Exhibit 10.23
SOMAXON PHARMACEUTICALS, INC.
AMENDMENT NO. 1 TO CONSULTING AGREEMENT
     Reference is made to the Consulting Agreement (the “Agreement”) dated
August 25, 2003 by and between Somaxon Pharmaceuticals, Inc. (the “Company”) and
Terry Cobb (the “Consultant”). All capitalized terms used herein and not
otherwise defined shall have the meanings assigned to such terms in the
Agreement.
     Whereas, the parties desire to amend certain terms of the Agreement in
accordance with the terms hereof (this “Amendment”).
     Now Therefore, for good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged by the parties, the parties hereto,
intending to be legally bound, agree as follows:

1.   Section 3.a. of the Agreement shall be deleted in its entirety and replaced
by the following:

  a.   As compensation for the Services to be rendered pursuant to this
Agreement from and after September 23, 2005, the Company shall pay to Consultant
the sum of $10,000.00 per month, to be paid monthly on the last calendar day of
each month. Compensation for Consultant’s services rendered during the first and
last months shall be calculated on a pro-rata basis.

2.   Except for the matters set forth in this Amendment, all other terms of the
Agreement shall remain unchanged and in full force and effect.

     In Witness Whereof, the parties hereto have duly executed this Amendment as
of March 13, 2006.

                          CONSULTANT       SOMAXON PHARMACEUTICALS, INC.    
 
                   
 
  /s/ Terrell A. Cobb       By:   /s/ Kenneth M. Cohen    
 
                   
 
  Terrell A. Cobb           Name: Kenneth M. Cohen    
 
              Title: President and Chief Executive Officer