co-promotion agreement in the U.S. (down approximately $320 million in 2013), and Enbrel, reflecting the expiration of the co-promotion term of the collaboration agreement in the U.S. and Canada in October 2013 (down approximately $82 million);

lower revenues from generic atorvastatin (down approximately $145 million in 2013);

lower revenues from Prevnar, due to decreased government purchases (down approximately $84 million in 2013); and lower revenues from Zosyn (down approximately $45 million in 2013),

partially offset by:

the strong performance of certain other biopharmaceutical products, including Lyrica, Celebrex, Xeljanz, Inlyta and Xalkori (up approximately $715 million in 2013).

• in our international markets, revenues from biopharmaceutical products decreased 7% in 2013, compared to 2012. Operationally, revenues decreased 3% in 2013, compared to 2012, reflecting, among other things:

lower revenues for Lipitor and Xalatan/Xalacom (down approximately $1.4 billion in 2013) due to the loss of exclusivity of Lipitor in developed Europe, Japan and Australia, and Xalatan/Xalacom in the majority of European markets and in Australia; lower revenues for Viagra (down approximately $108 million in 2013) primarily due to loss of exclusivity in most major markets in Europe; and lower revenues for Aricept (direct sales) (down approximately $88 million in 2013) due to the loss of exclusivity in certain markets; and

lower Alliance revenues (down approximately $493 million in 2013), primarily due to the loss of exclusivity of Aricept in many major European markets, the return of our rights to Aricept in Japan to Eisai Co., Ltd., and lower revenues for Spiriva in certain European countries, Canada and Australia (where the Spiriva collaboration has terminated),

partially offset by:

higher revenues for Lyrica, and new product growth from Inlyta and Xalkori (collectively, approximately $506 million in 2013).

The unfavorable impact of foreign exchange on international biopharmaceutical revenues of 4% in 2013 also contributed to the decrease in revenues from biopharmaceutical products in our international markets.

During 2013, international revenues from biopharmaceutical products represented 61% of total revenues from biopharmaceutical products, compared to 62% in 2012.

For additional information about operating segment revenues, see the “Analysis of Operating Segment Information” section of this Financial Review.

Revenues—Major Biopharmaceutical Products

The following table provides revenue information for several of our major biopharmaceutical products:

Biopharmaceutical—Selected Product Descriptions

• Lyrica (GIP/GEP) is indicated in the U.S. for three neuropathic pain conditions, fibromyalgia and adjunctive therapy for adult patients with partial onset seizures. In certain countries outside the U.S., indications include neuropathic pain (peripheral and central), fibromyalgia, adjunctive treatment of epilepsy and generalized anxiety disorder. Worldwide operational revenues for Lyrica increased 14% in 2014 compared to 2013. Foreign exchange had a unfavorable impact on worldwide revenues of 2% in 2014, compared to 2013.

In the U.S.,