Difference Between Zantac and Omeprazole


Main Difference

The main difference between Zantac and Omeprazole is that Zantac is less potent in suppressing gastric acid secretion than omeprazole.

Zantac vs. Omeprazole

Zantac is H-2 receptor blocker; on the other hand, Omeprazole is a proton pump inhibitor. Zantac is a brand name, while Omeprazole is a generic term. Zantac contains ranitidine HCl while Omeprazole is found in its S and R isomer forms. Zantac is suitable to treat nocturnal acidity while Omeprazole suppresses acid secretion in 24 hrs equally. Zantac is preferably prescribed for duodenal ulcers; on the other hand, Omeprazole is preferably prescribed for gastric ulcers and Zollinger Ellison syndrome. Zantac is not available in powdered form while Omeprazole is available in powdered form.


Comparison Chart

Zantac is the brand name of H-2 receptor blocker ranitidine.Omeprazole is the generic name of one of the drugs of proton pump inhibitors.
Receptors at Which Drug Acts
Zantac acts on H-2 receptorsOmeprazole acts on proton pumps
Mode of Action
Zantac is mild gastric acid suppressor as compared to omeprazoleOmeprazole is a potent gastric acid suppressor
Protein Binding of Drug
A small percentage of Zantac is protein bound.A large percentage of omeprazole is protein bound.
Available Dosage Forms
Tablets, InjectionsTablets, Capsules, Powders, Parenterals
Therapeutic Uses
Gastric Ulcers
Duodenal Ulcers
Stress Ulcers
Gastric Ulcers
Duodenal Ulcers
Zollinger Elison Syndrome

What is Zantac

Zantac is the brand name of ranitidine, which is H2 receptor antagonist. Zantac suppresses the gastric acid secretions about 70% in 24 hrs. Zantac inhibits basal acid secretion, so it is used to suppress the nocturnal acid secretion. Zantac is used to treat the duodenal ulcers because duodenal ulcers are mostly due to the nocturnal acidity, so it is prescribed at evening times to treat duodenal ulcers. Zantac increases the GI motility, but therapeutic effect due to this ability is still unknown. Zantac is an over the counter drug. Zantac is rapidly absorbed after oral administration, and its peak serum concentration is reached in 1-3 hrs. Zantac is more rapidly absorbed in the presence of food, and its absorption is decreased in the presence of antacid. 10% -35% of the Zantac undergoes metabolism through the liver. Zantac and its metabolites are excreted by the kidney, and the excretion through kidneys are important for the dose adjustment of Zantac in patients having decreased creatinine clearance. Zantac shows minor side effects like headache, diarrhea, drowsiness, muscular pain. Zantac also effects CNS and confuses slurred speech. Zantac is also reported for the blood dyscrasias, including thrombocytopenia. Zantac can cross the placenta and excretes in breast milk. Zantac, unlike other H2 receptor antagonists, interferes less with hepatic metabolism of other drugs. Zantac not only treats gastric and duodenal ulcers but also it prevents the occurrence of stress ulcers.



Zantac enteric-coated tablets and injects.

What is Omeprazole

Omeprazole is the Proton pump inhibitor which are potent suppressors of gastric acid secretions, so omeprazole inhibits the proton pumps. Omeprazole inhibits 80% to 90% of the basal and stimulated secretion of gastric acid. omeprazole is also available in it’s in its S-isomer form esomeprazole. Omeprazole is the racemic mixture of its R and S isomers, and S isomer is eliminated less rapidly than R isomer. Omeprazole- S isomer has increased half-life. Omeprazole, like other proton pump inhibitors, is available in the form of a prodrug, which changes into an active form in the presence of the acidic environment. Omeprazole is degraded in an acidic environment, to address this issue it is available enteric-coated drugs enclosed in gelatin capsules, enteric-coated tablets and powered omeprazole in combination with sodium carbonate. Omeprazole shows less absorption in the presence of food. Omeprazole when reaches to small bowl it is rapidly absorbed. Omeprazole has high protein-bound concentration. Omeprazole is metabolized by the hepatic enzymes. Omeprazole requires 2-5 days of therapy to inhibit 70% of the proton pumps. Omeprazole shows adverse effects like headaches, diarrhea, constipation. Omeprazole, when used for the long periods, it decreases the absorption of vitamin b-12. Omeprazole treats gastric, duodenal ulcers, gastroesophageal reflux disease, and Zollinger Ellison syndrome.


Common brands that contain Omeprazole are Prilosec, Losec, etc.

Key Differences

  1. Zantac is an H-2 receptor antagonist while Omeprazole is proton pump inhibitors.
  2. Zantac does not bind extensively to proteins; on the other hand, Omeprazole is extensively protein-bound drug.
  3. Zantac is available in its active form while Omeprazole is available as a prodrug which becomes active in an acidic environment.


The conclusion of the above discussion is that Zantac and omeprazole both belong to two different drug categories, but both are used to suppress gastric acid secretions.

Janet White

Janet White is a writer and blogger for Difference Wiki since 2015. She has a master's degree in science and medical journalism from Boston University. Apart from work, she enjoys exercising, reading, and spending time with her friends and family. Connect with her on Twitter @Janet__White