Proton Pump Inhibitors

One of the most widely sold (according to Wikipedia) medications in the world is the proton pump inhibitor, commonly sold under trade names such as Prilosec or Prevacid.  Its basic effect is to reduce the amount of acid produced by the stomach, to alleviate chronic heartburn caused by stress, diet, or in my case, random unexplained Act of Deity.  Seriously, my doc couldn't figure it out at all.

Anyway, that's what it does, but how does it work?  What is a proton pump, and why should it be inhibited?

Proton pumps are not exactly mechanical pumps, the way your heart is a mechanical (although also biological) pump.  Instead, they are a specific class of proteins found in cell membranes that move protons chemically from one side of the membrane to the other.  Since protons carry a positive electric charge, this creates an electric potential that typically can be used as a reservoir of energy-- sort of like a biochemical capacitor.  This stored energy can be used by the body's cells for a variety of functions.

When you take a PPI, it specifically targets a class of cells in your gastric system, the ones responsible for producing gastric acid.  In this particular case, the protons moved by the pumps are not being used to store energy-- instead, they are being used to provide the extra H⁺ ions that are used to create acids (those of you with some high-school physics no doubt already realize that an H⁺ ion is in fact just a proton, and those of you with freshman chemistry may recall that acids are sometimes defined as proton donors, i.e. substances with extra protons).  So with these proton pumps "inhibited," not nearly as much acid is formed, taking production back down to more or less normal levels (since heartburn is typically caused by overproduction in the first place).

And voila!  Life goes back to more or less normal.  Side effects are pretty minimal (occasional headache or fatigue are common), although there are some minor risks with long-term use-- hypomagnesemia (an easily treatable deficiency of magnesium), or minor risk of vitamin B₁₂ deficiency (not really an issue for anyone on a typical American diet).