Antacids, Proton Pump Inhibitors and Other Stomach Acid Drugs

Antacids are one of the most commonly used over-the-counter (OTC) medication globally. It is easily available in stores other than pharmacies and many substances that may not be classified as drugs can act like antacids. While this is the first choice of treatment for conditions associated with gastric acid secretion, there are several other drugs that may also be used such as proton pump inhibitors (PPIs) among others.

Drugs that lower stomach acid are mainly used for gastritis, peptic ulcers and gastroesophageal reflux disease (GERD). The stomach produces gastric acid and has mechanisms to ensure that this acid does not damage the tissue of the stomach wall. However, there are instances where the acid is able to reach the stomach wall tissue and stomach acid may even extend to other parts of the digestive tract like the esophagus (food pipe). Stomach acid medication may therefore be necessary in these conditions.

Read more on acidic stomach.

What are antacids?

As the name suggests, antacids are any substances that are consumed to neutralize or reduce the acidity of the stomach acid. Essentially antacids are alkalis (bases) that counteract acids. It is used in conditions where the stomach acid is causing inflammation and associated symptoms. Antacids are mainly used in gastroesophageal reflux disease (GERD), gastritis and peptic ulcers. It is also widely used for indigestion and specific symptoms like heartburn which are mainly due to acid reflux.

How do antacids work?

Antacids are alkalis that work by binding to acids. This neutralizes the acids. In other words it raises the pH of the fluid. Depending on the quantity of acids and alkali, an antacid may not completely neutralize all of the stomach acid. Furthermore the stomach is constantly producing gastric acid. Therefore the antacids will at least reduce the strength of the acid.

What are proton pump inhibitors and H2-Blockers?

Proton pump inhibitors (PPIs) are another commonly used drug for reducing stomach acid. It inhibits the stomach from producing acid. H2-blockers are a similar drug in that it reduces stomach acid secretion. Both of these drugs are referred to as acid-suppressing medication. Proton pump inhibitors are generally favored over H2-blockers. These drugs are prescribed for severe or chronic conditions related to gastric acid.

How do acid suppressing drugs work?

Although similar, proton pump inhibitors and H2-blockers work in different ways to reduce somach acid secretion. Proton pump inhibitors block the proton pump (H+/K+ATPase) in the stomach wall which is responsible for stomach acid production. H2-blockers on the other hand block the substance known as histamine which stimulates the stomach to produce gastric acid.  These drugs are mainly used in the treatment for gastritis, peptic ulcers and acid reflux.

What are other stomach acid drugs?

Antacids and proton pump inhibitors are the more widely used drugs for neutralizing and reducing stomach acid. H2-blockers are less frequently used. However, there are several other drugs that may also be utilized for stomach acid related conditions. These other drugs include prostaglandin analogues and sucralfate. Despite working in different ways, both drugs have many serious side effects and are not the first choice of treatment.

How do these other drugs work?

Prostaglandin analogues work by increasing the mucus barrier which protects the stomach lining from the gastric acid. This drug also increases bicarbonate secretion by stomach cells which help neutralize some of the stomach acid.  It acts only for a short period of time unlike with proton pump inhibitors which can act for much longer periods. Prostaglandin analogues should not be used by pregnant women.

Sucralfates form a thick paste when it comes in contact with acids. This paste can then coat the ulcers in the stomach and duodenal wall thereby protecting it. It allows the ulcers time to heal without the repeated irritation caused by stomach acid. However, sucralfates do not act on stomach acid secretion and essentially is not a stomach acid drug. Sucralfates also have a host of side effects if used for prolonged periods of time.

Read more on peptic ulcer disease.

Side Effects

All stomach acid medication have side effects, even antacids if it s used in large amounts for long periods of time. Therefore it is important to consult with a medical professional when symptoms that are relieved by stomach acid medication like antacids are ongoing and not subsiding. Other drugs may be needed to treat and resolve the underlying condition in order for the symptoms to subside and cease.


Antacids are usually considered to have the mildest side effects as compared to other acid drugs. Side effects include nausea, abdominal distension, excessive belching and flatulence. Depending on the type of antacid used, it can also cause diarrhea or constipation. In large doses, antacids can affect the kidneys especially in people with underlying kidney disease.

Acid Suppressing Drugs

Both proton pump inhibitors (PPIs) and H2-blockers have similar common side effects. This includes changes in bowel habit (constipation or diarrhea), nausea, headaches and muscle pains. In addition, proton pump inhibitors may cause abdominal pain, bloating, flatulence and joint pain. H2-blockers can cause fatigue and more serious side effects like bradycardia (slow heart rate), hypotension (low blood pressure) and abnormal liver function.

Prostaglandin Analogues

Prostaglandin analogues have several severe side effects and this is one of the reasons that it is not widely used. The main side effect is that it can induce uterine contractions which can be dangerous in pregnant women and may even result in a miscarriage.


Sucralfates can bind to other drugs and thereby render it ineffective. This is a concern for people who are on chronic medication. In addition, people with kidney disease need to be cautious about long term use of sucralfates.

WARNING: Never use expired drugs or share medication. Always consult with a medical professional prior for an appropriate prescription. Immediately notify a doctor if any side effect arise after starting any of these drugs. Also consider non-drug measures to help reduce the symptoms associated with these stomach acid conditions if a drug is not immediately necessary. However, never stop or reduce the dosage of any prescribed drug unless otherwise advised by a doctor.

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