How did lipitor's revenue change after patent expiry?

How much did Lipitor’s revenue fall after patent expiry?

Lipitor’s patent expired in 2011. After that point, sales declined quickly as generic versions entered the market and competed on price.

A widely cited example of the decline is that Lipitor revenue dropped from about $10.3 billion in 2011 to about $5.6 billion in 2012 (a large year-over-year decrease following the expiry). [1]

What drove the drop—generics, pricing pressure, or both?

The steep post-expiry decline was driven mainly by generics taking market share and forcing lower prices. Once generic atorvastatin became available at lower cost, many insurers and buyers switched away from the brand, shrinking both volume and net sales. [1]

Is the decline measured across calendar years or around the exact expiry date?

Reported revenue figures are typically compared by calendar year in financial reporting. Patent expiry occurred in 2011, so the most visible impact often shows up in subsequent annual results (for example, the drop from 2011 to 2012). [1]

Did Pfizer or competitors affect the numbers differently than typical generic entry?

The core driver was generic competition for atorvastatin itself. In practice, the size and timing of the revenue hit tends to reflect how fast generics capture prescriptions and how aggressively pricing shifts in the first months after launch, but the cited revenue change after 2011 aligns with the standard pattern of major-brand revenue erosion post-expiry. [1]

Sources

[1] https://www.investopedia.com/articles/investing/031116/lipitor-and-its-generic-counterpart-what-happened-2011.asp