Drug Interactions-3

Absorption nay be altered due to alteration in any of the four mechanisms
1. Gastrointestinal motility and gastric emptying rate.
2. Gastrointestinal flora.
3. pH of the GIT.
4. Free drug available in GIT.

Alteration in Gastric motility and Gastric emptying rate:
GI absorption is slowed by drugs that inhibit gastric emptying such as atropine
or opiates or accelerated by drugs such as metoclopramide

Alteration of pH:
Antacids, Sodium bicarbonate, Calcium carbonate may alter the pH of the GIT
and thus alter the absorption of drugs whose absorption is dependant on pH such
as Iron products, aspirin, NSAIDS.

Alteration of Gastro intestinal Flora:
Some antibiotics destroy the gastro intestinal flora and thus prevent the absorption
of some other drugs.

Availability of free drug:
Calcium and iron form insoluble complex with tetracycline and retards its absorption

ABSORPTION INTERACTIONS

Complexation and Absorption:

Alteration of GI pH:

Alteration of Gut Motility :

Alteration of microbial flora :

Malabsorption Syndrome:

In my coming bolgs I will like to discuss more on Distibution, Metabolism,Excretion,
Pharmacokinetic interactions and some guidelines to prevent Drug interactions.......