Gastric Obstruction

Question.

214. Presence of food might be expected to interfere with drug absorption by slowing gastric emptying, or by altering the degree of ionisation of the drug in the stomach. Which of the following statements is not correct example:

1. Absorption of digoxin is delayed by the presence of food.

2. Concurrent food intake may severely reduce the rate of absorption of phenytoin.

3. Presence of food enhances the absorption of hydrochlorthiazide.

4. Anitimalarial drug halofantrine is more extensively absorbed if taken with food.

Answer

3. Presence of food enhances the absorption of hydrochlorthiazide.

Reference

KDT 5^th Edition Pages 372(Phenytoin), 748 (Halofantriene) and 4^th Edition Pages 492(digoxin), 384(Phenytoin), 565(Thiazides),

Halofantriene – Park, Katsung ,Harrison 15^th Edition Table 414-4

Goodman Gilman 9^th Edition Page 957

CMDT 2003 Page 441

Quality

Thinker

Status

New

QTDF

??

Discussion

Presence of Food generally dilutes the drug and retards absorption. Certain drugs form complexes with certain constituents of the food. For example Tetracycline complexes with Calcium and more over food delays Gastric emptying. Thus most drugs are better absorbed if taken in empty stomach. But few drugs which are irritant are better given with food.

Explanation

1. Absorption of digoxin as well as digitoxin is delayed by the presence of food.

2. Concurrent food intake may severely reduce the rate of absorption of phenytoin.

3. Presence of food has no effect on the absorption of hydrochlorthiazide.

4. Anitimalarial drug halofantrine is more extensively absorbed if taken with fatty food (Katsung).

Comments

A question for which one needs knowledge of Pharmacokinetics (often ignored)

Tips

Make a note of drugs that are increased with food (other than Halofantriene)