aluminum hydroxide

Actions and Spectrum: 

The mechanism of action of aluminum hydroxide primarily relates to its role as an antacid. It works by neutralizing excess stomach acid, thereby reducing the acidity of gastric contents. aluminum hydroxide reacts with hydrochloric acid in the stomach to form water and aluminum chloride: 

Al(OH)3 + 3HCl → AlCl3 + 3H2O 

aluminum hydroxide helps alleviate symptoms of heartburn, acid indigestion, and upset stomach by neutralizing gastric acid. 

In addition to its antacid properties, aluminum hydroxide is an adjuvant in vaccines. As an adjuvant, aluminum hydroxide enhances the immune response to vaccines by stimulating the immune system and promoting a more robust and prolonged immune reaction.  

It is essential to note that aluminum hydroxide is not antimicrobial and does not directly target or kill bacteria, viruses, or other pathogens. Its primary role is to neutralize stomach acid and provide symptomatic relief in cases of excessive gastric acidity. 

DRUG INTERACTION

Contraindicated  

Serious Use Alternative  

Monitor Closely  

Minor  

Frequency not defined 

Vomiting 

Aluminum-intoxication 

Chalky taste 

Fecal impaction 

Milk-alkali syndrome 

Nausea 

Rebound hyperacidity 

Hypophosphatemia 

Constipation 

Stomach cramps 

Osteomalacia 

Black box warning: 

None 

Contraindications/caution: 

Contraindications: 

Hypersensitivity 

Caution: 

• aluminum toxicity in renal failure patients:  Prolonged or excessive use of aluminum hydroxide in these patients can lead to aluminum accumulation, potentially causing aluminum toxicity.  
• Hypophosphatemia: aluminum hydroxide can bind to phosphate in the intestines, reducing its absorption and potentially leading to hypophosphatemia (low phosphate levels).  
• Caution in specific medical conditions: Patients with heart failure, cirrhosis, edema, or renal failure may have impaired fluid balance or electrolyte abnormalities.  
• Binding of calcium: aluminum hydroxide can bind to calcium, potentially reducing its absorption. 
• Elderly and constipation: The elderly may be more susceptible to fecal impaction or constipation when using aluminum hydroxide. This is due to the potential drying effect of aluminum hydroxide on the stool. Adequate hydration and dietary fiber intake should be encouraged to mitigate these effects.

Pregnancy consideration: No adverse effects have been reported in animal reproduction studies. It can be used for the treatment of GERD in pregnant women. 

Lactation: Aluminum hydroxide can be excreted in breast milk, monitor infants for adverse effects when administered.  

Pregnancy category: 

• Category A: Satisfactory and well-controlled studies show no risk to the fetus in the first or later trimester. 
• Category B: There is no evidence of risk to the fetus found in animal reproduction studies and there are not enough studies on pregnant women. 
• Category C: Adverse effects on the fetus found with evidence in animal reproduction studies and no adequate evidence for an effect in humans, care must be taken for potential risks in pregnant women 
• Category D: There is adequate data available with sufficient evidence of human fetal risk from various platforms, but despite potential risks may be used only in emergency cases for potential benefits. 
• Category X: Drugs listed in this category outweigh risks over benefits These category drugs should be prohibited for pregnant women. 
• Category N: There is no data available for the drug under this category. 

 

Pharmacology: 

The pharmacology of aluminum hydroxide primarily relates to its actions as an antacid and adjuvant in vaccines.  

• Antacid properties: aluminum hydroxide acts as an antacid by neutralizing excess stomach acid. When taken orally, it reacts with hydrochloric acid in the stomach to form water and aluminum chloride. This neutralization reduces gastric contents’ acidity and relieves heartburn, acid indigestion, and upset stomach symptoms. 
• Acid-buffering capacity: aluminum hydroxide has a high capacity due to its ability to form insoluble aluminum salts. These salts can bind to gastric acid and reduce concentration, helping maintain the stomach’s pH balance. 
• Adjuvant activity: aluminum hydroxide is an adjuvant in some vaccines to enhance the immune response. It is believed that aluminum hydroxide stimulates the immune system by activating specific immune cells, such as macrophages and dendritic cells.  

Pharmacokinetics: 

Absorption 

When taken orally, aluminum hydroxide has limited absorption from the gastrointestinal tract. It primarily remains in the gut and exerts local effects within the stomach. Only a tiny amount of aluminum may be absorbed systemically. 

 

Distribution 

aluminum absorbed from the gastrointestinal tract can distribute to various tissues in the body, including bone, brain, and other organs. However, the extent of systemic distribution is generally limited due to the poor absorption of aluminum hydroxide. 

Metabolism 

aluminum hydroxide is not significantly metabolized in the body. It remains in its original form as aluminum hydroxide until it is excreted. 

Elimination and Excretion 

Most of the aluminum that is absorbed is excreted via the kidneys. Individuals with normal kidney function can efficiently eliminate aluminum. 

Administration: 

Oral administration 

aluminum hydroxide is taken by mouth with water or as directed. 

Tablets or capsules should be swallowed whole without chewing or crushing. 

Patient information leaflet 

Generic Name: aluminum hydroxide 

Why do we use aluminum hydroxide? 

aluminum hydroxide is primarily used for the following purposes: 

• Antacid: aluminum hydroxide is commonly used to relieve heartburn, acid indigestion, and upset stomach symptoms. It neutralizes excess stomach acid, reduces gastric acidity, and relieves discomfort. 
• Gastroesophageal Reflux Disease (GERD): aluminum hydroxide may be used to manage GERD, a chronic condition characterized by stomach acid reflux into the esophagus. By reducing gastric acidity, aluminum hydroxide can help alleviate the symptoms of GERD, such as heartburn and regurgitation. 
• Peptic Ulcer Disease: aluminum hydroxide may treat peptic ulcers, open sores that develop on the stomach lining, or duodenum. It helps to neutralize stomach acid and promote healing of the ulcers, in combination with other medications such as antibiotics and proton pump inhibitors. 
• Hyperphosphatemia: In some cases, aluminum hydroxide is used to manage high levels of phosphate in the blood, known as hyperphosphatemia. It binds to dietary phosphate in the gut, reducing its absorption and helping to control phosphate levels in individuals with kidney disease or other conditions causing phosphate imbalance. 
• Vaccine Adjuvant: aluminum hydroxide is also an adjuvant in certain vaccines. It enhances the immune response to vaccines by stimulating the immune system, leading to a more robust and sustained response to the antigen.