Pfizer Inc. /ˈfaɪzər/ is an American multinational pharmaceutical corporation headquartered in New York City, with its research headquarters in Groton, Connecticut. It is among the world's largest pharmaceutical companies. Pfizer is listed on the New York Stock Exchange, and its shares have been a component of the Dow Jones Industrial Average since 2004.
Pfizer develops and produces medicines and vaccines for a wide range of medical disciplines, including immunology, oncology, cardiology, diabetology/endocrinology, and neurology. Pfizer's products include the blockbuster drug Lipitor (atorvastatin), used to lower LDL blood cholesterol; Lyrica (pregabalin) for neuropathic pain/fibromyalgia; Diflucan (fluconazole), an oral antifungal medication; Zithromax (azithromycin), an antibiotic; Viagra (sildenafil) for erectile dysfunction; and Celebrex/Celebra (celecoxib), an anti-inflammatory drug.
Pfizer was founded in 1849 by cousins Charles Pfizer and Charles F. Erhart in New York City as a manufacturer of fine chemicals. Its discovery of Terramycin (oxytetracycline) in 1950 put it on a path towards becoming a research-based pharmaceutical company. Pfizer has made numerous acquisitions, including Warner–Lambert in 2000, Pharmacia in 2003, and Wyeth in 2009 (the largest of the three at $68 billion).
In 2016, Pfizer Inc. is expected to merge with Allergan plc, in a deal worth $160 billion, to create the Ireland-based "Pfizer plc". (Source: Wikipedia)