Prilosec vs. Nexium comparison
Prilosec (omeprazole) and Nexium (esomeprazole) are used to treat
gastroesophageal reflux disease (GERD) and other digestive conditions related to
overproduction of stomach acid. These drugs are part of a family of medications
called proton pump inhibitors or PPIs, which hinder gastric glands from making
acid at a cellular level.
Other PPIs include:
Omeprazole and esomeprazole are nearly identical on a chemical level, so they
have all the same side effects and drug interactions. Esomeprazole is the newer
medication. Researchers started with omeprazole, and then tinkered with how the
molecules were stuck together. As a result, they came up with esomeprazole,
which is usually much more potent than omeprazole, despite the slight chemical
Side effects of these drugs are usually mild, but they can include diarrhea,
nausea, vomiting, headaches and others. Doctors also try to avoid prescribing
PPIs long-term because they interfere with the body’s ability to absorb vitamin
B12 and cause lower magnesium levels. Long-term users can develop skeletal
problems and be more prone to heart attacks.
What are Prilosec and Nexium?
Prilosec and Nexium are proton pump inhibitors or proton pump antagonists.
Proton pumps are the
mechanisms that squirt out components of hydrochloric acid (hydrogen and
chloride ions) into the stomach from
the gastric glands to
be used for digestion.
The proton pump is a sort of valve made of a molecule of protein on certain
stomach cell (parietal cell) membranes. The precise name of the proton pump
protein is adenosine triphosphatase or ATPase. It’s called a “proton pump”
because it actively grabs positively charged atoms of hydrogen from within the
cell and “pumps” them into the stomach cavity by switching them with potassium
molecules. In the ducts of the gastric glands, the hydrogen ions combine with
chloride ions to form hydrochloric acid, which is necessary to digest food.
Chloride ions are also secreted by parietal cells, which suck them up from the
bloodstream and secrete them through a different channel than the
It’s important for the proton pump to shoot the hydrogen out of the parietal
cell before it turns into acid. Gastrointestinal lining is the only tissue in the body
built to handle potentially lethal hydrochloric acid. If the parietal cell manufactured
hydrochloric acid inside itself — as cells do when they make most other
compounds — the acid would kill the cell, digesting it from the inside out
instead of digesting the pork chop you just ate.
The molecules of omeprazole and esomeprazole plug up the “valve” of
the proton pump, meaning it can’t release hydrogen ions into the stomach, which
results in less acid.
Esomeprazole — the newer, more advanced of the two — is an isomer of
omeprazole. This means it’s got all the same types and numbers of atoms in the
molecule, they’re just stuck together in a different way, so Prilosec and Nexium
are nearly identical on a chemical level. That slight structural change makes a difference,
though. If we continue thinking of the proton pump as a valve, Nexium forms a tighter seal when it plugs up the proton pump. The result is
that even a double dose of Prilosec isn’t as effective at acid control as a
single dose of Nexium, according to a 2002 study.
PPIs are more effective than older H2R antagonists/blockers like famotidine. H2R
blockers plug up a protein on parietal cell outer membranes that is set up to
receive the messenger chemical called histamine, which is used to initiate all
sorts of processes throughout the body. When histamine is
inserted into the receptor protein — called the H2 receptor — it begins the process of
acid production. PPIs — which stop acid production in the final step rather
than the first step — tend to do a better job at acid control, partly because
people quickly develop a tolerance for H2R antagonists after repeated dosing,
according to a 2014 study.
Antacids like Pepto Bismol (bismuth), Rolaids, or Tums (calcium carbonate)
work completely differently than either PPIs or H2R antagonists. Antacids mix
with and neutralize stomach acid after it’s already in the stomach cavity. They
work fast, but don’t last long.
What are the uses for Prilosec and Nexium?
Omeprazole an esomeprazole are used for treating acid-induced inflammation and ulcers of the stomach and duodenum; gastroesophageal reflux disease (GERD); erosive esophagitis, heartburn; prevention of upper gastrointestinal bleeding in critically ill patients; and Zollinger-Ellison Syndrome. It also is used in combination with antibiotics for eradicating H. pylori infection of the stomach. Over-the counter (OTC) omeprazole is used for treatment of frequent heartburn.
Medically Reviewed by a Doctor on 3/30/2017
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