I would say that Motrin was the first blockbuster product for The Upjohn Company in the modern era. The chemical name for Motrin is Ibuprofen. It is an NSAID (Nonsteroidal Anti-Inflammatory Drug) that is used primarily to treat fever, mild to moderate pain (including pain relief after surgery), painful menstruation, osteoarthritis, dental pain, headaches, and pain from kidney stones. It may be that just about everyone in a first or second world country has by now used Ibuprofen at some point in their lives.

Ibuprofen was discovered in 1961 in Nottingham, UK, by Stewart Adams and John Nicholson while working at Boots the Chemists. In 1969 it was first sold in the UK using the product name Brufen. Upjohn bought the rights to sell it in the USA and other countries from Boots. They got a 300 mg and 400 mg coated tablet approved by FDA and on sale in the USA in 1974, using the product name Motrin. The large sales volume of Motrin was a pleasant surprise to the company. It was initally made in Building 41, Portage but moved to the Upjohn Puerto Rico plant, then called the Upjohn Manufacturing Company-M, and that plant ran at full-capacity.

A 600 mg tablet strength was approved in 1979 and an 800 mg strength in 1985. A Motrin 800 mg SR (sustained-release) tablet was introduced in 1988. In 1984, Motrin accounted for 40% of Upjohn earnings. Also in 1984, a 200 mg over-the-counter (OTC) strength was introduced using the name Nuprin. It was manufactured by Upjohn but sold by Bristol-Myers. No prescription was needed any longer. In 1989, Motrin IB was a 200 mg strength introduced and sold OTC directly by Upjohn.

As Motrin patents expired and generic Ibuprofen products proliferated, the profitability shrunk. By the end of the Upjohn era in 1995, only the Motrin 800 mg SR tablet was left in the product catalog. Such is the life of a blockbuster!

Here's a 1974 Motrin 400 mg Tablets advertisement for medical professionals, saved by the University of Wisconsin Libraries.

Wikipedia Article on Ibuprofen