An Overview of Antacids

When the extra secretion of acid takes place in the stomach, it causes on-off pain, bloating sensation, low appetite and many other health-related problems. Overproduction of acids can even lead to critical diseases like the formation of stomach ulcers. So, how to control the acids?

Antacids are prescribed to people who suffer from acidity problems. In the year 1970, acidity treatment was started using antacids. In the following content, you will get more familiar with: what are antacids, what do antacids do, antacid medicines, etc.

Let us begin.

What is an Antacid Medicine?

The category of medicines that neutralises stomach acids are known as antacids. These tablets contain certain ingredients like calcium, sodium bicarbonate, aluminium and magnesium which acts like alkalis or bases to oppose acid in stomach and make pH neutral.

pH refers to the evaluation of hydrogen ion concentration in any solution, and it shows how alkaline or acidic those solutions are. The pH scale has lower limit one and upper limit 14. If the pH of a solution is seven, it is neutral, if more than seven it is alkaline and lesser than seven is acidic. Typically, pH of gastric acid is between the range of 1.5 and 3.5.

The Following Table Depicts the Commonly Used Antacids

Antacid Ingredient


Neutralising Power

Sodium bicarbonate



Magnesium hydroxide



Aluminum hydroxide



Calcium carbonate


Very high

Now that you have understood what an antacid tablet is, let us move further with antacid components.

Components of Antacid Medicines

Sodium Bicarbonate [ NaHCO₃ ]: It is a short-acting and weak antacid. Though I u's a harmless household remedy, the content of sodium present in it is disadvantageous. Doctors generally do not recommend "baking soda" or "bicarb", but it is a commonly used ingredient of several patent medicines. Bicarbonate holds an effervescent trait that illustrates commercial existence of pain-killer/antacid blend like Bromo-SeltzerTM and Alka-SeltzerTM. This component reacts with hydrochloric acid (HCl) of stomach to yield carbon dioxide (CO2) that gets absorbed fast but occasionally evokes a satisfying burp.

Systemic alkalosis (imbalance of human body's pH level) may be a result of bicarbonate overuse. People, who have high blood pressure and are prescribed not to have much sodium, should avoid bicarbonate.

Magnesium Hydroxide [ Mg(OH)2 ]: It is popularly called as milk of magnesia. Similar to magnesium sulphate and magnesium citrate, magnesium hydroxide is also a good laxative. Manufacturers mix this component with aluminium hydroxide to control the diarrhoea effect it causes. However, the price of medicine increases and aluminium hydroxide decreases the benefit of antacid.

Magnesium hydroxide itself does not get absorbed in intestine. Instead, when it interacts with the stomach acid; it releases magnesium chloride which is absorbed. Mg (magnesium) holds a lot of functions in cells of the human body. However, it has a harmful effect if levels of Mg increase in blood. Also, people with renal failure must avoid magnesium.

Aluminium Hydroxide [ Al(OH)3 ]: In comparison to the previous component, this one is weak and has slow action on human body. Moreover, neutralising power varies among commercial medicines.

Aluminium may safeguard the lining of stomach from harmful effects of irritants like alcohol. Al(OH)3 has other applications as well. It helps in binding phosphate in gut lumen to yield aluminium phosphate which is insoluble. This product is useful for kidney failure when serum phosphate goes high abnormally and for people who have a tendency of forming kidney stones that contain phosphate.

Prolonged use of this component may cause brain damage, metabolic bone conditions like osteoporosis and osteomalacia, and risk of causing fractures, particularly in malnourished people.

Calcium Carbonate [ CaCO3 ]: Chalk is the common name for calcium carbonate and is the most abundantly available antacid. It has the capability to neutralise acid entirely in stomach. However, it may not be the right choice for daily use.

One major side effect of  antacids is that gastric acid secretion may rebound after taking this medicine. Commercial antacid tablets that contain calcium have Titralac TM and TumsTM, and its dosage should not go above 3 g each day.

Besides the primary components, there are some extra components, such as:

  • Peppermint flavouring

  • Antiflatulent

  • Alginic acid

How do Antacids Work?

All antacid tablets have the capability to work in two manners.

  1. Antacids cover the oesophagus surface with a preventive layer against acids of stomach.

  2. They release a gel on the surface of stomach that helps to stop the leakage of acid to the food pipe. This way, it can prevent heartburn symptoms.

Next, let us discuss what are antacids used for?

Use of Antacids

Apart from heartburn, the primary uses of antacids are to provide relief from Gastroesophageal Reflux Disease (GERD), indigestion or dyspepsia, belching, bloating, feeling of discomfort in gut or stomach. By counteracting stomach acids, these medicines can help to cure the feeling of burning in throat or chest due to acid reflux, bitter taste in mouth, a sensation of pain while lying down, regurgitation and continuing dry cough. These acid medicines can be merged with other tablets as well to provide relief from heartburn symptoms.

What is GERD and Acid Reflux?

Acid reflux takes place when stomach contents reach up in oesophagus. It is also termed as gastroesophageal reflux or acid regurgitation. If you experience acid reflux symptoms more than two times in a week, you may be suffering from GERD.

Moreover, GERD can sometimes lead to difficulty in swallowing food and also breathing conditions like asthma.

Did You Know?

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) suggest that 20% of US citizens are affected with GERD, and if it is not treated, can cause serious issues.

When a person is diagnosed with GERD, medical practitioners usually advise making changes in eating habits and lifestyle. Besides antacids, doctors also prescribe two different classes of medicines like H2 receptor blockers and proton pump inhibitors.

Some Widely Used H2 Receptor Blockers are:

  • Nizatidine (Axid)

  • Cimetidine (Tagamet HB and Tagamet)

  • Famotidine (Pepcid AC and Pepcid)

Note: The selling of Tagamet across the world was most massive until ranitidine (Zantac) was introduced.

Some Commonly Used Proton Pump Inhibitors are:

  • Lansoprazole (Prevacid 24 HR)

  • Omeprazole (Prilosec)

  • Pantoprazole sodium (Protonix)

  • Rabeprazole sodium (Aciphex)

Other than the Earlier Mentioned Disorders, Few Antacids can Help to Cure Unrelated Health Problems Like:

  • Deficiency of calcium.

  • High blood phosphate levels.

  • Formation of stones in the kidney.

  • Deficiency of magnesium.

By now, you must have got familiar with what is the use of antacid. However, you must keep it in mind that all medicines come with side effects. The following section is related to the side effects of antacids.

Antacids Side Effects

The ingredients present in antacid tablets are responsible for the unwanted side effects. However, few product combinations show side effects that invalidate each other. For example, magnesium can cause diarrhoea and aluminium can cause constipation, so a tablet containing these two components, have a more neutral effect on bowel.

Generally, if you take antacids as directed by a physician or the way mentioned on the tablet strip, you will experience comparatively fewer effects. Over usage of the medicines along with prolonged usage without prescription, they may have side effects.

Following are some common side effects of antacids which you must keep in mind:

  1. Constipation

  2. Aluminium toxicity

  3. Low levels of blood phosphate

  4. Osteomalacia

  5. Kidney stones

  6. Nausea

  7. Alkalosis

  8. High magnesium level in blood

  9. Increase in blood pressure, etc.

Furthermore, if high doses of antacids are taken for an extended period, it can cause a problem termed as an acid rebound. This condition occurs when stomach releases more acids after consumption of drinks and food.

Sometimes people take medicines for acidity issues on their own. However, you must always take drugs after consultation with a doctor as only they will understand which is the antacid medicine that can cure your problem.

Do it Yourself

1. What is the other name for magnesium hydroxide?

a) sugar b) milk of magnesia c) chalk d) baking soda

2. Is the following sentence true or false?

Osteoporosis is a side effect of antacids.

3. Classify the following medicines like antacids, proton pump inhibitors and H2 receptor blockers.

a) Sodium bicarbonate b) Nizatidine c) Aluminium hydroxide d) Omeprazole

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FAQ (Frequently Asked Questions)

1. What are the Antacid Medicines?

Ans. The antacid medicines like Aluminium Hydroxide, Magnesium Hydroxide, Pepto-Bismol, Gaviscon, Gelusil, etc. helps to neutralise extra acid formation in stomach.

2. When Should Someone Take Antacids?

Ans. Generally, medicines should be taken after food, but it is always recommended to ask the physician for the correct dosage and time.

3. What is the Meaning of Antacid?

Ans. Antacids are medicines which counteract the acids in stomach to relieve the symptoms like sour stomach, heartburn, stomach upset, pain, etc. Few antacids also consist of simethicone that helps in releasing gas from the body.

4. What is Anti Acid?

Ans. Anti acids are similar to antacids, which have the same property to fight acidity.