Background: Atorvastatin is a widely used statin, of which there are two available polymorphs: crystalline (original) and amorphous (generic). Pharmacological studies showed the similarity between both forms. However, the lipid-lowering effectiveness of the amorphous form was still uncertain.

Objective: To compare the effectiveness of crystalline and amorphous form of atorvastatin.

Materials and Methods: The authors conducted an observational cross-sectional analytic study by retrospectively collecting data from January 1, 2016 to December 31, 2017 of the patients at Queen Sirikit Heart Center of the Northeast where the original regimen of crystalline atorvastatin had been replaced by the amorphous atorvastatin at the same dose. Patients must have been prescribed each form of atorvastatin for at least six weeks. The lipid profiles taken at the closest to the switching point (before and after) were used. The primary outcome was changes in low-density lipoprotein (LDL) levels. The secondary outcomes were changes in total cholesterol (TC), triglyceride (TG), and high-density lipoprotein (HDL) levels, as well as a comparison of LDL levels in patients whose tablets were split.

Results: Eight hundred twenty-five patients were included in the present study. The mean age was 63.7±9.9 years. Five hundred sixty-eight patients (68.8%) were male, and 736 (89.2%) were treated as secondary prevention. The mean LDL levels during crystalline and amorphous atorvastatin use were 92.4±39.0 and 91.8±41.0 mg/dL, respectively (mean difference –0.6; 95% confidence interval [CI], –2.2 to 1.0; p=0.460). The mean TC, TG, and HDL levels during crystalline and amorphous form use were 153.1±43.3 and 152.0±48.6 mg/dL (p=0.400), 153.4±129.0 and 155.0±148.3 (p=0.740), 43.6±11.9, and 44.4±12.0 (p=0.004), respectively. Among the patients who had tablet splitting, the mean LDL levels during crystalline and amorphous atorvastatin use were 89.2±28.3 and 91.0±30.8 mg/dL, respectively (p=0.279). Side effects were recorded in nine patients, one of which was rhabdomyolysis.

Conclusion: The effectiveness of amorphous atorvastatin at lowering lipids was comparable to that of atorvastatin in its crystalline form, and patients were generally able to tolerate amorphous atorvastatin.

Keywords: Atorvastatin, Crystalline, Amorphous, Lipid-lowering, Low-density lipoprotein

DOI: doi.org/10.35755/jmedassocthai.2020.09.10321

Received 17 June 2019 | Revised 31 October 2019 | Accepted 1 November 2019