Final answer:
Drugs are administered with food or taken on an empty stomach for reasons related to absorption and gastric irritation.
Step-by-step explanation:
The reason why some drugs are administered with food and others are taken on an empty stomach is to increase drug absorption and reduce gastric irritation. Certain drugs are better absorbed when taken with food because the presence of food can enhance their dissolution and absorption in the gastrointestinal tract. This can increase the bioavailability of the drug, meaning more of the drug is absorbed into the bloodstream and can exert its therapeutic effects.
On the other hand, some drugs are taken on an empty stomach to minimize drug interactions with food and reduce the risk of delays in drug absorption caused by the presence of food. Additionally, certain drugs may cause gastric irritation and can be better tolerated when taken on an empty stomach to reduce gastrointestinal side effects.