Pharmacology · chapter 31 · Hyperacidity and Antiulcer Drugs
Antacids
The 14 things this section of the textbook says that you are most likely to be asked about — quoted word for word, not retold. Then 6 practice questions with the reasoning.
Key points
Short-term use only
The goals of antacid therapy are to alleviate symptoms of heartburn and indigestion such as pain, as well as stomach spasms. Antacids are recommended for short-term use only.
Sodium bicarbonate and fluid retention
Because it contains sodium, it may not be suitable for individuals on sodium-restricted diets or those with conditions that cause fluid retention, such as heart failure and chronic kidney disease.
Calcium carbonate is also a supplement
Calcium carbonate is a fast-acting oral antacid that efficiently neutralizes gastric acids, offering relief from heartburn and associated symptoms. It also serves as a calcium supplement, beneficial for conditions such as osteoporosis and hypocalcemia.
Chew or swallow whole
Chewable tablets must be chewed thoroughly before swallowing. Sustained-released capsules should be swallowed whole and never chewed.
Timing of calcium carbonate
When taken as an antacid, calcium carbonate is administered 1 hour after meals and at bedtime.
Why antacids are combined
It is often used in combination with other antacids. These combination antacids provide both acid-neutralizing properties and relief from potential constipation.
Magnesium hydroxide can cause diarrhea
When taken in larger quantities or more frequently than recommended, magnesium hydroxide can act as a mild laxative, potentially resulting in diarrhea.
Separate from other medications
May decrease absorption of all medications; recommend taking 1 hour before or 2 hours after other medications.
Constipation, diarrhea and rebound acid
Typical adverse effects of antacids include constipation (particularly those containing aluminum or calcium when used in large amounts or for extended periods of time), diarrhea (specifically antacids containing magnesium, which have a laxative effect), rebound hyperacidity (when the antacid wears off and the stomach produces additional acid), kidney stones (particularly from antacids containing calcium, as some kidney stones are caused by calcium oxalate), and gas and bloating.
Electrolyte imbalances
When used excessively or for prolonged periods of time, antacids can potentially lead to electrolyte imbalances. The specific electrolyte imbalance that can result from antacid use depends on the types of minerals they contain.
Signs of hypermagnesemia
Symptoms may include muscle weakness, nausea, vomiting, diarrhea, low blood pressure, and in severe cases, cardiac arrhythmias and respiratory distress.
Kidney disease and heart failure
Individuals with kidney disease or heart failure should use antacids containing magnesium, aluminum, or sodium cautiously, as these may impact kidney function.
Watch I&O with sodium bicarbonate
Monitor fluid intake and urine output (I Os) for urinary retention and edema with sodium bicarbonate.
Report signs of a severe reaction
Reports effects such as muscle twitching, tetany, edema, or bone pain to the health care provider as these may be symptoms of a severe adverse reaction.
Terms to know
- Antacids
- Antacids are a class of over-the-counter medications that are used to neutralize or reduce gastric hyperacidity.
- Sodium bicarbonate
- Sodium bicarbonate is an alkaline substance that neutralizes excess stomach acid.
- Aluminum hydroxide
- Aluminum hydroxide is a formulation of aluminum hydrochloride and water.
Practice questions
Stuck on select-all-that-apply? How to take them one option at a time.
The graded version needs JavaScript. Every question is below anyway, with the answer and why.
Every question here, with the answer
A client with heart failure asks which antacid to buy for heartburn and mentions sodium bicarbonate. What should the nurse explain?
- Sodium bicarbonate is the safest choice in heart failure.
- Its sodium content may not suit people with conditions that cause fluid retention, such as heart failure.
- It has no effect on fluid balance.
- It is safe as long as it is taken with meals.
Answer: Its sodium content may not suit people with conditions that cause fluid retention, such as heart failure.
Sodium bicarbonate contains sodium and may not be suitable for sodium-restricted diets or conditions that cause fluid retention like heart failure. Timing with meals does not remove the sodium load.
A client takes calcium carbonate chewable tablets and several other daily medications. What should the nurse teach?
- Take the antacid only on an empty stomach in the morning.
- Take the antacid 1 hour before or 2 hours after other medications.
- Take the antacid together with the other medications.
- Swallow the chewable tablets whole.
Answer: Take the antacid 1 hour before or 2 hours after other medications.
Calcium carbonate may decrease absorption of all medications, so it is taken 1 hour before or 2 hours after them. Chewable tablets must be chewed thoroughly, and as an antacid it is given after meals and at bedtime.
A client with chronic kidney disease has been taking a magnesium-containing antacid for months. Which findings suggest hypermagnesemia? Select all that apply.
- Low blood pressure
- Excessive thirst and dry mouth
- Constipation
- Diarrhea
- Muscle weakness
Answer: Low blood pressure, Diarrhea, Muscle weakness
Hypermagnesemia may cause muscle weakness, nausea, vomiting, diarrhea and low blood pressure. Thirst and dry mouth point to hypernatremia, and constipation is linked to aluminum or calcium antacids.
A client says they have been taking an antacid every day for a month. What is the nurse's best response?
- Switch between two antacids at the same time for better effect.
- That is fine as long as symptoms improve.
- Double the dose so you can stop sooner.
- Antacids are meant for short-term use, and should not be used for more than 2 weeks.
Answer: Antacids are meant for short-term use, and should not be used for more than 2 weeks.
Antacids are recommended for short-term use only, and clients should not use them for more than 2 weeks or take two different antacids at the same time. Longer use raises the risk of electrolyte imbalances.
The nurse is teaching a client about taking antacids. Which instructions should be included? Select all that apply.
- Shake suspensions well before taking.
- Keep using them for several months.
- Drink 8 ounces of fluid after taking antacids.
- Chew oral tablets thoroughly before swallowing.
- Take two different antacids together for faster relief.
Answer: Shake suspensions well before taking., Drink 8 ounces of fluid after taking antacids., Chew oral tablets thoroughly before swallowing.
Clients should chew tablets thoroughly, shake suspensions well, and drink 8 ounces of fluid afterward. They should not take two types of antacids at the same time or use them for more than 2 weeks.
A client who takes large doses of calcium carbonate reports hard, infrequent stools. How should the nurse interpret this?
- It is a sign of hypermagnesemia.
- It is an adverse effect of calcium-containing antacids.
- It means the antacid is not working.
- It is caused by rebound hyperacidity.
Answer: It is an adverse effect of calcium-containing antacids.
Constipation is a typical adverse effect of antacids containing aluminum or calcium, especially in large amounts or over time. Magnesium antacids tend to cause diarrhea instead, and rebound hyperacidity is extra acid, not constipation.
Where every quote comes from
Section 31.1 Antacids of Pharmacology for Nurses by Tina Barbour-Taylor, Leah Mueller (Sabato), Donna Paris, Dorie Weaver, OpenStax, 2024. Read the whole section free at openstax.org.
The textbook is licensed under CC BY-NC-SA 4.0. This page quotes it word for word and adds the headings, the order and the practice questions; references to the book's figures and stray spaces left by its formatting are removed. The page is shared under the same licence. Nothing here is sold.