GI DRUGS
ANTI Acid
MOA: Basic compounds used to neutralize stomach acid
DRUGS Salts of aluminum, magnesium, calcium, and/or sodium
Many antacid preparations also contain the antiflatulent (antigas) drug
simethicone.
Many aluminum- and calcium-based formulations also include magnesium, which
not only contributes to the acid-neutralizing capacity but also counteracts the
constipating effects of aluminum and calcium.
Calcium antacids
Calcium antacids may lead to the development of kidney stones and
increased gastric acid secretion.
Antacids containing magnesium must be avoided in patients with renal
failure.
Sodium bicarbonate is a highly soluble antacid form with a quick onset but
short duration of action.
Mechanism of Action: Do not prevent the overproduction of acid but instead help
to neutralize acid secretions, Promote gastric mucosal defense mechanisms
Stimulate secretion of:
o Mucus: protective barrier against HCl
o Bicarbonate: helps buffer acidic properties of HCl
o Prostaglandins: prevent activation of proton pump
o Antacids: Indications
Acute relief of symptoms associated with peptic ulcer, gastritis, gastric
hyperacidity, and heartburn
Antacids: Contraindications, Known allergy to a specific drug product,
Severe renal failure or electrolyte disturbances: potential toxic accumulation
of electrolytes in the antacids themselves
GI obstruction: antacids may stimulate GI motility when they are
undesirable because of the presence of an obstructive process requiring
surgical intervention
Antacids: Aluminum Salts
Causes constipation
, Often used with magnesium to counteract constipation. do not when mixed
with magnesium if patient has renal disease.
Often recommended for patients with renal disease (more easily excreted)
Examples
o Aluminum carbonate: Basaljel
o Hydroxide salt: AlternaGEL
o Combination products (aluminum and magnesium): Gaviscon,
Maalox, Mylanta, Di-Gel
o Antacids: Magnesium Salts
Commonly cause diarrhea; usually used with other drugs to counteract this
effect.
Dangerous when used with renal failure; the failing kidney cannot excrete
extra magnesium, resulting in accumulation.
Examples
o Hydroxide salt: magnesium hydroxide (Milk of Magnesia)
o Carbonate salt: Gaviscon (also a combination product)
o Combination products such as Maalox, Mylanta (aluminum and
magnesium)
Antacids: Calcium Salts
Many forms but carbonate is most common
May cause constipation, kidney stones
Also not recommended for patients with renal disease—may accumulate to
toxic levels
Long duration of acid action—may cause increased gastric acid secretion
(hyperacidity rebound)
Often advertised as an extra source of dietary calcium
o Example: Tums (calcium carbonate)
Antacids: Sodium Bicarbonate
Highly soluble
Buffers the acidic properties of HCl
Quick onset but short duration
May cause metabolic alkalosis
Sodium content may cause problems in patients with heart failure (HF),
hypertension, or renal insufficiency.
Aluminum- and sodium-based antacids are recommended for patients with
renal compromise because they are more easily excreted. Both calcium- and
ANTI Acid
MOA: Basic compounds used to neutralize stomach acid
DRUGS Salts of aluminum, magnesium, calcium, and/or sodium
Many antacid preparations also contain the antiflatulent (antigas) drug
simethicone.
Many aluminum- and calcium-based formulations also include magnesium, which
not only contributes to the acid-neutralizing capacity but also counteracts the
constipating effects of aluminum and calcium.
Calcium antacids
Calcium antacids may lead to the development of kidney stones and
increased gastric acid secretion.
Antacids containing magnesium must be avoided in patients with renal
failure.
Sodium bicarbonate is a highly soluble antacid form with a quick onset but
short duration of action.
Mechanism of Action: Do not prevent the overproduction of acid but instead help
to neutralize acid secretions, Promote gastric mucosal defense mechanisms
Stimulate secretion of:
o Mucus: protective barrier against HCl
o Bicarbonate: helps buffer acidic properties of HCl
o Prostaglandins: prevent activation of proton pump
o Antacids: Indications
Acute relief of symptoms associated with peptic ulcer, gastritis, gastric
hyperacidity, and heartburn
Antacids: Contraindications, Known allergy to a specific drug product,
Severe renal failure or electrolyte disturbances: potential toxic accumulation
of electrolytes in the antacids themselves
GI obstruction: antacids may stimulate GI motility when they are
undesirable because of the presence of an obstructive process requiring
surgical intervention
Antacids: Aluminum Salts
Causes constipation
, Often used with magnesium to counteract constipation. do not when mixed
with magnesium if patient has renal disease.
Often recommended for patients with renal disease (more easily excreted)
Examples
o Aluminum carbonate: Basaljel
o Hydroxide salt: AlternaGEL
o Combination products (aluminum and magnesium): Gaviscon,
Maalox, Mylanta, Di-Gel
o Antacids: Magnesium Salts
Commonly cause diarrhea; usually used with other drugs to counteract this
effect.
Dangerous when used with renal failure; the failing kidney cannot excrete
extra magnesium, resulting in accumulation.
Examples
o Hydroxide salt: magnesium hydroxide (Milk of Magnesia)
o Carbonate salt: Gaviscon (also a combination product)
o Combination products such as Maalox, Mylanta (aluminum and
magnesium)
Antacids: Calcium Salts
Many forms but carbonate is most common
May cause constipation, kidney stones
Also not recommended for patients with renal disease—may accumulate to
toxic levels
Long duration of acid action—may cause increased gastric acid secretion
(hyperacidity rebound)
Often advertised as an extra source of dietary calcium
o Example: Tums (calcium carbonate)
Antacids: Sodium Bicarbonate
Highly soluble
Buffers the acidic properties of HCl
Quick onset but short duration
May cause metabolic alkalosis
Sodium content may cause problems in patients with heart failure (HF),
hypertension, or renal insufficiency.
Aluminum- and sodium-based antacids are recommended for patients with
renal compromise because they are more easily excreted. Both calcium- and
