Few conditions prohibit the use of proton pump inhibitors (PPIs) in patients. Patients who have a history of hypersensitivity to PPIs should not take these medications. In addition, patients who have severe liver disease should only use these medications with extra caution.

A recent study shows that taking PPIs for a year or longer can markedly increase the risk of hip fractures in people over the age of 50. Therefore, it is often recommended that individuals age 50 or older who take PPIs for an extended period also take supplemental calcium and vitamin D to strengthen the bones.
Because of their acid blocking activity, PPIs have the potential to cause small bowel bacterial overgrowth, which may result in bad breath.

Proton pump inhibitors (PPIs) are generally considered to cause relatively few side effects in people who use them. Side effects that do occur are similar to those associated with use of H2 blockers. The most common include headache, diarrhea, stomach or abdominal pain, flatulence, dry mouth, constipation, nausea and skin rash. Recently there have been conflicting reports about whether the use of PPIs is associated with Clostridium difficile (a type of bacterium) infections in patients. There have also been concerns that use of PPIs may increase a patient’s risk of cancer of the stomach or esophagus. However, recent research suggests that the medication is not associated with elevated cancer risk.