Any market share retained until then is worth a lot to Pfizer, Funtleyder said, noting the low cost of making the pills - about a dime each. While Lipitor and Crestor generate most of the money from cholesterol medicines, much-cheaper generic versions of three older statins - Zocor, Pravachol and Mevacor - account for almost two-thirds of statin prescriptions.
Those three generics saw a slight increase in the number of prescriptions filled from Nov. According to IMS, about , of the prescriptions filled for atorvastatin were from patients who had been on Lipitor, another , were from people on simvastatin generic Zocor and about 20, were from patients on Crestor. The whistleblower's claims raised serious questions about the integrity of Ranbaxy's manufacturing and the safety of its drugs.
The ensuing four-year investigation, in which the FDA has teamed with the U. Department of Justice, turned up disturbing evidence, according to government filings though none of the resulting allegations related to Lipitor.
Crucial tests to evaluate how quickly drugs degrade, meant to be conducted over a months-long period, were actually performed over just a few days, with the records falsified to conceal that. On certain days quality assurance supervisors who purported to be on-site were absent, and their signatures were falsified. In yet another lapse -- this one potentially life-threatening -- Ranbaxy risked cross-contamination of penicillin with other drug products by manufacturing them in close proximity.
Taken together, these and other forms of deception by Ranbaxy raised the possibility that what the FDA had approved and what patients were ingesting were two different things.
FDA inspectors were disturbed by what they found at the company's Paonta Sahib factory in India, where it planned to make generic Lipitor. They were "clearly shocked" that Ranbaxy was "totally flouting the rules," says one congressional investigator who later interviewed the inspectors.
By September the FDA had issued warning letters to Ranbaxy, describing what it referred to as "significant deficiencies" at Paonta Sahib and Dewas, the company's two biggest Indian plants. The FDA restricted the company from bringing some 30 drug products from those plants into the U.
It was a severe blow, and Ranbaxy began intensive efforts to reverse the FDA's decision. Even as the agency blocked Ranbaxy from importing the drugs, it did nothing to remove existing stocks of those same medications from U. Those decisions helped provoke an unusual twist: In February the FDA took another drastic step: Distribution[ edit ] The mean volume of distribution of atorvastatin is approximately L. Metabolism[ edit ] Atorvastatin metabolism is primarily through cytochrome P 3A4 hydroxylation to form active ortho- and parahydroxylated metabolites , as well as various beta-oxidation metabolites.
The ortho-hydroxy metabolite undergoes further metabolism via glucuronidation. As a substrate for the CYP3A4 isozyme, it has shown susceptibility to inhibitors and inducers of CYP3A4 to produce increased or decreased plasma concentrations, respectively. This interaction was tested in vitro with concurrent administration of erythromycin , a known CYP3A4 isozyme inhibitor, which resulted in increased plasma concentrations of atorvastatin. It is also an inhibitor of cytochrome 3A4. If it does not, it says something about our system.
Online pharmacies already are offering generic Lipitor. Of course, people with health insurance that covers prescription drugs will pay much less. And for at least the rest of the year, those in the "Lipitor for You" program will pay even less. The move reflects Merck's success in using rebates to PBMs to continue offering exclusively the more expensive brand drug. Plan sponsors need to evaluate their contracts to see how much, if any, of the Lipitor rebate money they receive.
It is unlikely they will receive any of it. Watson Pharmaceutical released the generic form on May 2, By the last week of December, atorvastatin pills from Ranbaxy Laboratories Ltd. That's because Pfizer is fighting hard to retain branded Lipitor sales, with big discounts to patients and insurers. New York-based Pfizer also has been giving insurance plans that agree to only cover brand-name Lipitor for the time being the difference between what they had been paying for the brand and what they would pay for cheaper generics.
Until recently, Pfizer has been heavily advertising the copay program, called "Lipitor For You," and is still running some ads.
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