EFFECTS OF PRAVASTATIN TREATMENT ON VITAMIN-D METABOLITES

Hyperlipidemias, and notably hypercholesterolemia, represent important risk factors for atherosclerotic vascular disease. The enzymatic inhi bitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase, a selective and specific key enzyme involved in endogenous cholesterol synthesis, cause a significant mean reduction in low-density lipoprotein (LDL) c holesterol, both in familial and nonfamilial hypercholesterolemic form s. It has been hypothesized that these compounds might interfere with vitamin D endogenous synthesis secondarily to their effects on cholest erol. To verify this hypothesis, we studied 14 hypercholesterolemic pa tients treated as follows: 4 weeks of low-lipid, fiber-rich diet follo wed by 8 weeks of pravastatin treatment at the oral evening dose of 20 mg/d and by a 1-month washout period. No significant changes in serum calcium, 25-hydroxyvitamin D, and 1,25-dihydroxyvitamin D were notice d; on the contrary, significant (P < 0.01) reductions in total cholest erol and LDL cholesterol and a significant (P < 0.05) increase in high -density lipoprotein cholesterol were observed. After the final 1-mont h washout period, all values returned to baseline levels. In conclusio n, our study confirms the clinical efficacy of pravastatin on lipid fr actions and demonstrates the absence of any interference on the circul ating levels of the main vitamin D metabolites.