Proton Pump Inhibitors

Overview :

There are five drugs in this class: esomeprazole (Nexium), lansoprazole (Prevacid), omeprazole (Prilosec), pantoprazole (Protonix), and rabeprazole (Aciphex). They act in a similar manner, and their cautions and adverse effects are similar.

The products are generally formulated as entericcoated granules. Absorption does not start until the granules have left the stomach and reached the intestine, so the onset of action is delayed about an hour, subject to gastric emptying time. Since they act slowly, proton pump inhibitors are not a suitable alternative to antacids which have a rapid effect.

Although these drugs are eliminated from the body relatively quickly, usually within 90 minutes of absorption, they all work for over 24 hours after a dose. This is because the factor that determines duration of action is how long it takes the body to replace the H+, K(+)-ATPase. There is some build up over time. For example, a single dose of lansoprazole reduces stomach acid by 71%, but after a week of regular dosing, the acid reduction rises to 80%.

For treatment of recurrent ulcers, the proton pump inhibitors are part of combination therapy that uses an antibiotic (occasionally two antibiotics) and proton pump inhibitor. There are a number of regimens, and while they may vary in the selection of specific drugs, or even types of drugs used, usually they include a proton pump inhibitor. The cure rates are all within similar ranges for these regimens.