How heartburn medication works
Gastric acidity reduction: The goal of GORD medication
The goal of the most common GORD medications available is to make the contents of the stomach less acidic than normal. While drugs with other mechanisms of action (such as those that augment the function of the LOS) have been tried, they have been largely unsuccessful and are rarely used. To understand how acid reducing drugs work, you must understand the balancing act that occurs in the stomach throughout the day.
The role of gastric acid in digestion
What is pH?
First, pH is a measure of acidity. The lower the pH of a material, the stronger the acid is. Water, which is neutral, has a pH of 7. Anything below 7 is acidic. Anything above 7 is alkaline. The change of 1 unit is equal to 10 times more alkalinity or acidity. For example, going from a pH of 5 to a pH of 4 is 10 times more acidic, and a change from a pH of 8 to 10 is 100 times more alkaline.
So what does this mean in the stomach?
Special cells in the stomach, called parietal cells, secrete extremely strong hydrochloric acid. Normally, they secrete enough acid to keep the gastric contents in the “between-meals” stomach at a pH of 1 to 2; very acidic. In between meals when the stomach is empty, the volume of this strongly acid gastric juice is very small and so it the tendency to reflux. The exception is when a person lays down during sleep – then reflux can occur even with small gastric volumes if the LOS is severely damaged.
What happens when we eat?
When we eat, acid secretion increases to aid digestion. In fact, acid secretion increases when we even think about eating and is further stimulated by the entry of food into the mouth. Since the food we eat is generally neutral or alkaline, acid secretion amps up to reduce the pH in the stomach. As the stomach empties after a meal, acid secretion decreases and returns to its resting state. A hormone called gastrin (produced in the stomach) controls this activity.
An interesting recent discovery is that the pH of the gastric contents is not equally distributed during a meal. As the stomach fills, the acid tends to rise to the top of the column of food. As a result, there is an “acid pocket” right at the top of the full stomach, near where the Oesophagus enters.
When reflux occurs, the acid can damage the Oesophagus
When reflux occurs, the acidic gastric contents, either acidic liquid or acidic liquid mixed with undigested food, enter the Oesophagus. Because of the acid pocket, the reflux tends to be acidic even in the full stomach where the food has neutralized some of the acid. This acid can damage the lining of the Oesophagus and stimulate nerve endings in the lining, resulting in acidity symptoms such as heartburn, and potentially causing erosions or acid burns.
Damage to the lining of the Oesophagus is dependent on:
- The amount of acid entering the Oesophagus, exacerbated by the presence of the acid pocket,
- How quickly the refluxed material is cleared from the Oesophagus back into the stomach, and
- The strength of the acid (i.e. pH).
- The presence of bile and pepsin in the reflux content.
- The “pooling” of reflux content at night during sleep.
Heartburn medication: Decreasing gastric acidity symptoms with acid neutralizers
The objective of acid suppressive heartburn medication is to decrease gastric acidity and the related acidity symptoms. It has been shown that when the pH of the gastric contents is increased above 4:
- There is minimal damage to the normal lining of the Oesophagus
- Heartburn does not occur,
- Erosions do not occur, and
- If damage is present, it is not aggravated by the ongoing reflux, allowing any damage that has resulted from previous reflux to heal.
These drugs control acidity symptoms and decrease the probability of damage when reflux occurs. They do not address the cause of reflux, which is the damaged lower Oesophageal barrier (sphincter), and they do not prevent reflux, which continues at its prior level while the heartburn medication is being taken. All they do is raise the pH of the material that enters the Oesophagus high enough that reflux does not cause heartburn or erosions in the lining of the Oesophagus. These drugs do not prevent some complications of GORD such as Barrett’s Oesophagus and cancer.
Acid neutralizers that are taken before, during, or after a meal are very effective in controlling heartburn. These drugs produce a very transient decrease in gastric acid, usually lasting minutes. However, they act at a crucial time when the stomach is filling and very likely neutralize the acid pocket that sits on top of the column of food. This short term action works well for immediate heartburn control.
Your goal: The least frequent dose of the least powerful heartburn medication
As with any drug used to control symptoms, you should aim to use the least frequent dose of the least powerful drug needed to relieve your symptoms. The most powerful medications have several health risks if used daily over a long period of time, which is not true for H2 blockers and antacids. Ideally, this will be combined with an acid reflux diet, avoiding trigger foods, and smaller meal portions to reduce GORD symptoms. This strategy will provide the best bang for your buck and the least likelihood of complications from the drugs. And understand that any heartburn medication will not cure your GORD. GORD is a chronic disease and, if you are using these drugs now, you will likely need them throughout your life. Furthermore, if your GORD continues to progress with increasing sphincter damage, you will likely need to increase the amount and strength of the drugs needed to control your symptoms.
This article is from Reflux MD – How heartburn medication works – RefluxMD