Xentor

Uses

Xentor is an HMG-CoA reductase inhibitor used to lower lipid levels and reduce the risk of cardiovascular disease including myocardial infarction and stroke.

Xentor is indicated for the treatment of several types of dyslipidemias, including primary hyperlipidemia and mixed dyslipidemia in adults, hypertriglyceridemia, primary dysbetalipoproteinemia, homozygous familial hypercholesterolemia, and heterozygous familial hypercholesterolemia in adolescent patients with failed dietary modifications.

Dyslipidemia describes an elevation of plasma cholesterol, triglycerides or both as well as to the presence of low levels of high-density lipoprotein. This condition represents an increased risk for the development of atherosclerosis.

Xentor is indicated, in combination with dietary modifications, to prevent cardiovascular events in patients with cardiac risk factors and/or abnormal lipid profiles.

Xentor can be used as a preventive agent for myocardial infarction, stroke, revascularization, and angina, in patients without coronary heart disease but with multiple risk factors and in patients with type 2 diabetes without coronary heart disease but multiple risk factors.

Xentor may be used as a preventive agent for non-fatal myocardial infarction, fatal and non-fatal stroke, revascularization procedures, hospitalization for congestive heart failure and angina in patients with coronary heart disease.

Prescribing of statin medications is considered standard practice following any cardiovascular events and for people with a moderate to high risk of development of CVD. Statin-indicated conditions include diabetes mellitus, clinical atherosclerosis (including myocardial infarction, acute coronary syndromes, stable angina, documented coronary artery disease, stroke, trans ischemic attack (TIA), documented carotid disease, peripheral artery disease, and claudication), abdominal aortic aneurysm, chronic kidney disease, and severely elevated LDL-C levels.

Xentor is also used to associated treatment for these conditions: Anginal Pain, Cardiovascular Disease (CVD), Coronary Artery Disease (CAD), Coronary artery thrombosis, Dysbetalipoproteinemia, Fredrickson Type III lipidemia, Heterozygous Familial Hypercholesterolemia, High Blood Pressure (Hypertension), High Cholesterol, Homozygous Familial Hypercholesterolemia, Hospitalizations, Hypertriglyceridemias, Mixed Dyslipidemias, Mixed Hyperlipidemia, Myocardial Infarction, Non-familial hypercholesterolemia, Postoperative Thromboembolism, Primary Hypercholesterolemia, Stroke, Transient Ischemic Attack, Elevation of serum triglyceride levels, Heterozygous familial hyperlipidemia, Non-familial hyperlipidemia, Non-fatal myocardial infarction, Primary Hyperlipidemia, Revascularization procedures, Revascularization process, Thrombotic events, Cardiovascular Primary Prevention, Secondary prevention cardiovascular event

How Xentor works

Xentor is a statin medication and a competitive inhibitor of the enzyme HMG-CoA (3-hydroxy-3-methylglutaryl coenzyme A) reductase, which catalyzes the conversion of HMG-CoA to mevalonate, an early rate-limiting step in cholesterol biosynthesis. Xentor acts primarily in the liver, where decreased hepatic cholesterol concentrations stimulate the upregulation of hepatic low-density lipoprotein (LDL) receptors, which increases hepatic uptake of LDL. Xentor also reduces Very-Low-Density Lipoprotein-Cholesterol (VLDL-C), serum triglycerides (TG) and Intermediate Density Lipoproteins (IDL), as well as the number of apolipoprotein B (apo B) containing particles, but increases High-Density Lipoprotein Cholesterol (HDL-C).

In vitro and in vivo animal studies also demonstrate that atorvastatin exerts vasculoprotective effects independent of its lipid-lowering properties, also known as the pleiotropic effects of statins. These effects include improvement in endothelial function, enhanced stability of atherosclerotic plaques, reduced oxidative stress and inflammation, and inhibition of the thrombogenic response. Statins were also found to bind allosterically to β2 integrin function-associated antigen-1 (LFA-1), which plays an essential role in leukocyte trafficking and T cell activation.

Toxicity

The reported LD50 of oral atorvastatin in mice is higher than 5000 mg/kg. In cases of overdose with atorvastatin, there is reported symptoms of complicated breathing, jaundice, liver damage, dark urine, muscle pain, and seizures. In case of overdose, symptomatic treatment is recommended and due to the high plasma protein binding, hemodialysis is not expected to generate significant improvement.

In carcinogenic studies with high doses of atorvastatin, evidence of rhabdomyosarcoma, fibrosarcoma, liver adenoma, and liver carcinoma were observed.

In fertility studies with high doses of atorvastatin, there were events of aplasia, aspermia, low testis and epididymal weight, decreased sperm motility, decreased spermatid head concentration and increased abnormal sperm.

Xentor was shown to not be mutagenic in diverse mutagenic assays.

Food Interaction

• Avoid grapefruit products. Grapefruit products may increase the risk for atorvastatin related adverse effects such as myopathy and rhabdomyolysis.
• Take with or without food. Food decreases absorption but not to a clinically significant extent.

[Moderate] GENERALLY AVOID: Coadministration with grapefruit juice may increase the plasma concentrations of atorvastatin.

The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit.

When a single 40 mg dose of atorvastatin was coadministered with 240 mL of grapefruit juice, atorvastatin peak plasma concentration (Cmax) and systemic exposure (AUC) increased by 16% and 37%, respectively.

Greater increases in Cmax (up to 71%) and

Clinically, high levels of HMG-CoA reductase inhibitory activity in plasma is associated with an increased risk of musculoskeletal toxicity.

Myopathy manifested as muscle pain and

Rhabdomyolysis has also occurred rarely, which may be accompanied by acute renal failure secondary to myoglobinuria and may result in death.

ADJUST DOSING INTERVAL: Fibres such as oat bran and pectin may diminish the pharmacologic effects of HMG-CoA reductase inhibitors by interfering with their absorption from the gastrointestinal tract.

MANAGEMENT: Patients receiving therapy with atorvastatin should limit their consumption of grapefruit juice to no more than 1 liter per day.

Patients should be advised to promptly report any unexplained muscle pain, tenderness or weakness, particularly if accompanied by fever, malaise and

Therapy should be discontinued if creatine kinase is markedly elevated in the absence of strenuous exercise or if myopathy is otherwise suspected or diagnosed.

In addition, patients should either refrain from the use of oat bran and pectin or, if concurrent use cannot be avoided, to separate the administration times by at least 2 to 4 hours.

Xentor Alcohol interaction

[Moderate]

Concomitant use of statin medication with substantial quantities of alcohol may increase the risk of hepatic injury.

Transient increases in serum transaminases have been reported with statin use and while these increases generally resolve or improve with continued therapy or a brief interruption in therapy, there have been rare postmarketing reports of fatal and non-fatal hepatic failure in patients taking statins.

Patients who consume substantial quantities of alcohol and/or have a history of liver disease may be at increased risk for hepatic injury.

Active liver disease or unexplained transaminase elevations are contraindications to statin use.

Patients should be counseled to avoid substantial quantities of alcohol in combination with statin medications and clinicians should be aware of the increased risk for hepatotoxicity in these patients.

Xentor Drug Interaction

Unknown: aspirin, aspirin, aspirin, aspirin, ubiquinone, ubiquinone, apixaban, apixaban, omega-3 polyunsaturated fatty acids, omega-3 polyunsaturated fatty acids, metoprolol, metoprolol, metoprolol, metoprolol, cyanocobalamin, cyanocobalamin, ascorbic acid, ascorbic acid, cholecalciferol, cholecalciferol

Xentor Disease Interaction

Major: liver disease, rhabdomyolysisModerate: cognitive impairment, diabetes, renal disease

Volume of Distribution

The reported volume of distribution of atorvastatin is of 380 L.

Elimination Route

Xentor presents a dose-dependent and non-linear pharmacokinetic profile. It is very rapidly absorbed after oral administration. After the administration of a dose of 40 mg, its peak plasma concentration of 28 ng/ml is reached 1-2 hours after initial administration with an AUC of about 200 ng∙h/ml. Xentor undergoes extensive first-pass metabolism in the wall of the gut and the liver, resulting in an absolute oral bioavailability of 14%. Plasma atorvastatin concentrations are lower (approximately 30% for Cmax and AUC) following evening drug administration compared with morning. However, LDL-C reduction is the same regardless of the time of day of drug administration.

Administration of atorvastatin with food results in prolonged Tmax and a reduction in Cmax and AUC.

Breast Cancer Resistance Protein (BCRP) is a membrane-bound protein that plays an important role in the absorption of atorvastatin. Evidence from pharmacogenetic studies of c.421C>A single nucleotide polymorphisms (SNPs) in the gene for BCRP has demonstrated that individuals with the 421AA genotype have reduced functional activity and 1.72-fold higher AUC for atorvastatin compared to study individuals with the control 421CC genotype. This has important implications for the variation in response to the drug in terms of efficacy and toxicity, particularly as the BCRP c.421C>A polymorphism occurs more frequently in Asian populations than in Caucasians. Other statin drugs impacted by this polymorphism include fluvastatin, simvastatin, and rosuvastatin.

Genetic differences in the OATP1B1 (organic-anion-transporting polypeptide 1B1) hepatic transporter encoded by the SCLCO1B1 gene (Solute Carrier Organic Anion Transporter family member 1B1) have been shown to impact atorvastatin pharmacokinetics. Evidence from pharmacogenetic studies of the c.521T>C single nucleotide polymorphism (SNP) in the gene encoding OATP1B1 (SLCO1B1) demonstrated that atorvastatin AUC was increased 2.45-fold for individuals homozygous for 521CC compared to homozygous 521TT individuals.[A181493] Other statin drugs impacted by this polymorphism include simvastatin, pitavastatin, rosuvastatin, and pravastatin.

Half Life

The half-life of atorvastatin is 14 hours while the half-life of its metabolites can reach up to 30 hours.

Clearance

The registered total plasma clearance of atorvastatin is of 625 ml/min.

Elimination Route

Xentor and its metabolites are mainly eliminated in the bile without enterohepatic recirculation. The renal elimination of atorvastatin is very minimal and represents less than 1% of the eliminated dose.

Innovators Monograph

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