Simvastatin: Difference between revisions

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New page: <applet load="" size="480" color="" frame="true" spin="on" Scene ="User:David_Canner/Sandbox_crestor/Rosu/1" align="right" caption="Rosuvastatin, also known as Crestor"/> ===Better Know...
 
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<applet  load="" size="480" color="" frame="true"  spin="on" Scene ="User:David_Canner/Sandbox_crestor/Rosu/1" align="right" caption="Rosuvastatin, also known as Crestor"/>
<StructureSection load='' size='340' side='right' caption='Simvastatin, also known as Zocor' scene='Simvastatin/Just_simva/1'>
===Better Known as: Crestor===
===Better Known as: Zocor===
* Marketed By: AstraZeneca Plc.<br />
* Marketed By: Merck & Co. Inc.<br />
* Major Indication: Hyperlipidemia & High Cholesterol (Hypercholesterolemia)<br />
* Major Indication: Hyperlipidemia & High Cholesterol ([[Metabolic Disorders|Hypercholesterolemia]])<br />
* Drug Class: [[HMGR]] Inhibitor or Statin
* Drug Class: [[HMGR]] Inhibitor or Statin
* Date of FDA Approval (Patent Expiration): 2003 (2016)<br />
* Date of FDA Approval (Patent Expiration): 1997 (2006)<br />
* 2009 Sales: $4.5 Billion <ref>http://www.reuters.com/article/idUSN2223558720100222</ref>
* 2005 Sales: $4.4 Billion <ref>http://money.cnn.com/2006/06/23/news/companies/zoloft_zocor/index.htm</ref>
* Why You Should Care: Sales of Crestor are the fastest growing among the statins. Statins are so ubiquitous, doctors have even suggested handing them out with fast food. See: [http://www.bbc.co.uk/news/health-10955522 the article] <br />
* Importance: Zocor is one of the best selling drugs of all time and was the second best selling drug in 2005 before going off patent. Since statins are so ubiquitous, doctors have even suggested handing them out with fast food. See: [http://www.bbc.co.uk/news/health-10955522 the article] <br />
* The following is a list of Pharmacokinetic Parameters. See: [[Pharmaceutical Drugs]] for more information
* See [[Pharmaceutical Drugs]] for more information about other drugs and disorders
 
===Mechanism of Action===
===Mechanism of Action===
[[Rosuvastatin]] is an inhibitor of [[HMG-CoA Reductase]] (HMGR), a <scene name='Rosuvastatin/Statin_rosu/2'>highly regulated enzyme</scene> responsible for the committed step in cholesterol synthesis. Rosuvastatin, like most of the statins, <scene name='HMG-CoA_Reductase/Statin_rosu/6'>binds HMGR</scene> via a number of polar interactions with the "cis loop" of HMGR, particularly residues Ser 684, Asp 690, Lys 691, Lys 692, and hydrogen bond interactions between Glu 559 and Asp 767 with the O5-hydroxyl of the statins. Van der Waals interactions between Leu 562, Val 683, Leu 853, Ala 856, and Leu 857 of HMGR and hydrophobic ring structures of Rosuvastatin contribute to binding as well.<ref>PMID:11349148</ref> These interactions help Rosuvastatin outcompete HMG-CoA, the substrate of HMGR, in binding to HMGR.<ref>PMID:7784310</ref>
Simvastatin is rapidly hydrolyzed ''in vivo'' to generate mevinolinic acid, a powerful inhibitor of [[HMG-CoA Reductase]] (HMGR). HMGR is a <scene name='Simvastatin/Just_simva_hmg/1'>highly regulated enzyme</scene> responsible for the committed step in cholesterol synthesis. Simvastatin, like other statins, <scene name='Simvastatin/Statin_simva/1'>binds HMGR</scene> via a number of polar interactions with the "cis loop" of HMGR, particularly residues Ser 684, Asp 690, Lys 691, Lys 692, and hydrogen bond interactions between Glu 559 and Asp 767 with the O5-hydroxyl of the statins. Van der Waals interactions between Leu 562, Val 683, Leu 853, Ala 856, and Leu 857 of HMGR and hydrophobic ring structures of Simvastatin help form the pocket the drug is positioned in.<ref>PMID:11349148</ref> These interactions help Simvastatin outcompete HMG-CoA, the substrate of HMGR, in binding to HMGR.<ref>PMID:7784310</ref>
 
</StructureSection>
===Pharmacokinetics===
===Pharmacokinetics===
 
<table style="background: cellspacing="0px" align="" cellpadding="0px" width="42%">  
{| class="wikitable" border="1" width="48%" style="text-align:center"
<tr>
|-
<td style="width:100%; vertical-align:top;border-width:0px; border-style:inset">
!  colspan="6" align="center"| Statin PK Comparison at 10mg doses<ref>PMID:15198967</ref><ref>PMID:12686673</ref><ref>PMID:18176327</ref><ref>PMID: 17452418</ref>
<div style="height:100%; width: 100%">
|-
{{:Statin Pharmacokinetics}}
! Parameter
</div>
! [[Atorvastatin]] (Lipitor)
</td>
! Fluvastatin (Lescol)
</tr>
! Lovastatin (Mevacor)
</table>
! [[Simvastatin]] (Zocor)
! [[Rosuvastatin]] (Crestor)
|-
! [[Pharmaceutical_Drugs#Tmax|T<sub>max</sub>]] (hr)
! 2.5
! 1
! 3
! 1.5
! 4
|-
! [[Pharmaceutical_Drugs#Cmax|C<sub>max</sub>]] (ng/ml)
! 27-66
! 448
! 10-20
! 7.3
!4.34
|-
! [[Pharmaceutical_Drugs#Bioavailability_.28F.29|Bioavailability]] (%)
! 12
! 19-29
! 5
! 5
! 20
|-
! [[Pharmaceutical_Drugs#Protein_Binding|Protein Binding]] (%)
! 80-90
! 99
! 95
! 95
! 88
|-
! [[Pharmaceutical_Drugs#Half_Life_.28T1.2F2.29|T<sub>1/2</sub>]] (hr)
! 15-30
! 2
! 3
! 2.7
! 19
|-
! [[Pharmaceutical_Drugs#Area_Under_the_Curve_.28AUC.29|AUC]] (ng/ml/hr)
! 104
!
! 33
! 125
! 48
|-
! [[Pharmaceutical_Drugs#Inhibitory_Concentration_.28IC50.29|IC<sub>50</sub>]] (nM)
! 154
! 198
! 800-4200
! 66
! 320
|-
! Equivalent LDL Reduction Dosage (mg)
! 10
!
! 80
! 20
! 5
|-
! Metabolism
! Hepatic <br/>(CYP3A4)
! Hepatic <br/>(CYP2C9)
! Hepatic <br/>(CYP3A4)
! Hepatic <br/>(CYP3A4)
! Not <br/>Metabolized
|}


===Effectiveness and Side Effects===
===Effectiveness and Side Effects===
====Effectiveness====
====Effectiveness====
Rosuvastatin has the greatest efficacy compared to other statins at the same dosage. At 5mg, patients experienced a 40% or greater reduction in LDL as compared to similar results for [[Atorvastatin]] at 20mg doses. <ref>PMID:20456733</ref>
At the 20mg dose, Simvastatin reduces LDL concentration by 30-40%, in line with 5mg of Rosuvastatin ([[Crestor]]) and 10mg of Atorvastatin ([[Lipitor]]). Of particular note, at the 20mg dosage, Simvastatin had the most variable results, with patients experiencing drops in LDL ranging from 20%, well below the minimum of Crestor and Lipitor, to as high as 55%, as high as the maximum, 80mg dosage of Lipitor. At 80mg, Atorvastatin appears to be more effective at preventing coronary heart disease compared to 20mg Simvastatin, but considering the variation in dosage level, it is difficult to directly compare these results. <ref>PMID:11464446</ref><ref>PMID:20456733</ref>
====Side Effects====
====Side Effects====
Although all of the statins are generally considered safe, rosuvastatin had a higher reported adverse event rate than other statin clinical trials. Typical adverse events include muscle weakness, headache dizziness and slightly increased creatinine kinase (CK) levels (an indication of kidney and smooth muscle damage), although these are common to all the statins (with the exception of elevated CK levels which only occurs in [[Atorvastatin]], Rosuvastatin, and [[Simvastatin]])<ref>PMID:20456733</ref>
The Statins are one of the safest drug classes to reach block buster status. Typical adverse events include muscle weakness, headache dizziness and slightly increased creatinine kinase (CK) levels (an indication of kidney and smooth muscle damage), although these are common to all the statins (with the exception of elevated CK levels which only occurs in [[Atorvastatin]], [[Rosuvastatin]], and Simvastatin)<ref>PMID:20456733</ref> In March, 2010, the FDA issued a warning about an increased rate of Rhabdomyolysis, a dangerous breakdown of muscle fiber, releasing [[myoglobin]] into the bloodstream, potentially resulting in severe kidney damage. Although these concerns are not enough to have patients cease use of Zocor, it is important for the public to be aware of the issue. <ref>http://www.reuters.com/article/idUSTRE62I3YW20100319</ref>
===Interesting Facts===
===Interesting Facts===
* Rosuvastatin  has made recent headlines as being nearly equivalent in efficacy to Lipitor, but also cuts the rate of heart attacks and strokes significantly. <ref>PMID:20026779</ref>
* As with other statins which are metabolized by the CYP3A4 liver enzyme, the pharmacokinetics of Simvastatin are altered significantly by consumption of grapefruit juice. C<sub>max</sub> values of Simvastatin (40mg doses) increased by nearly 300%, t<sub>max</sub> increased 100%,, the half life decreased by 50%, and AUC increased by nearly 300%. These results are even more pronounced for active Simvastatin metabolites. <ref>DOI: 10.1111/j.1365-2125.2004.02095.x</ref>
* Unlike other statins, consuming grapefruit juice does not affect the PKs of rosuvastatin. <ref>PMID:9585793</ref> <ref>PMID: 11836106</ref>
* Simvastatin is simply the methyalted form of [[Lovastatin]] an earlier Statin developed by Merck.
* Studies have reveal that that Asians appear to process rosuvastatin differently than members of other races with C<sub>max</sub> and AUC reaching levels which were over 2 fold greater. The FDA has subsequently announced that asians should take half the standard dose to achieve the same cholesterol lowering benefit. <ref>PMID:16198652</ref>
===The Jist===
===The Jist===
The statins are generally viewed as very safe and have been proven effective over the past 15 years. Rosuvastatin is the newest major blockbuster statin and was designed to be taken at lower levels than other statins. Recent studies have indicated rosuvastatin can reduce the likely hood of myocardial infarction and stroke, although this has been refuted by some studies. Truth be told, with major statins like Lipitor coming off patent in the next year or two, pharmaceutical companies are looking for new diseases that can be treated by still-patented statins like Rosuvastatin (Patent expires in 2016). With $4 billion in sales per year and Lipitor going off patent in 2011, resulting in a dramatic price drop in statins as generics flood the market, proving that Rosuvastatin reduces heart attacks, etc. would be worth many billions of dollars. It remains to be seen whether the potential reduction in heart ailments while taking Rosuvastatin, if it exists, can be proven with statistical significance.  
Along with the other statins, Simvastatin works well and is quite safe. Depending upon the patient, Simvastatin can be the most effective statin at reducing LDL, but can also have dramatically reduced efficacy. Since Simvastatin is the most powerful HMGR inhibitor with an IC<sub>50</sub> of 66nM, this allows for decreased long-term exposure to the drug (lower AUC) and negates the short half life of Simvastatin compared to Atorvastatin and Rosuvastatin. While on patent it was one of the best selling drugs in the world. To maintain its market share after losing patent protection, Merck dramatically reduced the price of Zocor for insurance companies well below the price of existing statin generics, making the drug particularly attractive to US Health Insurers looking to reduce costs. <ref>http://timesofindia.indiatimes.com/business/india-business/Mercks-Zocor-price-cut-a-mixed-bag-for-drug-cos/articleshow/1690722.cms</ref>
===References===
===References===
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Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

David Canner, Alexander Berchansky