A COMPARISON OF THE EFFECTS OF SIMVASTATIN AND PRAVASTATIN MONOTHERAPY ON MUSCLE HISTOLOGY AND PERMEABILITY IN HYPERCHOLESTEROLEMIC PATIENTS

1 In this double-blind, placebo controlled, prospective study, it was assessed whether simvastatin or pravastatin monotherapy have adverse effects on muscle histology and muscle membrane permeability in hypercholesterolaemic patients. 2 Twenty-four patients, seven females and 17 males, with primary hypercholesterolaemia (LDL cholesterol levels greater than or equal to 4.14 mmol 1(-1)) were selected from the outpatient lipid clinic of a 650 bed academic medical centre. 3 After a 6-week lipid lowering diet and placebo period, patients were randomized into two groups of 12 subjects with similar characteristics, to receive either simvastatin or pravastatin in dosages of 10-40 mg day(-1) for three periods of 6 weeks. After each 3-week period the dose was adjusted to LDL cholesterol to aim for equipotent dosage. 4 All subjects performed a 45 min, lean body mass standardized bicycle ergometer test, before and after 18 weeks of treatment. As parameter for muscle damage, the exercise-induced rise of the muscle proteins, creatine kinase (CK) and myoglobin (Mb), relative to pre-exercise levels, were determined 1 and 8 h after the test. Forty-eight hours after each test a biopsy was taken from the quadriceps muscle and histology was judged by three independent observers. 5 Eighteen weeks of monotherapy with simvastatin and pravastatin did not affect the exercise induced release of CK and Mb, neither were any differences observed in muscle histology before and after treatment with either of the drugs. 6 Although simvastatin doses were lower than pravastatin, reductions in total- and LDL-cholesterol were greater in the simvastatin treated patients than in the pravastatin treated group. 7 We conclude that no evidence is found for muscle damage after 18 weeks of monotherapy with equipotent doses of either simvastatin or pravastatin.