Proton pump inhibitors (PPIs) are a group of medications used primarily to decrease the amount of stomach acid secreted. Commonly used PPIs include Prilosec (omeprazole), Prevacid (lansoprazole), Nexium (esomeprazole), Protonix (pantoprazole) and Aciphex (rabreprazole). Zegerid is a combination of two medications: omeprazole and sodium bicarbonate. These medications all have similar mechanisms of action on decreasing stomach acid production. Dosing varies, depending on whether the goal of treatment is healing or prevention. PPIs are often prescribed for prophylaxis against developing ulcers in patients who are at risk.
Proton Pump Inhibitor (PPI) Function
Proton pump inhibitors function by decreasing the output of stomach acid. PPIs block the gastric proton pumps that are responsible for the secretion of stomach acid or hydrochloric acid into the stomach. The result is less total stomach acid.
H. Pylori
H. Pylori, a bacteria, has been implicated in causing many gastrointestinal ulcers. Along with antibiotics, a proton pump inhibitor has been proven to help eradicate H. Pylori, thereby reducing the risk of future ulcer and treating any current ulcer. Clarithromycin and amoxicillin are commonly the antibiotics given along with a PPI for this "triple therapy." By eradicating the H. Pylori, the risk of developing a future ulcer is reduced.
Ulcers
Ulcers from nonsteroidal anti-inflammatory (NSAID) and steroid medications can be prevented with PPIs. Patients can be placed on a PPI to help reduce the amount of stomach acid that is able to erode the stomach and/or duodenum.
Stress-induced ulcers occur during physiologic times of stress. Many intensive care unit patients develop stress ulcers. Because of the higher incidence of stress ulcers in sick patients, many hospitalized patients are placed on a PPI as prophylaxis to decrease the total amount of stomach acid and therefore prevent the erosion of the stomach and/or duodenum.
Zollinger-Ellison Syndrome is a condition of excessive acid secretion by the stomach due to a tumor located usually in the pancreas or duodenum. The tumor, called a gastrinoma, produces increased levels of gastrin, one of the hormones that signals the stomach to produce more acid. PPIs work by helping to control the total amount of stomach acid by blocking the production of acid. The end effect is to decrease the occurrence of ulcers and prevent the formation of ulcers; but PPIs do not treat the underlying tumor.
Dosing and Formulation
Proton pump inhibitors come orally or as intravenous preparations. Intravenous preparations are used in patients who are in the hospital and who are unable to take anything by mouth. Oral proton pump inhibitors are the method of choice for most indications for proton pump inhibitors. Oral formulations can be purchased as either over the counter or by prescription. All PPIs come as a capsule or pill form. Some PPIs such as omeprazole come as an oral liquid formulation as well.
Some PPIs such as omeprazole are sold over the counter and also as generic. Over-the-counter medications do not require a prescription. Generic medications typically cost less than brand name medications, however they contain the same active ingredients, but the processing may be different. Generic medications may not be available in the same doses. For example, Prilosec is available in 10mg, 20mg and 40mg, but generic omeprazole may only be available in 10mg and 20mg. Taking two 20mg generic omeprazole tables makes for a 40 mg dose. The ulcer prophylaxis dose of a PPI depends upon the specific PPI. The prophylaxis dose is less total milligrams than the treatment dose.
Side Effects
Proton pump inhibitors are generally well tolerated. Allergic reactions can occur as with any other medication. Due to the lack of stomach acid, patients on PPIs are more at risk for vitamin B12 deficiency due to less absorption. PPIs also increase the risk of Clostridium difficile infection which can cause diarrhea. A painful rash known as Steven-Johnson can also occur. Common reactions to PPIs include headache, diarrhea and abdominal pain.
References
- Epocrates: Prilosec
- "Current Medical Diagnosis and Treatment"; Dr. Stephen McPhee and Dr. Maxine Papadakis; 2007
- "Lippincott's Illustrated Reviews: Pharmacology (3rd ed)"; Dr. Richard Howland and Dr. Mary Mycek; 2006
