CRESTOR TABLET 5mg

Indication

Used as an adjunct to dietary therapy to treat primary hyperlipidemia (heterozygous familial and nonfamilial), mixed dyslipidemia and hypertriglyceridemia. Also indicated for homozygous familial hypercholesterolemia as an adjunct to other lipid-lowering therapies or when other such therapies are not available. Furthermore, it is used to slow the progression of atherosclerosis and for primary prevention of cardiovascular disease.

Mechanism of Action

Rosuvastatin is a competitive inhibitor of HMG-CoA reductase. HMG-CoA reductase catalyzes the conversion of HMG-CoA to mevalonate, an early rate-limiting step in cholesterol biosynthesis. Rosuvastatin acts primarily in the liver. Decreased hepatic cholesterol concentrations stimulate the upregulation of hepatic low density lipoprotein (LDL) receptors which increases hepatic uptake of LDL. Rosuvastatin also inhibits hepatic synthesis of very low density lipoprotein (VLDL). The overall effect is a decrease in plasma LDL and VLDL. In vitro and in vivo animal studies also demonstrate that rosuvastatin exerts vasculoprotective effects independent of its lipid-lowering properties. Rosuvastatin exerts an anti-inflammatory effect on rat mesenteric microvascular endothelium by attenuating leukocyte rolling, adherence and transmigration (PMID: 11375257). The drug also modulates nitric oxide synthase (NOS) expression and reduces ischemic-reperfusion injuries in rat hearts (PMID: 15914111). Rosuvastatin increases the bioavailability of nitric oxide (PMID: 11375257, 12031849, 15914111) by upregulating NOS (PMID: 12354446) and by increasing the stability of NOS through post-transcriptional polyadenylation (PMID: 17916773). It is unclear as to how rosuvastatin brings about these effects though they may be due to decreased concentrations of mevalonic acid.

Pharmacokinetics

Absorption

Bioavailability is approximately 20%. Peak plasma concentrations were reached 3 to 5 hours following oral dosing. Both Cmax and AUC increased in approximate proportion to CRESTOR dose. Food has no effect on the AUC of rosuvastatin.

Distribution

* 134 L [steady-state]

Metabolism

Not extensively metabolized. Only ~10% is excreted as metabolite. Cytochrome P450 (CYP) 2C9 is primarily responsible for the formation of rosuvastatin's major metabolite, N-desmethylrosuvastatin. N-desmethylrosuvastatin has approximately 50% of the pharmacological activity of its parent compound in vitro. Rosuvastatin clearance is not dependent on metabolism by cytochrome P450 3A4 to a clinically significant extent. Rosuvastatin accounts for greater than 90% of the pharmacologic action. Inhibitors of CYP2C9 increase the AUC by less than 2-fold. This interaction does not appear to be clinically significant.

Elimination

Toxicity

Generally well-tolerated. Side effects may include myalgia, constipation, asthenia, abdominal pain, and nausea. Other possible side effects include myotoxicity (myopathy, myositis, rhabdomyolysis) and hepatotoxicity. To avoid toxicity in Asian patients, lower doses should be considered. Pharmacokinetic studies show an approximately two-fold increase in peak plasma concentration and AUC in Asian patients (Philippino, Chinese, Japanese, Korean, Vietnamese, or Asian-Indian descent) compared to Caucasians patients.

Active Ingredient/Synonyms

(3R,5S,6E)-7-(4-(4-fluorophenyl)-6-(1-methylethyl)-2-(ethyl(methylsulfonyl)amino)-5-pyrimidinyl)-3,5-dihydroxy-6-heptenoic acid | (3R,5S,6E)-7-{4-(4-fluorophenyl)-6-isopropyl-2-[methyl(methylsulfonyl)amino]pyrimidin-5-yl}-3,5-dihydroxyhept-6-enoic acid | Rosuvastatin |