The high dose of Protonix — not irritable bowel syndrome — is likely the cause of your diarrhea. One of the most serious side effects of proton pump inhibitors (PPI) is C. difficile diarrhea. I’ve seen this in many older patients, and the Food and Drug Administration recently issued a safety alert about these drugs and diarrhea that doesn’t go away. The PPI actually lowers the acidity of the stomach so much that the C. difficile bacteria — normally kept at bay by the acid in your stomach — proliferate out of control.

The PPI also may be causing your anemia. With the change in pH in your stomach, acid-sensitive drugs and nutrients like iron and calcium can just pass through your system unabsorbed.

I recommend that you ask your doctor to test your stool for the presence of C. difficile bacteria. If that’s positive, you will need antibiotic therapy immediately.

I’d also suggest discussing whether to discontinue the PPI. If you don’t, in fact, have GERD, all the drugs and supplements you’re taking may be unnecessary.

Getting you off the PPI after so long must be done very slowly. Under your doctor’s guidance, you’ll gradually drop the dose in 20-milligram increments, with 10 to 15 days between each taper, until you are completely off the drug. In some people the process takes even longer.

But if you continue to have severe reflux problems, you and your doctor may want to consider the use of an H2 blocker such as ranitidine (75mg every 12 hours) on an as-needed basis. Some of my patients have reported success with the home remedy of apple cider vinegar and honey (one tablespoon of each in a glass of water), taken throughout the day, along with melatonin at bedtime.

Finally, about your chest pains, you may want to consult with another cardiologist, just to be sure all is well. And if you’re again given a clean bill of health, anxiety may well be the cause of your pain, so ask your regular doctor about treating your anxiety. I’d recommend an SSRI/SNRI such as venlafaxine ER for this purpose.

Also of interest: Unexpected side effects from prescription drugs.

"Ask the Pharmacist" is written by Armon B. Neel Jr., PharmD, CGP, in collaboration with journalist Bill Hogan. They are coauthors of Are Your Prescriptions Killing You?, to be published this year by Atria Books.