Originally Posted by JDiver

Be aware, there are "pirate" (counterfeit) drugs available in Mexico, and conditions vary considerably in storage - temperatures can get quite warm in non-air conditioned farmacias. Be sure to check the ingredient list - many medications vary in naming, and some sold in Mexico with the same name as US (or other) have the principal ingredients, but may be compounded with other active ingredients you may not want.

While a number of medications can be obtained without prescriptions (e.g. antibiotics,) some medications, particularly anything that could be considered a stimulant, narcotic or depressants - are more controlled than in the USA or Canada, and do necessitate a doctor's prescription (which should be carried with one.) Some medications sold in Mexico may be of any US or European list - one common and popular anti-diarrheal was sold years after they were prohibited in Europe, Japan and the US because one of the potential side effects was blindness (now that's a serious stopper...)

Mexico regulates the maximum prices of medications - "Precio máximo al público" should be on the printed on the box, with the maximum allowable price in pesos. Most pharmacies also have a book similar to the US PDR (Physicians Desk Reference") available, but of course, it is in Castilian, and may have different pharmaceutical or generic names (we do that in English as well - "acetaminophen" in the US is "paracetamol" nearly everywhere else, including Argentina.) Some medications available in the US, Canada, Europe may just not be available in Mexico, either entirely, or in strengths you may be looking to buy; and a number of medications have a different appearance (the paracetamol I purchased last week in Buenos Aires, for example, was a much larger tablet than the comparable strength acetaminophen in the US,) or may be packaged differently - such as in individually tearable packets dispensed in strips from a box.

As well, there are different kinds of farmacias: only "de Primera Clase" have a licensed pharmacist in attendance at all times. Other points of note - many pharmacies have someone on staff who is capable of giving injections - but be sure they are using disposables, as you may not be able to evaluate the sanitary conditions of their autoclave or other sterilization method. Finally, you can still get your meds compounded by hand in some farmacias - but it may be compounded by an ayudante, or totally unlicensed and sometimes unsupervised "assistant."

How do I know this? A number of my family members were physicians in Mexico, and my first jobs after school / summers were translating, selling and working the counters, compounding meds for people and animals (including small doses of "sleeping pills" for drugging parrots to be smuggled into the USA,) unpacking and stocking, etc. at Farmacia Zapata - where medical advice was dispensed and injections given as well (but not by me.) Fuhgeddaboudit - the statute of limitations, if there was any law against it anyway, is long, long expired... ¡Salud!