The price difference is so great that some Americans travel to Mexico to take advantage of the savings. How can you be sure of that when you choose a Mexican pharmacy for Cialis? Summary There are limits to bringing prescriptions purchased at a Mexican pharmacy into the United States. Cialis is a brand-name prescription medication. The medication should be in its original container with a doctor’s instructions printed on the bottle, in English, and generally containing no more than a three month supply.Published on October 12, Medically reviewed by Femi Aremu, PharmD Table of Contents View All Understanding ED What Is Cialis? How Cialis Works Efficacy Dosing . But buying Cialis in Mexico is an option to and the prices are similar. Choosing a Mexican pharmacy for Cialis may also have other advantages depending on your situation. . BraunS / Getty Images Are Prescriptions From Mexican Pharmacies Legal? You can bring prescription medications approved by the Food and Drug Administration .