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Aluminium Hydroxide

Last updated on October 25, 2021
Synonyms: Aliuminio hidroksidas; Alumiinihydroksidi; Aluminii Hydroxidum; Aluminium Oxidum Hydricum; Aluminiumhydroxid; Aluminum Hydroxide; Hidróxido de aluminio; Hydroxid hlinitý; Wasserhaltiges Aluminiumoxid
CAS: 21645-51-2 [Al(OH)3]
ATC code: A02AB01
Read code: YM9ik; y00gI [Nutritional Use]; y08EC [Antacid]


Algeldrate (USAN, pINN) is defined as a hydrated aluminium hydroxide with the general formula of Al(OH)3,xH2O

Compounded preparations of aluminium hydroxide may be represented by the following names: Co-magaldrox x/y (BAN) — where x and y are the strengths in milligrams of magnesium hydroxide and aluminium hydroxide respectively.

Pharmacopoeias. In China, Europe, International, Japan, US.

European Pharmacopoeia, 6th ed. (Aluminium Oxide, Hydrated Dried Aluminium Hydroxide BP 2008). It contains the equivalent of 47 to 60% Al2O3. It is a white or almost white, amorphous powder. Practically insoluble in water it dissolves in dilute mineral acids and in solutions of alkali hydroxides. Store in airtight containers at a temperature not exceeding 30°.

European Pharmacopoeia, 6th ed. (Aluminium Hydroxide, Hydrated, for Adsorption Aluminii Hydroxidum Hydricum ad Adsorption em). A white or almost white, translucent, viscous, colloidal gel. A supernatant may be formed upon standing. A clear or almost clear solution is obtained with alkali hydroxide solutions and with mineral acids. pH 5.5 to 8.5. Store at a temperature not exceeding 30°. Do not allow to freeze.

The United States Pharmacopeia 31, 2008(Aluminum Hydroxide Gel). A suspension of amorphous aluminium hydroxide in which there is a partial substitution of carbonate for hydroxide. It is a white viscous suspension from which small amounts of clear liquid may separate on standing. It has a pH of between 5.5 and 8.0. Store in airtight containers. Avoid freezing.

The United States Pharmacopeia 31, 2008 (Dried Aluminum Hydroxide Gel). An amorphous form of aluminium hydroxide in which there is a partial substitution of carbonate for hydroxide. It contains the equivalent of not less than 76.5% of Al(OH)3 and may contain varying quantities of basic aluminium carbonate and bicarbonate. The labelling requirements states that 1 g of dried aluminium hydroxide gel is equivalent to 765 mg of Al(OH)3. It is a white, odourless, tasteless, amorphous powder. Insoluble in water and in alcohol soluble in dilute mineral acids and in solutions of fixed alkali hydroxides. A 4% aqueous dispersion has a pH of not more than 10.0. Store in airtight containers.

Aluminium HydroxideAdverse Effects and Precautions

Aluminium hydroxide, like other aluminium compounds, is astringent and may cause constipation large doses can cause intestinal obstruction. Excessive doses, or even normal doses in patients with low-phosphate diets, may lead to phosphate depletion accompanied by increased bone resorption and hyper-calciuria with the risk of osteomalacia. Aluminium salts are not, in general, well absorbed from the gastrointestinal tract, and systemic effects are therefore rare in patients with normal renal function.

However, care is necessary in patients with chronic renal impairment: osteomalacia or adynamic bone disease, encephalopathy, dementia, and microcytic hypochromic anaemia have been associated with aluminium accumulation in such patients given large doses of aluminium hydroxide as a phosphate-binding agent. Similar adverse effects have also been associated with the aluminium content of dialysis fluids. Aluminium hydroxide used as an adjuvant in adsorbed vaccines has been associated with the formation of granulomas.


For the suggestion that aluminium-containing antacids should not be used in infants, see Toxicity, below.


Aluminium hydroxide is considered by some to be unsafe in patients with porphyria because it has been shown to be porphyrinogenic in animals.

UK licensed product information states that aluminium hydroxide may be unsafe in patients with porphyria undergoing haemodialysis.


References to aluminium toxicity in dialysis patients and the possible association between aluminium ingestion and Alzheimer’s disease are included under Aluminium.

Aluminium accumulation does not generally appear to be significant in patients with normal renal function taking therapeutic doses of aluminium-containing antacids, and there is little evidence that such antacids are a risk factor for Alzheimer’s disease. Elevated plasma-aluminium concentrations have been reported in infants with normal renal function given aluminium-containing antacids but there were no obvious signs of toxicity. There have, however, been reports of phosphate depletion and rickets in a few infants caused by the use of antacids containing magnesium and aluminium hydroxides.

In these cases the antacid had been started within a few months of birth and continued for up to 8 months. In reports that described a total of 3 infants, the authors suggested that the use of soya-based infant feeding formulas, the phytates of which can interfere with mineral absorption, may have exacerbated the phosphate-binding effect of the antacid. In another case a dosing error resulted in the infant receiving an excessive dose of antacid for 6 months. The BNFC advises against the use of any aluminium-containing antacid in neonates and infants.

Aluminium accumulation resulting in osteomalacia or encephalopathy with seizures and dementia has been reported in children with renal failure (but not on dialysis) treated with aluminium-containing phosphate binders. In an adult male patient with severe chronic renal failure who was not on dialysis, self-medication with antacids for at least 3 years resulted in aluminium toxicity associated with encephalopathy, bone disease, and microcytic anaemia. Aluminium-containing antacids should therefore be used with caution in patients with chronic renal failure, especially in children.

Oral citrate salts increase the absorption of aluminium from the gastrointestinal tract and patients with renal failure taking aluminium compounds should avoid citrate-containing preparations, which include many effervescent or dispersible tablets. Ascorbic acid has also been reported to enhance aluminium absorption.


As outlined on site, aluminium compounds used as antacids interact with many other drugs, both by alterations in gastric pH and emptying, and by direct adsorption and formation of complexes that are not absorbed. Interactions can be minimised by giving the aluminium compound and any other medication 2 to 3 hours apart. The absorption of aluminium from the gastrointestinal tract may be enhanced if aluminium compounds are taken with citrates or ascorbic acid (see Toxicity, above).


Aluminium hydroxide, given orally, slowly reacts with the hydrochloric acid in the stomach to form soluble aluminium chloride, some of which is absorbed. The presence of food or other factors that decrease gastric emptying prolongs the availability of aluminium hydroxide to react and may increase the amount of aluminium chloride formed. About 100 to 500 micrograms of the cation is reported to be absorbed from standard daily doses of an aluminium-containing antacid, leading to about a doubling of usual aluminium concentrations in the plasma of patients with normal renal function.

Absorbed aluminium is eliminated in the urine, and patients with renal failure are therefore at particular risk of accumulation (especially in bone and the CNS), and aluminium toxicity (see above).

The aluminium compounds remaining in the gastrointestinal tract, which account for most of a dose, form insoluble, poorly absorbed aluminium salts in the intestines including hydroxides, carbonates, phosphates and fatty acid derivatives, which are excreted in the faeces.

Uses and Administration

Aluminium hydroxide is used as an antacid. It is given orally in doses of up to about 1 g, between meals and at bedtime. In order to reduce the constipating effects, aluminium hydroxide is often given with a magnesium-containing antacid, such as magnesium oxide or magnesium hydroxide.

Aluminium hydroxide binds phosphate in the gastrointestinal tract to form insoluble complexes and reduces phosphate absorption. It may thus be used to treat hyperphosphataemia in patients with chronic renal failure (although aluminium accumulation may be a problem — see Renal Osteodystrophy) or associated secondary hyperparathyroidism. With this use the dose must be adjusted to the individual patient’s requirement but up to about 10 g daily may be given orally in divided doses with meals.

Aluminium hydroxide is also used as an adjuvant in adsorbed vaccines.

Polymyositis and dermatomyositis

Corticosteroids form the basis of the management of polymyositis but the calcinosis that may occur in dermatomyositis does not always respond well. Aluminium hydroxide 1.68 to 2.24 g daily produced clinical improvement with complete clearing of most calcified nodules after 1 year in a patient with calcinosis cutis complicating juvenile dermatomyositis. The calcified masses are made up of hydroxyapatite and amorphous calcium phosphate and reduction in phosphate absorption by aluminium hydroxide probably helped to reverse their formation. Subsequent cases have also reported benefit from aluminium hydroxide treatment in the management of calcinosis.


British Pharmacopoeia 2008: Aluminium Hydroxide Oral Suspension; Aluminium Hydroxide Tablets; Co-magaldrox Oral Suspension; Co-magaldrox Tablets; Compound Magnesium Trisilicate Tablets

The United States Pharmacopeia 31, 2008: Alumina and Magnesia Oral Suspension; Alumina and Magnesia Tablets; Alumina and Magnesium Carbonate Oral Suspension; Alumina and Magnesium Carbonate Tablets; Alumina and Magnesium Trisilicate Oral Suspension; Alumina and Magnesium Trisilicate Tablets; Alumina, Magnesia, and Calcium Carbonate Oral Suspension; Alumina, Magnesia, and Calcium Carbonate Tablets; Alumina, Magnesia, and Simethicone Oral Suspension; Alumina, Magnesia, and Simethicone Tablets; Alumina, Magnesia, Calcium Carbonate, and Simethicone Tablets; Alumina, Magnesium Carbonate, and Magnesium Oxide Tablets; Aluminum Hydroxide Gel; Aspirin, Alumina, and Magnesia Tablets; Aspirin, Alumina, and Magnesium Oxide Tablets; Dried Aluminum Hydroxide Gel Capsules; Dried Aluminum Hydroxide Gel Tablets; Dried Aluminum Hydroxide Gel

Proprietary Preparations

Argentina: Pepsamar

Australia:: Alu-Tab

Austria: Anti-Phosphat

Brazil: Aludroxil Aziram Biodrox Ductogel Fluagel Gastromax Gastrox Gelpan Hidroxialiv Kaogel Mylanta Plus Natusgel Noacid Pepsamar Peptgel

Canada: Alu-Tab Alugel Amphojel Basaljel

Chile: Risthal

Germany: Aludrox Anti-Phosphat

Greece: Alu-Cap Pepsamar

Hong Kong: Alu-Tab

India: Aludrox Tricaine-MPS

Ireland: Aludrox

Israel: Alu-Cap

Italy: Poiisiion

Malaysia: Alu-Tab

Mexico: Domigei Magnaium

New Zealand: Alu-Tab Amphojel

Philippines: Alu-Tab

Poland: Alusal

Portugal: Geluminaf Pepsamar

South Africa: Alukon Amphojel

Singapore: Alu-Tab

Spain: Alugel Pepsamar

Switzerland: Antiphosphate Gastracol

UK: Alu-Cap Aludrox

USA: ALternaGEL Alu-Cap Alu-Tab Amphojel Dialume Nephrox

Venezuela: Gelidral

Used as an adjunct in

Argentina: Dristan Analgesico Dristan Compuesto Truxa R

Brazil: Analtrix Butazolon Posdrink Redentil Resprax

Canada: C2 with Codeine

Chile: Silartrin

France: Finidol

Greece: Ascriptin

Indonesia: Nas-pro

Israel: Ascriptin

Italy: Ascriptin Via Mai

Mexico: Ascriptin Meprosona

Switzerland: Alcacyl Contre-Douleurs plus Contre-Douleurs

USA: Arthritis Pain Formula Ascriptin Asprimox Cama Arthritis Pain Reliever Cope Magnaprin Vanquish

Venezuela: Ascriptin

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