LESSON 2
ANTACIDS AND DIGESTANTS
Section I. ANTACIDS
2-1.
INTRODUCTION
Many of the patients you will see at the outpatient pharmacy window will be there
to receive antacid preparations. You will usually see these patients every several
months because they will return to obtain more antacids. Thus, one can see that many
of the patients who take antacid preparations will be taking them for many years. You
must be familiar with the antacid preparations so that you can adequately serve these
patients.
2-2.
GENERAL CONSIDERATIONS FOR ANTACIDS
a. Definition. Antacids are drugs which neutralize part of the hydrochloric acid
in the stomach.
b. Indications for the Use of Antacids. Antacids are indicated in ulcer
therapy, minor stomach irritations, and other conditions depending on the type of
antacid prescribed.
c. Factors Considered When an Antacid is Prescribed. Before a patient is
prescribed a particular antacid preparation, the prescriber must consider the patient's
condition as well as a group of other factors. Some of these factors are listed below:
(1) Gastric acid neutralization. The chief reason for prescribing an antacid
preparation is the neutralization of the hydrochloric acid in the stomach. Antacid
preparations contain one or more drugs which chemically neutralize this hydrochloric
acid. Not all chemicals neutralize the same amount of stomach acid on a weight-by-
weight basis. Therefore, the prescriber must be aware of the active ingredient(s)
present in an antacid preparation and how effectively that preparation is able to
neutralize stomach acid in relation to other antacid preparations.
(2) Effect on systemic pH. Most antacid agents remain in the
gastrointestinal system when they are taken to neutralize stomach acid. However,
some agents (e.g., sodium bicarbonate (NaHCO3)), because of their ability to ionize, are
capable of going into systemic circulation in the bloodstream once they are ingested.
For example, if enough sodium bicarbonate is ingested, the bicarbonate ion (HCO3) can
be systemically absorbed and affect the pH of the blood. This effect is highly
undesirable.
MD0807
2-2