Incidence of skeletal muscle disorders after statins' treatment: consequences in clinical and EMG picture.

OBJECTIVES: The goal of this clinical trial was to determine the incidence of undesirable side effects, and to ascertain any occurrence of genetic polymorphisms.

MATERIAL AND METHODS: Clinically, we looked for manifestations of a benign myositis and of serious rhabdomyolysis. We observed a group 198 patients treated with statins, primarially fluvastatin and rosuvastatin. There were 126 (mean age = 58.3 ± 4.1; male 91, mean age = 57.4 ± 5.9; female 35, mean age = 60.5 ± 6.5) patients in a subgroup where we administered rosuvastatin. Undesirable muscular signs and symptoms were present in 32 patients (25.39%). In 11 (8.73% of the total 126) CK level increased maximally to 4 times ULN, in 6 (4.7%) statins were excluded because of very intense subjective suffering. CK levels 2-5 times ULN were present in 9 (7.14%). CK blood levels over 10 times ULN or higher indicated statins exclusion in 2 (1.58%). Increased levels of the further muscular enzyme AST by 5 times ULN were present in 16 (12.69%), up to 10 times ULN in 2 (1.58%), and over 10 times ULN also in 2 (1.58%).

RESULTS: We observed rhabdomyolysis in 6 patients (3.03% of the total 198 patients group) using other types of statins (three of them undergo chronic hemodialysis). In this group we performed molecular-genetic analysis of the following proteins relating to statin myopathy: SLCO1B1(388AA/AG-521TT) - (discovered polymorphism in 1 patient), further cytochroms Cyp 2C9 (in 1 patient), 2C8 (in 1 patient), Cyp SA/4 (non discovered positivity) and finally UGT1A1*2B (discovered in 2 patients).

CONCLUSIONS: In the group of patients treated by rosuvastatin, we discovered not one case of rhabdomyolysis. In each patient with rhabdomyolysis (brown urine discoloration, mal-odorous urine, painful muscle cramps, muscle weakness, fatigue) at least one polymorphism of "statins´ genes" was present.

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