Antacids: Nursing pharmacology

00:00 / 00:00



Mechanism of Action
Gastric acid-neutralizing agent; reacts with excess acid in the stomach, reducing acidity
Route of Administration
PO, enteral
Aluminum hydroxide 
(AlternaGEL, Amphojel, Nephrox)
GI disorders associated with hyperacidityUse with caution in clients with hypertension, heart failure, and low serum phosphate levels
Calcium carbonate 
(Dicarbosil, Rolaids, Titralac, Tums)
Should not be taken with milk products or vitamin D supplements
Calcium carbonate with magnesium hydroxide 
(Mi-Acid Double Strength, Mylanta Supreme, Rolaids, Fast Acting Mylanta)
Calcium component: Hypercalemia and hypercalciuria, severe renal disease, renal calculi, GI bleeding or obstruction and dehydration

Magnesium component: Abdominal pain, nausea & vomiting, diarrhea, fecal impaction, rectal bleeding, colostomy or ileostomy in place

Should not be taken with milk products or vitamin D supplements
(Lowsium, Ron-Acid)
Severe renal disease

Use cautiously in clients with mild renal impairment
Magnesium hydroxide 
(Milk of Magnesia, Pedia-Lax, Almacone)
Abdominal pain, nausea & vomiting, diarrhea, renal impairment, fecal impaction, rectal bleeding, colostomy or ileostomy in place
Magnesium trisilicate and aluminum hydroxide 
(Gaviscon Tablet)
Impaired kidney function, diarrhea, hypophosphatemia, hemorrhoids, intestinal blockage, constipation, aluminum poisoning, chronic diarrhea, chronic heart failure, severe renal impairment, visible water retention, decreased urine production, hypernatremia
Magnesium hydroxide and aluminum hydroxide 
(Mylanta, Mygel, DiGel, Gelusil, Rulox)
Use with caution in clients with hypertension, heart failure
Magnesium hydroxide, aluminum hydroxide, and simethicone
(Almacone, Gelusil, Mag-al Plus, Mi-Acid, Milantex)
GI disorders associated with hyperacidity; antiflatulentImpaired renal function, diarrhea, hypophosphatemia, henorrhoids, intestinal blockage, constipation, aluminum poisoning, chronic diarrhea
Sodium bicarbonate 
GI disorders associated with hyperacidityShould not be used in clients on a sodium-restricted diet
  • All antacids should be administered and taken on a regular schedule
  • Clients should be educated to chew antacids tablets well and follow them with water or milk, if not contraindicated
  • Antacids that come in liquid form need to be shaken before taken
  • If administering an antacid via nasogastric tube (NGT), be sure to flush with water following the medication
  • Use with caution in lactating women
  • Keep out of reach of children
  • Aluminum compounds: can reduce the effects of tetracyclines, warfarin sodium and digoxin
  • Magnesium compounds: magnesium hydroxide is also saline laxative, commonly causes diarrhea when used alone
  • Calcium compounds: can cause acid rebound
  • Sodium compounds: useful for treating acidosis and elevating urinary pH to promote excretion of certain drugs following overdose

High Yield Notes

1 pages


Antacids are acid reducing medications that directly lower the acidity of stomach contents. They are used to treat conditions like gastroesophageal reflux disorder, or GERD, and peptic ulcer disease, or (PUD).

When combined with antiflatulent medications like simethicone, they also help decrease gas production, which provides comfort and relief to clients experiencing gas or bloating. Antacids can be made up of aluminum, magnesium, calcium or sodium compounds.

Common antacid medications include: aluminum hydroxide, aluminum hydroxide and simethicone, magnesium hydroxide, magnesium hydroxide and aluminum hydroxide, magnesium trisilicate and aluminum hydroxide, magaldrate, calcium carbonate, calcium carbonate with magnesium hydroxide, and sodium bicarbonate.

Now when antacids are taken, the medication reacts with gastric acid and results in the production of neutral or low-acidity salts that increase the gastric pH. Additionally, the enzyme pepsin that normally helps digest protein is also inactivated.

The outcomes of these reactions are a decrease in gastric acidity, enhanced mucosal protection and a reduction of the symptoms associated with GI conditions such as GERD and PUD.

Antacids can cause several side effects If they are taken for an extended period of time, they may alter aluminum, calcium, sodium and phosphate levels.

Other general side effects of antacids include belching, constipation, flatulence, diarrhea and gastric distention.


Antacids are medications that neutralize stomach acid. There are three types of antacids: aluminum hydroxide, magnesium carbonate, and calcium carbonate. Each type has its benefits and drawbacks.

Aluminum hydroxide is the most common type of antacid. It's available over-the-counter and is effective at neutralizing stomach acid. However, it can also cause constipation and has been linked to neurotoxicity. Magnesium carbonate is also available over-the-counter and is effective at neutralizing stomach acid. It doesn't cause as many side effects, but it can still cause diarrhea and abdominal pain. Calcium carbonate is another antacid that is available over-the-counter. It's effective at neutralizing stomach acid and can be taken long-term. However, it can cause constipation and gas.


  1. "Pearson Reviews & Rationales: Comprehensive Review for NCLEX-RN, 3rd Edition" Pearson (2018)
  2. "Saunders Comprehensive Review for NCLEX-PN" undefined (1999)
  3. "Physiology, Pepsin" undefined (2021)

Copyright © 2023 Elsevier, its licensors, and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Cookies are used by this site.

USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.