2006 New York Code - When Substitution Is Required.

 
    § 6816-a. When  substitution  is  required.    1.  A  pharmacist shall
  substitute a less expensive drug  product  containing  the  same  active
  ingredients,  dosage  form  and strength as the drug product prescribed,
  ordered or demanded, provided that the following conditions are met:
    (a) The prescription is written on a form which meets the requirements
  of subdivision six of section sixty-eight hundred ten  of  this  article
  and  the  prescriber  does  not prohibit substitution, or in the case of
  oral  prescriptions,  the  prescriber  must  expressly   state   whether
  substitution  is  to  be  permitted or prohibited. Any oral prescription
  that does not include such an express statement shall not be filled; and
    (b) The substituted drug product is contained  in  the  list  of  drug
  products  established  pursuant  to  paragraph (o) of subdivision one of
  section two hundred six of the public health law; and
    (c) The  pharmacist  shall  indicate  on  the  label  affixed  to  the
  immediate  container in which the drug is sold or dispensed the name and
  strength of the drug product and its manufacturer unless the  prescriber
  specifically  states  otherwise.  The  pharmacist  shall  record  on the
  prescription form the brand name or the name of the manufacturer of  the
  drug product dispensed.
    2.  In the event a patient chooses to have a prescription filled by an
  out of state dispenser, the laws of that state shall prevail.