Drug information of Pitavastatin

Pitavastatin 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. Pitavastatin acts primarily in the liver, where decreased hepatic cholesterol concentrations stimulate the upregulation of hepatic low density lipoprotein (LDL) receptors which increase hepatic uptake of LDL, thereby reducing circulating LDL-C levels.

In vitro and in vivo animal studies also demonstrate that statins exert vasculoprotective effects independent of their lipid-lowering properties, also known as the pleiotropic effects of statins. This includes improvement in endothelial function, enhanced stability of atherosclerotic plaques, reduced oxidative stress and inflammation, and inhibition of the thrombogenic response.

Statins have also been found to bind allosterically to β2 integrin function-associated antigen-1 (LFA-1), which plays an important role in leukocyte trafficking and in T cell activation.

Pitavastatin is an oral antilipemic agent which inhibits HMG-CoA reductase. It is used to lower total cholesterol, low density lipoprotein-cholesterol (LDL-C), apolipoprotein B (apoB), non-high density lipoprotein-cholesterol (non-HDL-C), and trigleride (TG) plasma concentrations while increasing HDL-C concentrations. High LDL-C, low HDL-C and high TG concentrations in the plasma are associated with increased risk of atherosclerosis and cardiovascular disease. The total cholesterol to HDL-C ratio is a strong predictor of coronary artery disease and high ratios are associated with higher risk of disease. Increased levels of HDL-C are associated with lower cardiovascular risk. By decreasing LDL-C and TG and increasing HDL-C, rosuvastatin reduces the risk of cardiovascular morbidity and mortality.

Elevated cholesterol levels, and in particular, elevated low-density lipoprotein (LDL) levels, are an important risk factor for the development of CVD. Use of statins to target and reduce LDL levels has been shown in a number of landmark studies to significantly reduce the risk of development of CVD and all-cause mortality. Statins are considered a cost-effective treatment option for CVD due to their evidence of reducing all-cause mortality including fatal and non-fatal CVD as well as the need for surgical revascularization or angioplasty following a heart attack. Evidence has shown that even for low-risk individuals (with <10% risk of a major vascular event occurring within 5 years) statins cause a 20%-22% relative reduction in major cardiovascular events (heart attack, stroke, coronary revascularization, and coronary death) for every 1 mmol/L reduction in LDL without any significant side effects or risks.

Pitavastatin may cause myopathy (muscle pain, tenderness, or weakness with creatine kinase (CK) above ten times the upper limit of normal) and rhabdomyolysis (with or without acute renal failure secondary to myoglobinuria). Rare fatalities have occurred as a result of rhabdomyolysis with statin use, including pitavastatin. Predisposing factors for myopathy include advanced age (≥65 years), female gender, uncontrolled hypothyroidism, and renal impairment. In most cases, muscle symptoms and CK increases resolved when treatment was promptly discontinued. As dosages of pitavastatin greater than 4mg per day were associated with an increased risk of severe myopathy, the product monograph recommends a maximum daily dose of 4mg once daily.

The risk of myopathy during treatment with pitavstatin may be increased with concurrent administration of interacting drugs such as fenofibrate, niacin, gemfibrozil, an d cyclosporine. Cases of myopathy, including rhabdomyolysis, have been reported with HMG-CoA reductase inhibitors coadministered with colchicine, and caution should therefore be exercised when prescribing these two medications together.

Real-world data from observational studies has suggested that 10-15% of people taking statins may experience muscle aches at some point during treatment.

Increases in serum transaminases have been reported with pitavastatin. In most cases, the elevations were transient and either resolved or improved on continued therapy or after a brief interruption in therapy. There have been rare postmarketing reports of fatal and non-fatal hepatic failure in patients taking statins, including pitavastatin.

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

Increases in HbA1c and fasting serum glucose levels have been reported with statins, including pitavastatin. Optimize lifestyle measures, including regular exercise, maintaining a healthy body weight, and making healthy food choices.

An in vitro study found that atorvastatin, pravastatin, rosuvastatin, and pitavastatin exhibited a dose-dependent cytotoxic effect on human pancreas islet β cells, with reductions in cell viability of 32, 41, 34 and 29%, respectively, versus control. Moreover, insulin secretion rates were decreased by 34, 30, 27 and 19%, respectively, relative to control

absorption:
Pitavastatin peak plasma concentrations are achieved about 1 hour after oral administration. Both Cmax and AUC0-inf increased in an approximately dose-proportional manner for single pitavastatin doses from 1 mg to 24 mg once daily. The absolute bioavailability of pitavastatin oral solution is 51%. The Cmax and AUC of pitavastatin did not differ following evening or morning drug administration. In healthy volunteers receiving 4 mg pitavastatin, the percent change from baseline for LDL-C following evening dosing was slightly greater than that following morning dosing. Pitavastatin was absorbed in the small intestine but very little in the colon.

Compared to other statins, pitavastatin has a relatively high bioavailability, which has been suggested to occur due to enterohepatic reabsorption in the intestine following intestinal absorption.

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 pitavastatin pharmacokinetics. Evidence from pharmacogenetic studies of the c.521T>C single nucleotide polymorphism (SNP) in the gene encoding OATP1B1 (SLCO1B1) demonstrated that pitavastatin AUC was increased 3.08-fold for individuals homozygous for 521CC compared to homozygous 521TT individuals. Other statin drugs impacted by this polymorphism include simvastatin, pitavastatin, atorvastatin, and rosuastatin. Individuals with the 521CC genotype may be at increased risk of dose-related adverse effects including myopathy and rhabdomyolysis due to increased exposure to the drug.
volume of distribution: 148L
protein binding:
    Pitavstatin is more than 99% protein bound in human plasma, mainly to albumin and alpha 1-acid glycoprotein.
metabolism:
The principal route of pitavastatin metabolism is glucuronidation via liver uridine 5'-diphosphate glucuronosyltransferase (UGT) with subsequent formation of pitavastatin lactone. There is only minimal metabolism by the cytochrome P450 system. Pitavastatin is marginally metabolized by CYP2C9 and to a lesser extent by CYP2C8. The major metabolite in human plasma is the lactone, which is formed via an ester-type pitavastatin glucuronide conjugate by UGTs (UGT1A3 and UGT2B7).
half-life:

The mean plasma elimination half-life is approximately 12 hours.

Recommended starting dose: 2 mg PO qDay

May increase to 4 mg PO qDay if necessary

Increased HbA1c and fasting serum glucose levels reported with statins; optimize lifestyle measures, including regular exercise, maintaining healthy body weight, and making healthy food choices

Increased serum transaminases reported; typically, elevations are transient and either resolved or improved on continued therapy or after briefly interrupting therapy

Myopathy (muscle pain, tenderness, or weakness with creatine kinase [CK] >10 x ULN) and rhabdomyolysis (with or without acute renal failure secondary to myoglobinuria) reported with statins; rare fatalities have occurred as a result of rhabdomyolysis

Myopathy risk factors include: age ≥65 yr, uncontrolled hypothyroidism, renal impairment, coadministration of drugs that decrease statin clearance or add to myopathy risk

Pitavastatin doses >4 mg/day were associated with increased risk for severe myopathy in clinical trials

Contraindicated for use in pregnant women since safety in pregnant women has not been established and there is no apparent benefit to therapy during pregnancy; therapy should be discontinued as soon as pregnancy is recognized

May cause fetal harm when administered to a pregnant woman; advise females of reproductive potential to use effective contraception during therapy