Question

Why are cimetidine and ranitidine better antacids than sodium hydrogen carbonate or magnesium or aluminium hydroxide?

Answer 1

Hint:The substances which neutralize the excess of acid and raise the PH to an appropriate level in the stomach are called antacids. The most common antacids are weak bases.

Complete step by step answer:

Since the overproduction of hydrochloric acid in the stomach causes irritation and pain and in severe cases, ulcers are produced in the stomach. So, to neutralize the excess acid produced in the stomach antacids are used which are also weak bases. Examples of antacids are sodium bicarbonate, magnesium hydroxide, or aluminium hydroxide gel, and aluminium phosphate. The treatment with these salts is temporary as it controls only symptoms and not the causes.
As the acidity in severe cases is life-threatening and can only be treated by removing the affected part of the stomach. A breakthrough in the treatment of hyperacidity came through the discovery that histamine stimulates the secretion of pepsin and hydrochloric acid. Therefore, the drug cimetidine or Tagamet and ranitidine were designed to prevent the interaction of histamine with the receptors in the stomach wall. As a result, less hydrochloric acid is released and the cause of hyperacidity is controlled or cured.
Hence we can say cimetidine and ranitidine are better antacids than sodium hydrogen carbonate or magnesium or aluminium hydroxide because they control the root cause of acid in the stomach.
Hence the correct answer is option D.

Additional information: The importance of cimetidine was so much that it remains the largest selling drug in the world until ranitidine was discovered.

Note:
Recently, omeprazole and lansoprazole have also been used as antacids. They also prevent the formation of excess hydrochloric acid in the stomach.