Somaxon Pharmaceuticals, Inc. that Somaxon and Procter & Gamble have entered into a co-promotion agreement for Silenor (doxepin), a newly-approved treatment for insomnia characterized by difficulty with sleep maintenance, reported by MarketWatch.com. Under the terms of the agreement, Somaxon and Procter & Gamble will co-promote Silenor with sales representatives in the U.S. market. Procter & Gamble''s professional health care sales force will promote Silenor to targeted primary care and other high-prescribing physicians. Somaxon''s focus will be on specialists and other top-decile physicians who treat insomnia. In addition, Procter & Gamble will promote Silenor to targeted pharmacies and will provide supplemental managed care support services for Silenor. Somaxon has also granted Procter & Gamble a right of first negotiation relating to rights to develop and market Silenor as an over-the-counter medication in the U.S.