
Don Vaughan is a freelance writer based in Raleigh, North Carolina.
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Pfizer Inc. is one of the worldâs largest research-based pharmaceutical and biomedical companies, known for developing, manufacturing, and marketing medications and vaccines for humans and animals. Among its best-known products are Zoloft, an antidepressant; Viagra, an erectile dysfunction medication; Xanax, an antidepressant and anxiolytic; and over-the-counter products such as ChapStick and Preparation H, a hemorrhoid treatment. Pfizer Inc. is headquartered in New York City.
Pfizer was established as Charles Pfizer & Company in 1849 in Brooklyn, New York, by cousins Charles Pfizer and Charles F. Erhart, both of whom had emigrated from Germany to the United States in 1848. The company focused on the manufacture of chemical compounds and found its first success with the development of an antiparasitic known as santonin. Shortly afterward, the company saw its fortunes climb further with the production of citric acid, which had numerous industrial uses.
The company continued to grow, and in 1881 transferred its administrative headquarters to Manhattan, followed by additional expansion into other regions of the United States. By 1906, Pfizerâs annual sales topped $3 million.
When World War I resulted in a global shortage of calcium citrateânecessary for the production of citric acidâPfizer was forced to seek an alternative. The solution was found in a fungus that created citric acid through the fermentation of sugar, and Pfizer began production of citric acid through this process in 1919. During World War II, the technology developed for the production of citric acid through sugar fermentation would also be used in the mass production of penicillin, a lifesaving antibiotic.
In addition to its prescription drugs, many household medicines, treatments, and vitamins are made by Pfizer, including:
With significant success behind it and the promise of rapid growth ahead, Pfizer incorporated in Delaware in June 1942.Starting in 1950, as profits from penicillin began to decline, the company started looking into new types of antibiotics. The first was oxytetracycline, discovered in 1950. This advance shifted Pfizer from a chemical manufacturer to a research-based pharmaceutical company. In 1959, Pfizer entered the animal health arena, supported by a research facility inside a 700-acre farm in Terre Haute, Indiana. Pfizer would go on to acquire other animal health companies, including Pharmacia Corp. and CSL Animal Health. Pfizer Animal Health, renamed Zoetis in 2012, continues to be a major player in the animal health field with vaccines, medications, and other products for household pets and large animals.
Pfizer experienced significant international expansion in the 1950s, establishing facilities in Canada, the United Kingdom, Mexico, and elsewhere, and in 1960 transferred its New York research operation to Groton, Connecticut.

The 1980s and 1990s saw the release of several new pharmaceutical products that would generate huge profits for Pfizer, starting in 1981 with the development of fluconazole (brand name: Diflucan), an oral treatment for an array of fungal infections. Five years later, the company received the worldwide rights to the macrolide antibiotic azithromycin (brand name: Zithromax) from Pliva, a pharmaceutical company based in Croatia; it quickly became the gold standard treatment for community-acquired pneumonia.
Numerous other drugs manufactured and marketed by Pfizer also proved to be strong sellers. They include:
Over its historyâand particularly in the early decades of the 21st centuryâPfizer has acquired or merged with several other pharmaceutical companies in the U.S. and abroad. It spent $110 billion in 2000 to purchase Warner-Lambert, but was forced by antitrust regulators to divest itself of several minor products in order to meet regulations.
The next big merger occurred in 2003, when Pfizer acquired Pharmacia, a deal that also included Searle and SUGEN; Pfizer closed the SUGEN facility soon after the deal, although several of the companyâs programs were folded into Pfizer, including the cancer treatment drug sunitinib (brand name: Sutent), which was approved by the Food and Drug Administration in 2006.
Other acquisitions by Pfizer include Wyeth in 2009, a deal that made Pfizer the worldâs largest pharmaceutical company; Innopharma in 2014; Redvax and Hospira in 2015; Anacor Pharmaceuticals in 2016; Therachon in 2019; and Amplyx Pharmaceuticals in 2021.
Traditionally, when a Pfizer drug would come off patent (typically after 20 years), the company would move it, along with any generic versions, to its Upjohn subsidiary. In November 2020, however, Pfizer acquired rival generic drugmaker Mylan, and merged itâalong with Upjohnâinto a new company, Viatris (VTRS). At the time of the merger, Pfizer and its shareholders held 57% of Viatris shares, with the remaining 43% issued to Mylan shareholders. The Viatris drug portfolio includes:
Pfizer joined forces with BioNTEch in March 2020 to develop an mRNA vaccine for COVID-19, a devastating virus that killed millions worldwide. Rather than accept money from the U.S. government for this initiative, Pfizer CEO Albert Bourla opted to use $2 billion of the companyâs money in an effort to avoid government interference. Four vaccine variations were developed, and two given the go-ahead for human testing by the Food and Drug Administration. One of the vaccines offered a 95% efficacy rate, as announced by Pfizer in November 2020, and the vaccine was quickly approved by several nations, including the United States.
In 2021, Pfizer complemented its COVID-19 vaccine with an oral antivirus treatment called Paxlovid, which proved to be effective for reducing symptom severity and keeping COVID-19 patients out of the hospital.
Pfizer has faced numerous lawsuits and recalls since its founding. In June 2022, for example, the company recalled the 0.5 mg and 1 mg tablets of its popular smoking cessation drug Chantix due to unacceptable levels of the cancer-causing compound N-nitroso-varenicline, and expanded the recall further in 2023. Years earlier, an estimated 3,000 people filed suit against Pfizer over Chantix, alleging suicidal ideation and other psychological disorders. In 2013, Pfizer put nearly $288 million aside to settle claims.
Pfizer holds the dubious distinction of paying the largest settlement in the history of the U.S. Justice Department for health care fraud: $2.3 billion. The settlement was finalized in 2009 after Pfizer subsidiary Pharmacia & Upjohn Company, Inc. pleaded guilty to misbranding the anti-inflammatory drug Bextra with intent to defraud or mislead. One billion dollars of the fine settled claims that Pfizer illegally promoted four drugs and sent false claims to government programs regarding uses that were not medically appropriate.
The company has also faced lawsuits and legal challenges over neurology treatments Lyrica and Geodon, transplant drug Rapamune, its Celebrex anti-inflammatory drug, and âlow-Tâ drug Depo-Testosterone. In the 2010s, Pfizer settled an estimated 13,000 lawsuits for $1.2 billion after allegations that hormone replacement drug Prempro (part of Pfizerâs 2009 Wyeth acquisition) increased the risk of breast cancer.
Pfizer started as a small company with big aspirations, and with the development of numerous important pharmaceuticals and over-the-counter products, became a world leader in its field. Growth through mergers and acquisitions kept it at the head of the pack, and the company saw its fortunes and reputation soar in 2020 with the development of an effective vaccine for COVID-19. Pfizer remains one of the worldâs top pharmaceutical innovators.
Don Vaughan