Hi triggertravel,
Seems that your initial, very focussed inquiry has now expanded to general prevention & treatment issues.
If you are interested in this, I have a rather detailed article on the topic in the upcoming Apr '02 issue of "Undercurrent"
http://www.undercurrent.org/.
In the meantime, you could read this from my March '00 "Ask RSD" column:
"1. "Do I need to worry about "La Turista"/"Montezuma's Revenge" in Cozumel?" Rich T., Clark, NJ.
Most travelers to Coz report no problem with diarrhea. If concerned, the first step is watching what you drink. Major hotels and restaurants use purified tap water and ice--if in doubt, ask. Many supply bottled water free, and it can be purchased almost anywhere--domestics are the best buy. For extra care, brush teeth/rinse toothbrushes with it. Bottled beverages are generally very safe, but avoid unpasteurized products. Lime or alcoholic spirits may make drinks tastier and more fun, but don't count on them for protection.
Watch what you eat: (1) avoid or work your way up to greasy, fatty and spicy foods, and items you are not used to; (2) eat only fruits and vegetables which have been peeled/ thoroughly washed, and best to stick with the well cooked; (3) things like steak tartare, ceviche and raw shellfish can be inviting trouble; and (4) pass on street vendors and places that appear unhygienic.
If you are susceptible to traveler's diarrhea, starting Pepto-Bismol several days before and throughout the trip can be quite helpful, although this compound may not be well tolerated by some (e.g., those who do not tolerate aspirin), should not used with certain other drugs, and is not intended for long term use.
Many physicians caution individuals against taking antibiotics preventively without a sound reason. If your diarrhea is caused by something other than a microorganism, or by one which is not targeted by or resistant to the antibiotic being taken, the drug simply make things worse. Antibiotics used to prevent and treat some types of diarrhea include Septra, Bactrim, Vibramycin, and Cipro. These are not medications to be used without physician consultation, even if some can be purchased in Mexico without a prescription. They can cause a severe or fatal allergic reaction, and some can cause sensitivity to the sun, sometimes extreme; special precautions need to be taken when using them.
If you are stricken, some experts recommend seeking medical attention if the diarrhea lasts more than two days, or is accompanied by fever, headache or bloody stool. Pepto-Bismol is also used for the treatment of diarrhea, although under a more aggressive regimen. Along with the antibiotics mentioned above, other medications given for the control of symptoms include Lomotil (prescription only in the US), and the over the counter product, Imodium, although they can cause complications in those with serious infections, and may even prolong the course of the illness while controlling some of the features. Prescription antidiarrheals are also not to be used without physician consultation.
Diarrhea by its very nature results in fluid loss, drugs like Lomotil and Imodium can be drying. Plus, many manufacturers recommend that water be taken liberally while on antibiotics. If you get ill, drink plenty of water & sports drinks, even more if taking medication.
It is a good idea to hold off on diving until your more troubling signs & symptoms have passed, and, if you are taking medications, until you can assess what side effects, if any, you are going to experience.
There is no reason to fear diarrhea on Coz given common sense measures. If you take any medications, understand their adverse effects and carefully follow directions. Should you be stricken on Coz, there is a clinic well versed in treating the disorder--your hotel can direct you."
Hopefully you found this informative.
DocVikingo