Melox Plus: Mechanism of Action, Administration, Side Effects, Interactions and Contraindications

Antacids are a class of medications used to treat conditions caused by acid produced by the stomach.

The stomach naturally secretes an acid called hydrochloric acid that helps break down protein.

This acid makes the stomach contents acidic in nature, with a pH level of 2 or 3 when acid secretion is active (pH levels are a measure of the acidity in the stomach – the lower the number , the higher the acidity).

The stomach, duodenum, and esophagus are protected from acid by various protective mechanisms.

When there is too much acid or the protective mechanisms are inadequate, the lining of the stomach, duodenum or esophagus can be damaged by the acid, leading to inflammation and ulcerations and its various gastrointestinal symptoms, such as:

  • Nausea, abdominal pain, and heartburn (due to gastroesophageal reflux disease or GERD).

Melox plus reduces acidity by neutralizing (counteracting) acid, reducing acidity in the stomach, and reducing the amount of acid that refluxes into the esophagus or empties into the duodenum.

Melox plus also works by inhibiting the activity of pepsin, a digestive enzyme produced in the stomach that is only active in an acidic environment and, like acid, is believed to be harmful to the lining of the stomach, duodenum, and esophagus. .

It is also used to relieve additional gas symptoms such as belching, bloating, and a feeling of pressure / discomfort in the stomach / gut. Simethicone helps break up gas bubbles in the intestine.

Liquid antacids generally work faster / better than tablets or capsules. This medicine works only with the acid in the stomach.

It can be used alone or with other medications that reduce acid production (for example, H2 blockers such as cimetidine / ranitidine and proton pump inhibitors such as omeprazole).

If you are treating yourself with this medicine, please read the package directions carefully before you start using this product to make sure it is right for you.

What is Aluminum Hydroxide, Magnesium Hydroxide, and Simethicone?

Aluminum and magnesium are natural minerals. Aluminum hydroxide and magnesium hydroxide are antacids.

Simethicone allows gas bubbles in the stomach and intestines to gather together more easily, making it easier for gas to pass.

Aluminum hydroxide, magnesium hydroxide, and simethicone are combination medications used to treat heartburn, acid indigestion, upset stomach, and bloating caused by gas.

Aluminum hydroxide, magnesium hydroxide, and simethicone may also be used for purposes not listed in this medication guide.

Mechanism of action of melox plus

When excessive amounts of acid are produced in the stomach, the natural mucosal barrier that protects the stomach lining can damage the esophagus in people with acid reflux.

Melox plus contains alkaline ions that chemically neutralize gastric acid in the stomach, reducing damage and relieving pain.

After oral administration, the aluminum hydroxide in melox plus slowly solubilizes in the stomach and reacts with hydrochloric acid to produce aluminum chloride and water.

This chemical reaction neutralizes gastric acid secretions and increases gastric pH.

Melox plus is available without a prescription and is taken by mouth to quickly relieve occasional heartburn, the main symptom of gastroesophageal reflux disease, and also indigestion.

Treatment with melox plus is only symptomatic and only justified for minor symptoms.

Melox plus is different from acid-reducing drugs, such as H2 receptor antagonists or proton pump inhibitors, and it does not kill the Helicobacter pylori bacteria, which cause most ulcers.

Non-particulate antacids (sodium citrate, magnesium trisilicate) increase gastric pH with no effect on gastric volume (possibly increase gastric volume slightly).

Increasing gastric pH inhibits the proteolytic action of pepsin, an effect that is particularly important in patients with peptic ulcer disease. Increasing the pH and decreasing the production of pepsin help heal peptic ulcers.

While gastric acids are neutralized, actual acid secretion is not effected. Aluminum chloride salt produced in the stomach reacts with bicarbonate in the small intestine to minimize the risk of systemic alkalosis.

Compared to magnesium hydroxide, aluminum hydroxide reacts slowly with bicarbonate because it dissolves slowly in the stomach, adding to its longer duration of action.

In the treatment of esophageal reflux, the increase in gastric pH produced by antacids, including aluminum hydroxide, causes an increase in the pressure of the lower esophageal sphincter. This increased pressure minimizes the amount of reflux into the esophagus.

Aluminum hydroxide complexes with dietary phosphate to form insoluble aluminum phosphate, which is excreted in the feces. This reduces the amount of phosphate that is available for absorption.

For aluminum hydroxide to be beneficial in preventing phosphate absorption, it must be administered with meals or snacks.

This hypophosphatemic effect of aluminum hydroxide has been used in the treatment of hyperphosphatemia associated with chronic renal failure, hyperparathyroidism secondary to chronic hemodialysis, and universal calcinosis.

However, calcium carbonate is the preferred treatment for these conditions. The decrease in phosphate absorption causes an increase in calcium absorption.


Melox plus is administered orally. The aluminum hydroxide in melox plus slowly solubilizes in the stomach and reacts with hydrochloric acid in the stomach to produce aluminum chloride and water.

About 17-30% of aluminum chloride is rapidly absorbed and excreted by the kidneys in patients with normal kidney function. In the small intestine, aluminum chloride is rapidly converted to insoluble and poorly absorbed basic aluminum salts.

Aluminum also combines with dietary phosphate in the intestine to form insoluble, nonabsorbable aluminum phosphate that is excreted in the feces. Aluminum that is not absorbed remains in the gastrointestinal tract and is excreted in the feces.

How to use the melox plus

If you are taking the chewable tablets, chew well before swallowing, then drink a full glass of water (8 ounces or 240 milliliters).

Adults and children 12 years and older : Take 2 to 4 teaspoons (10-20 ml) or 2 to 4 tablets by mouth every 4 to 6 hours one before or 3 hours after a meal. Do not take more than 12 tablets a day.

Children under 12 years : consult a doctor.

Measure the dose carefully using a tablespoon / cup medicine. Do not use a household spoon because you may not receive the correct dose.

It is important to note that when melox plus is taken on an empty stomach, they provide a 20-40 minute acid reduction just because melox plus empties quickly into the duodenum.

When taken after a meal, (about 1 hour later) melox plus reduces acid for at least three hours, as the meal from the meal decreases the emptying of the antacid (and the meal) from the stomach.

If your acid problems persist or worsen after using this product for 1 week, or if you think you have a serious medical problem, seek medical attention immediately.

Ask your doctor if this is the right medicine for you.

What to drink, tablet or liquid?

If you have heartburn, which formula of melox plus arrives faster: liquid or tablet? The Center for Human Drug Research in the Netherlands, studied the patients to see if there were any differences, and reported their findings.

Each patient took both pills and liquid. In half of the cases, the liquid was active and the pills were placebos, and in the other half, the pills were real and the liquid was placebo. In that way, the subjects could not guess which substance was active.

Patients who took the active liquid said they felt better after 19 minutes, while the active pills took more than an hour to make anyone feel better. However, after three hours, there were no differences between the two groups.

When to use melox plus

Melox plus is a good treatment for heartburn that occurs from time to time. Take melox plus about 1 hour after eating or when you have heartburn. If you take them for symptoms at night, DO NOT take them with food.

Melox plus cannot treat more serious problems, such as appendicitis, a stomach ulcer, gallstones, or intestinal problems. Talk to your provider if you have:

Pain or symptoms that do not improve with melox plus:

  • Symptoms every day or at night.
  • Nausea and vomiting
  • Bleeding in the bowel movements or intestinal darkening.
  • Swelling or cramps
  • Pain in the lower belly, side, or back.
  • Diarrhea that is severe or does not go away.
  • Fever with stomach pain.
  • Chest pain or shortness of breath
  • Difficulty swallowing
  • Weight loss you can’t explain.

What happens in case of overdose of melox plus?

Avoid taking other medications within 2 hours before or after taking melox plus. Stop using melox plus and call your doctor at once if you have:

Bone pain, muscle weakness; confusion, changes in your mental status, seizures; or pale skin, feeling dizzy or short of breath, fast heart rate.

Less serious side effects are more likely, and you may not have any.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice on side effects.

Melox plus side effects

Melox plus has few side effects when taken as directed on the label. Side effects are more common when the product is used excessively or taken for longer than intended.

The side effects of melox plus are directly related to the ingredients they contain. Diarrhea is more common with this product than constipation.

Some combination products have side effects that cancel each other out (for example, aluminum causes constipation and magnesium causes diarrhea, so melox plus is more likely to have a neutral effect on the gut).

If these symptoms persist or become severe, notify your doctor. If you take large amounts of melox plus, you may be at risk of losing calcium, which can lead to weak bones ( osteoporosis ).

Tell your doctor right away if you have any of the following symptoms of low phosphate: loss of appetite, unusual tiredness, muscle weakness.

If you notice other effects not listed above, contact your doctor or pharmacist.

Aluminum : constipation, low blood phosphate levels, aluminum toxicity, osteomalacia.

Magnesium : diarrhea, nausea, vomiting, high levels of magnesium in the blood.

Melox plus, taken at too high a dose for too long a period, can also cause a condition called acid rebound. This is when the stomach produces even more acid after consuming food and drink.

Melox plus interactions with other medications

Melox plus can change the way your body absorbs the other medicines you are taking. It is better to take any other medicine 1 hour before or 4 hours after taking melox plus.

Talk to your provider or pharmacist before taking melox plus regularly if:

  • You have kidney disease, high blood pressure, or heart disease.
  • You are on a low sodium diet.
  • You are already taking calcium.
  • You are taking other medicines every day.
  • You have had kidney stones.

This product may react with other medications (such as digoxin, iron, pazopanib, antibiotics, quinolone antibiotics such as ciprofloxacin), preventing them from being fully absorbed by the body.

When melox plus is taken with acidic medicines (eg Digitek, phenytoin [Dilantin], chlorpromazine [Thorazine], [isoniazid]), they cause decreased absorption of acidic medicines, causing low blood concentrations of the medications, which ultimately results in reduced effects of the medications.

Melox plus taken with drugs such as pseudoephedrine (Sudafed, Semprex D, Clarinex-D 12 h, Clarinex-D 24 h, Deconsal, Entex PSE, Claritin D and more) and levodopa (Dopar), increase the absorption of drugs and cause toxicity / adverse events due to increased blood levels of drugs.

When melox plus is taken with other medications (such as tetracycline) it will bind to the medications and reduce their absorption and effects.

Sodium bicarbonate has a strong effect on the acidity of the urine, and this can affect the elimination (excretion) of some medications by the kidney.

Thus, sodium bicarbonate inhibits the excretion of basic drugs such as quinidine (Quinidex, quinidine glucinate, quinidine sulfate, quinidine injection) and amphetamines, and increases the excretion of acidic drugs such as aspirin.

It is important to discuss the use of melox plus with a doctor or pharmacist, especially if it is used in combination with other prescription medications to avoid drug interactions.

Is the melox plus safe?

When taken at the recommended dose, for a short time, by people without contraindications, melox plus is considered safe.

However, melox plus only relieves symptoms and does not cure the underlying problem causing the symptoms. This means that they can mask some serious conditions, such as gastric cancer.

If you are taking melox plus more than two or three times a week for more than two weeks, you should speak to your doctor.

Even if your condition is diagnosed as gastroesophageal reflux, other medications (such as H2 antagonists, proton pump inhibitors), which work by reducing or preventing stomach acid secretion rather than neutralizing it, may be more appropriate.

Always talk to your doctor if you have reflux-like symptoms that do not go away with melox plus. Some symptoms of heart disease (such as angina or a heart attack) are similar to those of reflux or heart burn.

Melox plus should not be given to children under six years of age. It may not be safe in people with certain medical conditions, such as gastrointestinal bleeding, liver or kidney disease, or heart disease.

Pregnant or lactating women should also talk to their pharmacist or doctor before using melox plus.

Contraindications / precautions


Melox plus is relatively contraindicated in patients with hypophosphatemia. Melox plus binds with phosphate from the diet in the intestine, making it difficult to absorb.

In rare cases, patients with normal blood phosphate may develop hypophosphatemia if phosphate intake is not adequate.


Melox plus should be used with caution in patients with chronic diarrhea. Although the constipation effects of melox plus can correct diarrhea, diarrhea increases the risk of developing hypophosphatemia associated with the use of melox plus.

Anticholinergic medications, constipation, dehydration, fecal impaction, gastrointestinal bleeding, gastrointestinal obstruction, hemorrhoids, ileus.

Melox plus causes constipation and should be used with extreme caution in patients predisposed to constipation or complications associated with constipation, including patients receiving antidiarrheal or anticholinergic medications and patients with gastric outlet obstruction.

Patients with constipation, fecal impaction, gastrointestinal obstruction, ileus, hemorrhoids, or undiagnosed gastrointestinal or rectal bleeding should receive melox plus with caution.

These conditions may become severe or the patient may develop sepsis, peritonitis, or ischemic bowel.

Patients who are dehydrated, have fluid restriction, or have a pre-existing decreased intestinal motility are predisposed to developing gastrointestinal obstruction with the use of melox plus.

Neonates, kidney disease, kidney failure, kidney failure

Melox plus should be used with caution in neonates and in patients with renal impairment or kidney disease due to the increased risk of developing aluminum toxicity.

Dialysis-associated dementia or encephalopathy can occur in dialysis patients with long-term use of aluminum-containing medications.

Do not use in patients with renal impairment unless they are being closely monitored for signs and symptoms of toxicity.

Ascites, heart failure, liver disease

Use melox plus with caution in patients on sodium-restricted diets and in those with congestive heart failure, kidney failure, edema, kidney disease, or cirrhosis with ascites (severe liver disease) as the total daily dose may exceed 5 mEq (115 mg ) of sodium.


Use melox plus with caution in geriatric patients. Elderly patients are predisposed to constipation and generally have declining kidney function, putting them at increased risk for problems associated with aluminum-induced constipation and aluminum toxicity.

Colostomía, diverticulitis, ileostomía

Melox plus is relatively contraindicated in patients with a colostomy, diverticulitis, or ileostomy because the drug increases the risk of developing an electrolyte imbalance.

The pregnancy

Melox plus has not been assigned a specific pregnancy risk category by the Food and Drug Administration.

When chronic use and high doses are avoided, melox plus appears to be safe and effective for the occasional relief of dyspepsia and heartburn in the mother during pregnancy.

When used occasionally at recommended doses, melox plus has not been found to produce teratogenic effects and is generally considered safe during pregnancy, provided the pregnant woman has no concerns with kidney dysfunction.

Increased tendon reflexes have been reported in newborns whose mothers were using high-dose, chronic aluminum-containing antacid products during pregnancy.

When chronic use and high doses are avoided, melox plus appears to be safe and effective for the occasional relief of dyspepsia and heartburn in the mother during lactation.

Melox plus does not significantly enter breast milk and no problems have been reported during lactation.

It may be recommended for the relief of dyspepsia or heartburn during lactation, as the combined antacids allow comparative relief of symptoms at lower doses.

Children, infants

Over-the-counter use of melox plus is not recommended as an antacid in infants and children <2 years without the supervision of a physician due to the serious nature of complications associated with reflux in infants such as:

Growth failure, esophageal stricture, Barrett’s esophagus, intraesophageal polyps, and associated lung diseases.

Melox plus has been used in children for esophagitis and peptic ulcer disease, although the safety has not been clearly established.