For individuals needing to reduce stomach acid and support the treatment of abdominal pain, acid reflux, and indigestion, Aluminum hydroxide is one of the commonly chosen medications. This article will provide an overview of what Aluminum hydroxide is, its uses, and how to use it safely.
1. What Is Aluminum Hydroxide?
Aluminum hydroxide is an antacid belonging to the gastrointestinal drug group, available in various forms, including capsules (475mg), soft gel capsules (300mg, 500mg, 600mg), film-coated tablets (600mg), and suspensions (320 mg/5 ml, 450 mg/5 ml, 600 mg/5 ml, 675 mg/5 ml).
When taken orally, aluminum chloride is formed as a result of the slow reaction between aluminum hydroxide and hydrochloric acid in the stomach. A small amount is absorbed into the body. If food remains in the stomach, the medication takes longer to leave, prolonging its reaction with gastric acid and leading to higher aluminum chloride levels.
In the small intestine, the digestive process rapidly converts aluminum chloride into insoluble alkaline aluminum salts, which are poorly absorbed. These aluminum salts may include a mixture of aluminum hydroxide, basic aluminum carbonate, oxyaluminum hydroxide, and aluminum soaps.
Phosphate from food also binds with aluminum hydroxide in the small intestine, forming insoluble aluminum phosphate, which cannot be absorbed in the digestive tract and is excreted in the feces.
Aluminum hydroxide is not metabolized in the body. In individuals with normal kidney function, only about 17-30% of the aluminum chloride formed is absorbed and rapidly excreted through the kidneys. However, in patients with renal impairment, aluminum accumulation is more likely, particularly in the central nervous system and bones, which can lead to aluminum toxicity.
The absorbed aluminum binds to serum proteins such as albumin and transferrin, making it difficult to remove through dialysis. Most of the remaining aluminum in the digestive tract forms poorly absorbed aluminum salts, which are then excreted in the feces.
Dried aluminum hydroxide gel is an amorphous powder that is insoluble in water and alcohol. This powder contains 50–57% aluminum oxide in the form of hydrated oxide and may also contain varying amounts of aluminum carbonate and bicarbonate.
Aluminum hydroxide is an inorganic salt used as an active ingredient in antacid medications. It neutralizes excess hydrochloric acid in the stomach, helping to reduce acidity. This action helps relieve symptoms associated with peptic ulcers, heartburn, acid reflux, bloating, and gastroesophageal reflux disease (GERD).
Since aluminum hydroxide tends to cause constipation, it is often combined with antacids containing magnesium (magnesium hydroxide or magnesium oxide), which have a laxative effect, to help balance this side effect.
Dietary phosphate in the stomach and intestines binds with aluminum hydroxide, forming insoluble complexes that reduce phosphate absorption. Due to this mechanism, aluminum hydroxide is also used to treat hyperphosphatemia in patients with secondary hyperparathyroidism or kidney failure.
2. Indications and Contraindications for Aluminum Hydroxide
Indications for Aluminum Hydroxide, Aluminum hydroxide is prescribed for the following conditions:
- Relief of symptoms caused by excess stomach acid, such as heartburn, acid reflux, bloating, and indigestion due to increased gastric acid.
- Patients with hyperacidity caused by peptic ulcers (gastric and duodenal ulcers).
- Prevention and treatment of gastric and duodenal ulcers or gastrointestinal bleeding due to excessive stress.
- Treatment of gastroesophageal reflux disease (GERD) and its associated symptoms.
- Management of hyperphosphatemia, when combined with a low-phosphate diet.
Do not use Aluminum Hydroxide in the following cases:
- Hypersensitivity to aluminum hydroxide.
- Patients with hypophosphatemia (low phosphate levels).
- Young children, due to the risk of aluminum toxicity, especially in those with dehydration or kidney failure.
3. Side Effects of Aluminum Hydroxide
Common side effects or health issues that may occur when using Aluminum hydroxide include:
- Nausea
- Vomiting
- Rebound acid hypersecretion
- Aluminum toxicity
- Low blood phosphate levels (hypophosphatemia)
- Constipation (which may lead to hemorrhoids or bowel obstruction)
- Abnormal stool consistency
- Stomach cramps
- Milk-alkali syndrome
- Bone softening (osteomalacia)
Serious side effects of Aluminum hydroxide may include:
- Mental or mood changes, such as confusion or difficulty sleeping.
- Painful urination.
- Severe stomach or abdominal pain.
- Vomiting that resembles coffee grounds (a sign of gastrointestinal bleeding).
4. Drug Interactions
Aluminum hydroxide may alter the absorption of certain medications when taken together, including iron salts, isoniazid, digoxin, indomethacin, allopurinol, corticosteroids, penicillamine, benzodiazepines, ranitidine, ketoconazole, phenothiazines, and itraconazole. Therefore, it should be taken at a different time from antacids to avoid interactions.
Do not take Aluminum Hydroxide with tetracyclines, as dried aluminum hydroxide gel reduces tetracycline absorption by forming insoluble complexes.
5. How to Use Aluminum Hydroxide
5.1. Usage for Adults
For excess gastric acid:
- The dosage required to neutralize stomach acid varies depending on the individual, the amount of gastric acid secretion, and the buffering capacity of the specific formulation.
- In vivo, the acid-neutralizing capacity of antacids can vary significantly, even among formulations of the same volume. When taken on an empty stomach, Aluminum Hydroxide starts working within 20 to 60 minutes. However, if taken about 1 hour after a meal, its acid-neutralizing effect can last up to 3 hours.
- Liquid antacids (suspensions) dissolve more easily and are significantly more effective at neutralizing gastric acid compared to powder and tablet forms. For this reason, antacid suspensions are generally preferred over other forms. However, not everyone can tolerate the suspension form, especially individuals who are sensitive to texture or taste, as it may cause throat discomfort. For tablet forms, it is essential to chew thoroughly before swallowing to maximize effectiveness.
- The maximum recommended dosage for treating digestive disorders and indigestion should not be used for more than 2 weeks, unless advised or supervised by a doctor or healthcare professional.
Treatment of Gastric and Duodenal Ulcers
- Typical dosage: 15 - 45 ml per dose, taken every 3 to 6 hours or 1 to 3 hours after meals and before bedtime.
- For patients with uncomplicated duodenal ulcers: To maximize antacid effects, the medication should be taken 1 to 3 hours after meals and at bedtime to prolong acid neutralization.
- An additional dose may be taken between scheduled doses to relieve pain.
- Typically prescribed for 4 - 6 weeks. For gastric ulcers, antacids are usually continued until complete ulcer healing.
Gastroesophageal Reflux Disease (GERD) Treatment
- Take Aluminum Hydroxide every 1 hour. If symptoms persist, the dosing may be increased to every 30 minutes.
- For long-term treatment, take the medication 1 and 3 hours after meals and before bedtime to maintain acid neutralization.
Prevention of Gastrointestinal Bleeding and Stress Ulcers
- Dosage: 30 - 60 ml per dose, taken every 1 hour.
- For gastric bleeding: Antacid dosage should be adjusted to maintain a gastric aspirate pH > 3.5.
- For severe cases, the antacid suspension should be diluted in water or milk and continuously infused into the stomach.
- Dosage adjustments are necessary to maintain a gastric pH > 5.
Treatment of Hyperphosphatemia
- Along with a low-phosphate diet, take 30 - 40 ml of aluminum hydroxide suspension, 3 to 4 times per day.
- Take 500 - 1800 mg, 3 to 6 times per day, between meals and at bedtime. For optimal phosphate binding, it is best to take the medication with meals or within 20 minutes after eating.
To Reduce the Risk of Acid Aspiration During Anesthesia
- Administer an antacid suspension 30 minutes before anesthesia to reduce the risk of acid aspiration.
5.2. Dosage for Children
Treatment of Gastric Ulcers
- Children: 5 - 15 ml of aluminum hydroxide suspension, taken every 3 - 6 hours or 1 to 3 hours after meals and at bedtime.
Prevention of Gastrointestinal Bleeding in Children
- Infants and young children: 2 - 5 ml per dose, taken every 1 - 2 hours.
- Older children: 5 - 15 ml per dose, taken every 1 - 2 hours.
- Dosage adjustments may be necessary to maintain gastric pH > 5 for effective prevention.
Treatment of Hyperphosphatemia in Children
- Along with a low-phosphate diet, administer 30 - 40 ml of aluminum hydroxide suspension, 3 to 4 times per day.
- The dosage is 50 - 150 mg/kg per 24 hours, divided into smaller doses and taken every 4 - 6 hours. Adjust the dose as needed to maintain normal serum phosphate levels.
5.3. Precautions When Using Aluminum Hydroxide
- Use with caution in patients with congestive heart failure, kidney disease, edema, cirrhosis, those on a low-sodium diet, and individuals who have recently experienced gastrointestinal bleeding.
- Elderly individuals, due to illness or medication use, may experience constipation and hard stools. Caution should be taken regarding potential drug interactions.
- For patients undergoing dialysis or long-term use of aluminum-containing antacids, serum phosphate levels should be monitored regularly, either monthly or every two months.
The above information provides an overview of Aluminum Hydroxide, helping you use the medication effectively and safely for your health. Always follow your doctor's instructions for optimal results.
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