DRUG DRUG INTERACTION

what is a DDI?

It is when either PD or PK of a drug is affected by the other

What are some mechanisms of drug interaction at absorption site?

1. Drug binding in the GIT (adsorption, chelation, complication, resin binding)
2. Alteration of Gi motility
3. Alteration of GI pH
4. Effects of intestinal flora
5. Effects of drug metabolism within the GI wall and liver during fist pass

What causes adsorption, complication and resin binding?

Adsoprtion: Charcoal, antacids, kaolin-pectin
Complication: Iron, antacid
Resin binding: cholestyramine, colestipol

What causes alteration of GI motility?

increase GI motility: laxatives, metoclopramide
decerases GI motility: anticholinergics, opiates, Al(OH)3

What increases the GI pH?

H2RA
PPI

What decreases the intestinal flora?

Antibiotics