 6-week data, the additional mean LDL reduction was 4 percentage points from 10 to 20 mg, 7 from 20 to 40 mg, and 10 from 40 to 80 mg [1]. The labeled range is 10 to 80 mg once daily with a usual start of 10 to 20 mg, and patients who need more than a 45% LDL reduction may start at 40 mg [1]. The label advises checking LDL-C as early as 4 weeks after starting and adjusting the dose if needed [1].

Those percentages are averages from the pooled 6-week data, not a prediction of any one person's LDL change [1].

How Many Patients Reach Their LDL Target?

The clearest responder data come from STELLAR, a 6-week randomized, open-label comparison of 2,431 adults with LDL cholesterol of 160 to under 250 mg/dL and triglycerides under 400 mg/dL [2]. ATP III LDL goals were reached by 69% to 85% of patients on atorvastatin 10 to 80 mg, and by 82% to 89% on rosuvastatin 10 to 40 mg. Against the stricter European target of LDL below 3.0 mmol/L, the atorvastatin figures were 52% to 81%, versus 79% to 92% on rosuvastatin [2].

Across the full dose ranges, rosuvastatin reduced LDL by a mean of 8.2% more than atorvastatin, and tolerability was similar between the drugs [2]. The trial was open-label, so patients and investigators knew which drug was being taken.

Does a Bigger LDL Drop Prevent More Heart Events?

TNT randomized 10,001 patients with stable coronary heart disease and LDL under 130 mg/dL to atorvastatin 80 mg or 10 mg for a median of 4.9 years [3]. Mean on-treatment LDL was 77 mg/dL on 80 mg and 101 mg/dL on 10 mg. A first major cardiovascular event occurred in 434 patients (8.7%) on 80 mg and 548 (10.9%) on 10 mg, a hazard ratio of 0.78 (95% CI 0.69 to 0.89) and a 2.2 percentage point absolute difference. Overall mortality did not differ between the arms [3].

The wider picture comes from the Cholesterol Treatment Trialists collaboration: 26 randomized trials with about 170,000 participants [4]. Across 26 trials, each 1.0 mmol/L lower LDL cholesterol was associated with a rate ratio of 0.78 for major vascular events and 10% lower all-cause mortality [4].

Lower doses also show benefit in the right patients. In ASCOT-LLA, 10,305 hypertensive patients with at least three other risk factors took atorvastatin 10 mg or placebo; non-fatal MI plus fatal coronary heart disease occurred 100 times versus 154 times (HR 0.64, 95% CI 0.50 to 0.83) over a median 3.3 years [5]. In CARDS, 2,838 adults with type 2 diabetes and no prior cardiovascular disease had 83 major cardiovascular events on atorvastatin 10 mg versus 127 on placebo, a rate reduction of 37% [6].

What Makes One Person's Response Different From Another's?

Starting LDL. Because the dose-response results are reported as percentages, the absolute LDL-C decrease will depend on the starting LDL-C. The label reports the percentage changes, not a separate estimate of absolute reduction for each starting LDL-C [1].

Adherence. An Ontario observational study followed 31,455 elderly survivors of myocardial infarction for a median of 2.4 years [7]. Among statin users, compared with those covering at least 80% of prescription days, those covering under 40% had higher mortality: 24% versus 16% (adjusted hazard ratio 1.25, 95% CI 1.09 to 1.42) [7]. That study measured death, not LDL.

Genetics. STRENGTH randomized 509 people to atorvastatin 10 mg, simvastatin 20 mg or pravastatin 10 mg, then raised the doses to 80 mg, 80 mg and 40 mg respectively [8]. A composite of stopping for a side effect, myalgia or CK above 3 times the upper limit occurred in 99 participants. Carriers of the reduced-function SLCO1B1*5 allele made up 37% of that group versus 25% of those without the composite event, and the share with an event rose from 19% to 27% to 50% with zero, one and two copies. The study found that the risk appeared to be greatest among carriers assigned to simvastatin [8]. That trial tracked muscle side effects, not how far LDL fell.

Other drugs. Atorvastatin is a CYP3A4 substrate, and the label lists dose caps and combinations to avoid. Clarithromycin raised exposure 4.54-fold and itraconazole 3.32-fold, and both cap atorvastatin at 20 mg daily [1]. Rifampin works the other way: giving atorvastatin later rather than at the same time dropped exposure sharply (AUC ratio 0.20), so the label says to give them together [1].

What Limits the Dose People Actually Take?

Higher doses are stopped more often. In TNT, serious adverse reactions were reported in 1.8% of patients on 80 mg and 1.4% on 10 mg, and 9.9% versus 8.1% discontinued because of adverse reactions [1]. CK of 10 times the upper limit or more occurred in 0.3% versus 0.1%, and persistent transaminase elevations in 1.3% versus 0.2% [1].

Muscle symptoms feature prominently. In the label's 17 placebo-controlled trials (8,755 on atorvastatin, 7,311 on placebo, median 53 weeks), myalgia was reported by 3.5% of patients on any atorvastatin dose and 3.1% on placebo, and myalgia was the most common reason for stopping that exceeded placebo, at 0.7% [1]. A review of statin-associated muscle problems estimated that less serious muscle pain and weakness may affect 1% to 5% of patients; this estimate was not specific to atorvastatin [9]. The label lists age 65 or older, uncontrolled hypothyroidism, renal impairment, interacting drugs and higher dose as myopathy risk factors [1].

Does the Time of Day Change the Response?

No. The label says to take atorvastatin once daily at any time of day, with or without food [1]. Evening dosing produces about 30% lower peak and total exposure than morning dosing, but LDL reduction is the same at any time [1]. A study of 64 male outpatients on atorvastatin 40 mg, 32 taking it before noon and 32 after 6 p.m., found no significant difference in total cholesterol, LDL, triglycerides or HDL after 4 weeks [10].