Pfizer pfabricates pfarmaceuticals pfor quite a pfew inpfirmities. The company is one of the world's largest research-based pharmaceuticals firms, producing medicines for ailments in fields including cardiovascular health, metabolism, oncology, immunology, and neurology. Its top prescription products include cholesterol-lowering Lipitor, pain management drugs Celebrex and Lyrica, pneumonia vaccine Prevnar, and erectile dysfunction treatment Viagra, as well as arthritis drug Enbrel, antibiotic Zyvox, and high-blood-pressure therapy Norvasc. Consumer health products include such leading brands as Advil, Centrum, and Robitussin. Pfizer and Allergan called off their $160 billion merger in 2016, citing tax reasons.