I have a long-standing chronic constipation problem. Recently my primary physician prescribed Prevacid for me. I'm not sure why, as I do not suffer from ulcers or gastroesophageal reflux. However, I do see that this medication is also prescribed for Zollinger-Ellison syndrome. Can you tell me what this is?

F.

Chronic constipation is a common medical complaint for which many different medications, both prescription and over-the-counter, are used with variable success. Often different patients respond differently to the various medications available.

Lansoprazole (Prevacid) is an acid-suppressive medication of the proton-pump inhibitor (PPI) class. Another commonly used PPI medication is omeprazole (Prilosec). These drugs are the most potent inhibitors of stomach acid secretion available, and are extremely effective in acid-related diseases such as gastric and duodenal ulcers and gastroesophageal reflux disease (GERD). One of the more common side effects of PPI therapy is diarrhea. Although in studies, this symptom was found in less than 5 percent of patients, doctors definitely find patients who develop this symptom on these medications. This is probably the reason that Prevacid was given to you in treating your chronic constipation, although the drug is not approved or labeled for the treatment of constipation.

As for your second question, Zollinger-Ellison syndrome is a rare disease characterized by a tumor (most commonly in the pancreas) that secretes large quantities of a hormone known as gastrin. Gastrin is normally produced by the stomach, and its function is to prompt the stomach to secrete acid in response to a meal. In a patient with Zollinger-Ellison, the excessive amounts of gastrin stimulate the stomach to overproduce acid, leading to ulcers in the duodenum. Although the ideal therapy for the condition is surgical removal of the tumor, in some patients this is not feasible, either because the tumor's exact location can not pinpointed or because it is an advanced-stage tumor. In those cases, PPI therapy may be used to prevent the excess acid production caused by high levels of gastrin.