Provigil was launchd in the UK in March 1998 and it is used to promote wakefulness in patients with narcolepsy, a condition characterized by excessive daytime sleepiness.
The first sign of parallel imports being sold into the UK was in November 2001, and though a trickle at first it grew to a peak of over 120 price list inclusions each month by September 2006, which meant that pharmacists and dispensing doctors had lots of opportunity to buy the imported version of the UK brand.
During this period there was tight control over the prices of parallel imports and although they decreased somewhat between 2001 and 2012 they would tightly constrained, suggesting that the number of sources the importers were able to collect from was very limited. In July 2011 the patent expired in the UK and generics were launched. It took awhile for this to affect the pricing, but by early 2013 PI prices had become a lot more erratic and the pre-existing decline in the number of Provigil price lists continued apace.
By early 2016 the number of price lists had declined to just a handful each month, and the pricing of the parallel import was highly variable. The last time the PI was seen was in May 2022, and since then the generic has completely dominated the market.