The Collaborative International Dictionary of English v.0.48:

Amnesic \Am*ne"sic\, a. (Med.)
   1.

   1. Of or pertaining to amnesia. "Amnesic or coordinate
      defects." --Quian. AS
      [1913 Webster]

   2. Suffering from amnesia; same as amnesiac.
      [PJC]

WordNet (r) 3.0 (2006):

amnesic
    adj 1: of or relating to or caused by amnesia [syn: amnestic,
           amnesic]
    2: suffering from a partial loss of memory [syn: amnesic,
       amnesiac]
    n 1: a person suffering from amnesia [syn: amnesic,
         amnesiac]