And here is a key point: A prescription from a Mexican doctor is no longer acceptable. The price difference is so great that some Americans travel to Mexico to take advantage of the savings. How do you choose which one is better for you? These are the drugs that are often cheaper than those in the U. Even then, there are restrictions. · Mexico is the largest market for erectile dysfunction in the developing world, with about $ million in sales every year. That is why Pfizer has chosen the country for . It can be difficult to compare the cost of medications in Mexico () to those in the United States () due to co-pay differences. At a Mexican pharmacy, you . The agency has also issued alerts about contaminated, counterfeit batches of the anemia drug Procrit, bogus Viagra, sham contraceptive patches that don’t do .