Difference Between Nexium and Omeprazole

Prilosec and Nexium are both coming under the drug class category of proton pump inhibitors. Proton pumps are situated in mitochondrial membranes, which mean they are in almost all cells. The importance of these drugs is that they selectively inhibit proton pumps in the stomach lining. The mechanism of action is to selectively inhibit H+/K+ ATPase enzyme in gastric parietal cells. Although Nexium and Prilosec are from the same drug class, differences between the two could be found.


Omeprazole is also known by the tradenames Zegerid and Prilosec. Omeprazole is a proton pump inhibitor. This drug is prescribed to treat complications related to excessive acid secretion in the stomach such as damage to the esophagus and gastroesophageal reflux disease (GERD). At times, it is also prescribed along with antibiotics to treat stomach ulcers arising due to Helicobacter pylori infections. This drug cannot render immediate relief from heartburn.

Directions to use: The Omeprazole tablet should be taken 30 minutes before meals. The pill should be swallowed as a whole without chewing because it may damage the coating which is designed to protect the stomach. Granular suspension should only be taken with apple juice. Sometimes the granular suspension is delivered through nasogastric feeding tube. Omeprazole should not be taken if one is allergic to the drug. It should not be taken while a person is taking other benzimidazole drugs. If a person is taking HIV AIDS medicine, ampicillin, blood thinner, water pills, iron tablets, or diabetes medicine, it is important to seek medical advice before taking Prilosec/Omeprazole.

Harmful effects and side effects of Omeprazole: There are a number of harmful effects of the drug. Animal studies have shown chronic usage may cause stomach cancers although it is not confirmed with humans up to the date. Tendency to increase bone fracture in the hips, wrists, and spine is also found through clinical studies. Long term usage has shown to decrease the Vitamin B12 absorption and, therefore, cause B12 deficiency. Apart from all the harmful effects, the drug also has various side effects associated. Uneven and fast heart rate, muscle weakness, diarrhea, coughing and choking, headache, and troubles in memory are some of the serious side effects. In addition, weight change, stomach pain, and insomnia are also experienced.


Nexium is the tradename of the drug Esomeprazole. It is also a proton pump inhibitor to similar to Omeprazole. The mechanism of action, the applications, and the side effects of Nexium are quite similar to Omeprazole, but there is a difference when it comes to availability of these drugs. Esomeprazole is readily available compared to omeprazole.

What is the difference between Omeprazole and Nexium?

• Chemical composition of the two drugs is different. Omeprazole: (RS)-5-methoxy-2-((4-methoxy-3,5-dimethylpyridin-2-yl) methylsulfinyl)-1H-benzo[d]imidazole, and Esomeprazole: (S)-5-methoxy-2-[(4-methoxy-3,5-dimethylpyridin-2-yl) methylsulfinyl]-3H-benzoimidazole.

• Esomeprazole/Nexium is readily available than Omeprazole, and as a result, it has more extended side effects, as well.

• Esomeprazole can eradicate H.pylori than Omeprazole does.

• It is claimed that Esomeprazole is more efficient than Omeprazole, but it has not been proven yet.


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