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Spokane, Washington  Est. May 19, 1883

People’s Pharmacy: How much Pepto Bismol prevents traveler’s diarrhea?

A study published in JAMA reported that two Pepto Bismol tablets four times a day were 65% effective at preventing traveler’s diarrhea.  (Courtesy of
By Joe Graedon, M.S.,</p><p>and Teresa Graedon, Ph.D. King Features Syndicate

Q. Now that COVID-19 is becoming less of a problem, my husband and I are looking forward to a long-delayed trip to Mexico. I know that a daily dose of Pepto Bismol is recommended when traveling to certain countries, but I can’t recall the correct dosage. Can you help?

A. A study published in JAMA (March 13, 1987) reported that two Pepto Bismol tablets four times a day were 65% effective at preventing traveler’s diarrhea. One tablet four times daily was 40% effective. A meta-analysis of 14 clinical trials confirms that bismuth subsalicylate (Pepto Bismol) triples your chance of avoiding traveler’s diarrhea (Digestive Diseases and Sciences, July).

Most of the authors of this analysis work for Procter & Gamble, maker of Pepto Bismol. You’ll still need to be cautious about what you eat and drink. Keep in mind that Pepto Bismol will probably turn your stool black. That looks alarming, but if you are well, it should not be dangerous.

Q. You’ve written about “authorized generics” in the past. Greenstone used to make one for the antidepressant sertraline, but they’ve discontinued manufacturing it. Is there an authorized generic sertraline available at all? I’m not sure if the brand name (Zoloft) is available, but it’s astronomically cost-prohibitive anyway. Any help or info would be much appreciated.

A. Greenstone has been merged into a larger company called Viatris, which also absorbed Mylan and the Upjohn division of Pfizer. Previously, Greenstone manufactured many authorized generic versions of Pfizer brand-name drugs.

For authorized generic drugs, the brand-name maker licenses the product and supplies the precise recipe or even the pills themselves. Consequently, an authorized generic is extremely similar or possibly identical to the brand name. Greenstone stopped supplying sertraline in October. You are not the only person who misses the authorized generic. Another reader wrote:

“I haven’t felt well since I was switched from Zoloft to generic sertraline. My insurance will not pay for Zoloft, and it is too expensive for me. The only generic that worked for me was Pfizer’s own generic for Zoloft: Greenstone. But the pharmacist cannot find any. It makes no sense to take cheaper medication if it isn’t effective.”

Brand-name Zoloft could cost as much as $450 for a month’s supply. However, there might be another option. lists several Canadian online pharmacies that accept U.S. prescriptions. The cost for brand-name Zoloft runs from about $25 to $85 a month.

You can learn more about authorized generic drugs and lower-cost brand products from legitimate Canadian pharmacies in our eGuide to Saving Money on Medicines. This online resource can be found under the Health eGuides tab at

Q. I am curious about the thyroid status of the readers who have written to you about their bleeding fingertips. I was diagnosed as hypothyroid at age 10. I’m 75 now, so I have more than 60 years of observation, experience and research.

My prescribed dosage of thyroid meds over the years has varied. Without enough thyroid medicine, my fingertips split and bleed in the winter months. When I have enough thyroid med, that doesn’t happen.

A. Others have reported similar experiences. Dry, cracking skin is a red flag for hypothyroidism.

In their column, Joe and Teresa Graedon answer letters from readers. Write to them in care of King Features, 628 Virginia Drive, Orlando, FL 32803, or email them via their website They are the authors of “Top Screwups Doctors Make and How to Avoid Them.”