I was in Cancun last month and all I can say is DO NOT buy it at a human type pharmacia. The prices were pretty close all over town from what I could see. There is a veterinary supply place on Tulum road or street or whatever it is but I never made it to there. That was the place all of the little shitty gift shops said to go. Their was a drug dealer on the street that said he could get it for me, also.
Hope it helps.
Hard
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