Drugs manufactured by pharmaceutical manufacturing companies are used to treat patients worldwide.
The largest manufacturers of these products are Pfizer and Roche.
Pfizer produces some of the most widely used medicines.
The two other major players in the market are Novartis and AstraZeneca.
Both are also the major producers of pharmaceuticals.
The most widely studied drugs in the US are the painkillers OxyContin and Vicodin, and the antidepressants Paxil and Celexa.
All drugs are manufactured in the United States and the world.
These are the top five pharmaceutical companies.