July 8, 2019 / Modified jul 8, 2019 2:39 p.m.

UA Study: Some medications from Mexico not what the doctor ordered

A team of doctoral students found that many of the drugs fell below guidelines for weight and content.

Mexico meds VIEW LARGER Study authors (from left) Rebecca Smith, Andrea Miller and Nicole Woods
University of Arizona via Fronteras Desk

Located just across the Mexico border from Yuma, Los Algodones is a favorite spot for busloads of Americans to buy cheap medications.

A new study by University of Arizona pharmaceutical doctoral students examines whether they're getting what they bargain for.

Miller and fellow fourth-year PharmD students Nicole Woods, Rebecca Smith and Ernest Vallorz spent more than a year on the analysis, which served as their senior research project.

Based on surveys of more than 400 "medical tourists," the student selected five medications, listed below with their common brand names in parentheses:

  • Metformin (Glucophage, Glumetza, Riomet): a diabetes medicine.
  • Sildenafil (Viagra, Revatio): used to treat erectile dysfunction or pulmonary arterial hypertension.
  • Hydrochlorothiazide (Microzide): a diuretic used to treat high blood pressure and other diseases.
  • Apixaban (Eliquis): an anticoagulant (blood thinner) used to lower the risk of stroke.
  • Ibuprofen (Advil, Motrin): a common pain medication and nonsteroidal anti-inflammatory drug.

After analyzing five lots of each drug, the team found that many, particularly the anti-diabetic drug metformin, fell below United States Pharmacopeia (USP) guidelines for uniform weight and contents.

Lead author Andrea Miller described one extreme example in which two "generic" lots of apixaban, also known by the trade name Eliquis, contained none of the purported blood thinner. Apixaban is not currently available as a generic.

"Eliquis is literally prescribed to prevent strokes and to prevent blood clots, and so it really can be a life-or-death medication for people," said Miller.

Miller also recalled one lot of ibuprofen that was actually acetaminophen (Tylenol). Acetaminophen has strict dosing limits to avoid liver damage and eventual liver failure; it is also sometimes prescribed with ibuprofen.

"It's totally safe to take ibuprofen and acetaminophen together. But if you're taking acetaminophen with more acetaminophen that you think is ibuprofen, that's where we would really start to worry," she said.

Limited to one day and one town, the study supports no clinically significant conclusions, only a reiteration of some ancient advice: Let the buyer beware.

Arizona Science Desk
This story is from the Arizona Science Desk, a collaborative of the state's public radio stations, including NPR 89.1. Read more from the Arizona Science Desk.
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