Page 101 - Interactive Theoritical Notes of Bioharmaceutics and pharamcokinetics.docx compressed

PharmD clinical pharmacy program Level 3, Semester 2 Biopharmaceutics & Pharmacokinetics (PT608(

6. Effect of Food on Drug Absorption from GIT

(a)- Improving drug absorption:

Lipid-soluble drugs such as griseofulvin are better absorbed when given with food

containing a high-fat content.

Propranolol plasma concentrations are higher after food than in fasted subjects.
(b)- Decreasing the drug absorption:

The absorption of some antibiotics, such as penicillin and tetracycline, is decreased

with food.

Complexation of Tetracycline with components in the diet forms non-absorable
complexes with calcium and iron.

Thus, it is advised that patients do not take products containing calcium or iron, such
as milk, iron preparations or indigestion remedies, at the same time of day as the

tetracycline.
(c)- Decreasing the irritation to GI mucosa

Some drugs, such as erythromycin, iron salts, aspirin, and nonsteroidal anti-

inflammatory agents (NSAIDs), are irritating to the GI mucosa and are given with

food to reduce this irritation.

(d)- Alteration of pH:

Food tends to increase stomach pH by acting as a buffer.

This is liable to decrease the rate of dissolution and subsequent absorption of a weakly

basic drug and increase that of a weakly acidic one.

100