The February 2009 FDA listing shows

    63668  products, including the same or similar products from different
    	   manufacturers/packagers/labellers,

    81386  dosage forms for these products,

   155338  package configurations in which they are provided.

    Some of the items listed are over-the-counter products commonly prescribed
    by physicians.
    

    There are lots of versions of amoxicillin (an antibiotic of the penecillin
    family) in the list.  Depending on the condition being treated, the dose
    for adult humans is typically 750 - 1750 mg/day, taken in two or three
    doses.

    Amoxapine is an antidepressant.  The usual starting dose for adult humans
    is 50 mg two or three times daily, rising to 300 mg/day if the patient
    tolerates the drug well.  Doses up to 600 mg/day (not all at once)
    may be used.

    The mistaken prescription would seem to have given an initial dose that
    exceeds the maximum for individuals who have been using the drug for some
    time and are known to tolerate it well.

    Interestingly, Amoxapine is probably the only drug that would come up
    as a completion for Amoxicillin.  "Amoxil" is a synonym for amoxicillin
    but it doesn't seem to be used for labelling products.

    Sources:  US FDA, RxList