Over production of acid in the stomach causes irritation and pain. In severe cases, ulcers are developed in the stomach. Until 1970, only treatment for acidity was administration of antacids, such as sodium hydrogencarbonate or a mixture of aluminium and magnesium hydroxide. However, excessive hydrogencarbonate can make the stomach alkaline and trigger the production of even more acid. Metal hydroxides are better alternatives because of being insoluble, these do not increase the pH above neutrality. These treatments control only symptoms, and not the cause. Therefore, with these metal salts, the patients cannot be treated easily. In advanced stages, ulcers become life threatening and its only treatment is removal of the affected part of the stomach.

Which drug was was designed to prevent the interaction of histamine with the receptors present in the stomach wall?

Cimetidine

The correct answer is option 2. Cimetidine.

The drug designed to prevent the interaction of histamine with the receptors present in the stomach wall is Cimetidine. Cimetidine is a medication classified as an \(H_2\) receptor antagonist, also known as an \(H_2\) blocker. It works by blocking the action of histamine at \(H_2\) receptors in the stomach lining, thereby reducing the production of stomach acid. By preventing histamine from binding to its receptors, cimetidine decreases the secretion of gastric acid, which helps alleviate symptoms of heartburn, acid reflux, ulcers, and gastroesophageal reflux disease (GERD).

The other options are:

Zantac: Zantac is the brand name for ranitidine, another \(H_2\) receptor antagonist similar to cimetidine. Like cimetidine, ranitidine also blocks histamine receptors in the stomach lining, reducing stomach acid production.

Omeprazole and Lansoprazole: Omeprazole and lansoprazole belong to a different class of medications known as proton pump inhibitors (PPIs). Unlike \(H_2\) blockers, PPIs work by inhibiting the proton pump in the stomach's cells, thereby blocking the final step of acid production. They are not designed to prevent the interaction of histamine with its receptors.

Cimetidine is the drug specifically designed to prevent the interaction of histamine with the receptors present in the stomach wall. As an \(H_2\) receptor antagonist, it blocks histamine receptors, reducing stomach acid production and providing relief from acid-related conditions.

The structure of Cimetidine is :