The Collaborative International Dictionary of English v.0.48:

medico \medico\ n.
   1. a student in medical school.

   Syn: medical student.
        [WordNet 1.5]

   2. A licensed medical practitioner. [slang]

   Syn: doctor, doc, physician, MD, Dr.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

medico
    n 1: a student in medical school [syn: medical student,
         medico]
    2: a licensed medical practitioner; "I felt so bad I went to see
       my doctor" [syn: doctor, doc, physician, MD, Dr.,
       medico]

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "medico":
   Doctor of Medicine, GP, MD, Md, allopath, allopathist,
   attending physician, coroner, country doctor, croaker, doc, doctor,
   family doctor, general practitioner, house physician, intern,
   leech, medical, medical attendant, medical examiner, medical man,
   medical practitioner, physician, physician in ordinary, resident,
   resident physician, sawbones