Barr Laboratories Inc. was founded in
New York in 1970 by Edwin A. Cohen.
Starting in 1991 Barr Laboratories was involved in a scandal stemming from their violation of GMP regulations concerning handling of out-of-specification (OOS) test results.
In 1993 Barr Labs lost a lawsuit stemming from these findings, resulting in new industry interpretations of FDA regulations regarding out of specification test results. 
In 1993, Bruce L. Downey joined the company as its
president and in 1994, he became chairman and chief executive officer of the company.
In 1993, the company settled a
patent infringement case and began distributing a generic version of tamoxifen citrate, a treatment for breast cancer.
In 1995, the company received approval to manufacture and sell a generic version of
zidovudine (AZT), a treatment for AIDS.
In 1996, the company became the first to receive approval from the
Food and Drug Administration to market generic Warfarin, which was previously only sold by DuPont.
In 2001, the company acquired Duramed Pharmaceuticals for $589 million in stock.
In August 2001, after a 5-year legal battle with
Eli Lilly and Company, the company began selling a generic version of Prozac.
In 2003, the company acquired Endeavor Pharmaceuticals for $35 million.
In October 2006, the company acquired
On December 23, 2008, the company was acquired by
Teva Pharmaceutical Industries and became part of Teva Active Pharmaceutical Ingredients (TAPI).
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"Barr Pharmaceuticals, Inc. 2007 Form 10-K Annual Report". U.S. Securities and Exchange Commission.
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"TEVA COMPLETES ACQUISITION OF BARR" (Press release). Pliva. December 23, 2008. Archived from the original on April 20, 2017 . Retrieved . March 2, 2018
"Teva buys Barr Pharmaceuticals". The Jerusalem Post | JPost.com . Retrieved . 2018-11-18
"Barr Pharmaceuticals, Inc. History". FundingUniverse . Retrieved . June 25, 2018
"BARR LABS SHUTDOWN SOUGHT BY FDA DUE TO GMP VIOLATIONS UNCOVERED DURING AGENCY INSPECTIONS; FIRM CLAIMS FDA STANCE IS RETALIATION FOR WHISTLEBLOWING". PinkSheet . Retrieved . April 8, 2019
"A History of the OOS Problem". Biopharm International . Retrieved . April 8, 2019
"Former Barr CEO Downey joins NewSpring Capital". . March 11, 2009. American City Business Journals
"PATENT SETTLEMENT LIFTS BARR LABORATORIES SHARES". . March 9, 1993. The New York Times
"BARR LABORATORIES WINS F.D.A. APPROVAL FOR GENERIC AZT". . February 28, 1995. The New York Times
FOSS, KRISTA (October 26, 2001). "BITTER PILL". . The Globe and Mail
"Barr to Buy Duramed in a Stock Swap". . Los Angeles Times Reuters. June 30, 2001.
PETERSEN, MELODY (August 2, 2001). "Drug Maker Is Set to Ship Generic Prozac". . The New York Times
"COMPANY BRIEFS". . December 4, 2003. The New York Times
"Barr Acquires PLIVA d.d." (Press release). Pliva. October 12, 2006.