Alamag (Aluminum Hydroxide and Magnesium Hydroxide Chewable Tablets)

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.

If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

• If your symptoms or health problems do not get better or if they become worse, call your doctor.
• Do not share your drugs with others and do not take anyone else's drugs.
• Keep a list of all your drugs (prescription, natural products, vitamins, OTC) with you. Give this list to your doctor.
• Talk with the doctor before starting any new drug, including prescription or OTC, natural products, or vitamins.
• Some drugs may have another patient information leaflet. Check with your pharmacist. If you have any questions about this medicine, please talk with your doctor, nurse, pharmacist, or other health care provider.
• If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

This information should not be used to decide whether or not to take Alamag or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to Alamag (aluminum hydroxide and magnesium hydroxide chewable tablets). This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using this medicine.

Review Date: October 4, 2017

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

• Hard stools (constipation).
• Loose stools (diarrhea).

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-FDA-1088. You may also report side effects at http://www.fda.gov/medwatch.

Applies to aluminum hydroxide / magnesium hydroxide: oral suspension, oral tablet, oral tablet chewable

Gastrointestinal

Gastrointestinal side effects have been reported the most frequently. These have included constipation (secondary to aluminum hydroxide therapy) and diarrhea (secondary to magnesium hydroxide therapy). These agents are combined so lower doses may be used and the constipating and diarrheal effects may be balanced out. However, diarrhea appears to be the dominating effect, regardless of the ratio. Rarely, gastrointestinal obstruction has occurred with the use of aluminum hydroxide.[Ref]

General

Sources of aluminum in patients with renal failure have included water used for dialysate solutions, in addition to aluminum hydroxide. Adverse effects of aluminum accumulation in these patients has led to monitoring of water source aluminum content by dialysis units and periodic measurements of serum aluminum in patients undergoing chronic dialysis.

High aluminum concentrations in patients are generally also associated with high daily dosage. One study suggested that increased aluminum concentrations in uremic patients was most significant with daily doses greater than 3 grams of aluminum hydroxide. Age of the patient has also been directly correlated with aluminum concentrations, with younger age groups perhaps demonstrating higher concentrations.

Concurrent administration of aluminum hydroxide with citrate containing products has been associated with unusually high serum concentrations of aluminum and, especially in cases of renal failure, severe toxicity. It was speculated that citrate increases aluminum's solubility and absorption.

Aluminum concentrations during aluminum hydroxide therapy have also been correlated with body iron stores. One study demonstrated a negative correlation between serum aluminum concentrations and serum ferritin levels. It was postulated that high serum ferritin and high transferritin saturation might hamper gut absorption of aluminum.

During long-term use, aluminum has been shown to deposit in bone, joints, and the brain of patients who accumulate aluminum.

Signs and symptoms of hypermagnesemia may include hypotension, nausea, vomiting, EKG changes, respiratory depression, altered mental status, and coma.[Ref]

Although the majority of aluminum ingested is eliminated by the gastrointestinal tract, absorption of aluminum and increases in serum concentrations have been demonstrated. Accumulation of aluminum and resulting toxicity is confined to patients with renal dysfunction and impaired elimination of aluminum.

Magnesium may be systemically absorbed following administration of magnesium hydroxide. In patients with normal renal function, increased magnesium elimination in the urine occurs and no significant changes in serum magnesium levels would be expected. However, magnesium may accumulate in patients with renal insufficiency.[Ref]

Metabolic

Metabolic side effects have included hypophosphatemia with the use of aluminum hydroxide. In patients on long-term aluminum hydroxide therapy, especially in association with poor diets, hypophosphatemia may result in muscle weakness, rhabdomyolysis, hemolysis, and encephalopathy.[Ref]

Aluminum hydroxide complexes with phosphate in the gut to form insoluble aluminum phosphate, thus inhibiting the absorption of dietary phosphate. Aluminum hydroxide is commonly used in patients with renal dysfunction to regulate the accumulation of phosphate due to decreased elimination.

Hypophosphatemia is thought to stimulate the conversion of calcifediol (25-hydroxy vitamin D3) to calcitriol (1,25-dihydroxy vitamin D3), a potent stimulator of calcium and phosphorus intestinal absorption and osteoclastic resorption. Hypercalciuria is generally associated with hypophosphatemia.[Ref]

Musculoskeletal

Aluminum hydroxide associated hypophosphatemia, if severe and chronic, results in decreased bone mineralization and potentially osteomalacia. Hypophosphatemia is also thought to stimulate the conversion of calcifediol (25-hydroxy vitamin D3) to calcitriol (1,25-dihydroxy vitamin D3), a potent stimulator of osteoclastic resorption, contributing to osteomalacia. These patients generally require phosphorus replacement therapy. Symptoms of osteomalacia may take several weeks to resolve.

Osteomalacia due to aluminum deposition in bone is generally only seen in patients with chronic renal failure. Bone formation slows in response to aluminum bone deposits. Aluminum may also deposit in joint tissue, resulting in arthropathy and hydrarthrosis.[Ref]

Musculoskeletal side effects have included osteomalacia, due to aluminum hydroxide, which may occur by two different mechanisms. Osteomalacia may occur due to hypophosphatemia or due to aluminum accumulation in bone. Osteomalacia due to hypophosphatemia is often accompanied by malaise, bone pain, muscular weakness, and bone fractures. Osteomalacia due to aluminum deposition may present in a similar fashion and occurs predominantly in patients with chronic renal failure. Aluminum deposits are seen on bone biopsy.[Ref]

Nervous system

Encephalopathy associated with aluminum accumulation is generally characterized by speech disorders, dysarthria, dyspraxia, dysphasia, tremor, myoclonus, seizures, coma, and death. EEG of patients with aluminum encephalopathy has shown paroxysmal slowing, and diffuse rhythmical bursts of delta activity.

The interval between commencement of aluminum hydroxide therapy and development of encephalopathy in eight reported cases ranged from three weeks to three months. In two of these patients, aluminum serum concentrations ranged from 871 to 2267 mcg/L. These patients were on concomitant sodium citrate therapy. Most chronic dialysis patients develop aluminum encephalopathy slowly over several years.[Ref]

Nervous system side effects have included encephalopathy which has occasionally been reported in patients with renal failure on long-term therapy with aluminum hydroxide. When available, basal and/or deferoxamine stimulated aluminum serum levels reveal high concentrations.[Ref]

Renal

Renal side effects have rarely included formation of renal calculi, most probably due to hypercalciuria, with the use of aluminum hydroxide.[Ref]

Other

Antacids may interfere with drug therapies because of their effect on gastric pH, adsorption or binding to drugs, and changes in urinary pH.[Ref]

Some side effects of Alamag may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

Magnesium hydroxide and aluminum hydroxide have not been formally assigned to a pregnancy category by the FDA. There are no controlled data in human pregnancy. Other magnesium salts (such as magnesium sulfate) have been used extensively during pregnancy in large doses with no reports of congenital defects. Magnesium hydroxide and aluminum hydroxide should only be given in pregnancy when benefit outweighs risk.

In a review of 229,101 deliveries to Michigan Medicaid patients, 351 first-trimester exposures to aluminum hydroxide were recorded and 996 exposures any time during pregnancy. A total of 14 birth defects were reported with first trimester exposure (15 expected) and included (observed/expected) 5/4 cardiovascular defects, 2/0.5 oral clefts, 1 polydactyly, and 1 hypospadias. In addition, 341 first-trimester exposures to magnesium hydroxide were recorded and 974 exposures any time during pregnancy. A total of 14 birth defects were reported with first trimester exposure (14 expected) and included (observed/expected) 5/3 cardiovascular defects, 2/0.8 polydactyly, and one hypospadias. These data do not support an association between aluminum hydroxide or magnesium hydroxide ingestion and adverse fetal outcome (written communication, Franz Rosa, MD, Food and Drug Administration, 1994).