Professional Information
Antacids (Oral-Local)
1) Alumina, Calcium Carbonate, and Sodium Bicarbonate *
2) Alumina and Magnesia
3) Alumina, Magnesia, Calcium Carbonate, and Simethicone †
4) Alumina, Magnesia, and Magnesium Carbonate *
5) Alumina, Magnesia, Magnesium Carbonate, and Simethicone *
6) Alumina, Magnesia, and Simethicone
7) Alumina, Magnesium Alginate, and Magnesium Carbonate *
8) Alumina and Magnesium Carbonate †
9) Alumina, Magnesium Carbonate, and Simethicone †
10) Alumina, Magnesium Carbonate, and Sodium Bicarbonate †
11) Alumina and Magnesium Trisilicate †
12) Alumina, Magnesium Trisilicate, and Sodium Bicarbonate †
13) Alumina and Simethicone †
14) Alumina and Sodium Bicarbonate *
15) Aluminum Carbonate, Basic †
16) Aluminum Carbonate, Basic, and Simethicone †
17) Aluminum Hydroxide
18) Calcium Carbonate ‡
19) Calcium Carbonate and Magnesia
20) Calcium Carbonate, Magnesia, and Simethicone
21) Calcium Carbonate and Simethicone †
22) Calcium and Magnesium Carbonates
23) Magaldrate
24) Magaldrate and Simethicone
25) Magnesium Carbonate and Sodium Bicarbonate *
26) Magnesium Hydroxide §
27) Magnesium Oxide § †
VA CLASSIFICATION
Alumina, Calcium Carbonate, and Sodium Bicarbonate
Primary: GA199
Alumina and Magnesia
Primary: GA103
Alumina, Magnesia, Calcium Carbonate, and Simethicone
Primary: GA199
Alumina, Magnesia, and Magnesium Carbonate
Primary: GA103
Alumina, Magnesia, Magnesium Carbonate, and Simethicone
Primary: GA199
Alumina, Magnesia, and Simethicone
Primary: GA199
Alumina, Magnesium Alginate, and Magnesium Carbonate
Primary: GA103
Alumina and Magnesium Carbonate
Primary: GA103
Alumina, Magnesium Carbonate, and Simethicone
Primary: GA199
Alumina, Magnesium Carbonate, and Sodium Bicarbonate
Primary: GA104
Alumina and Magnesium Trisilicate
Primary: GA103
Alumina, Magnesium Trisilicate, and Sodium Bicarbonate
Primary: GA104
Alumina and Simethicone
Primary: GA199
Alumina and Sodium Bicarbonate
Primary: GA199
Aluminum Carbonate, Basic
Primary: GA101
Secondary: GU900
Aluminum Carbonate, Basic, and Simethicone
Primary: GA199
Aluminum Hydroxide
Primary: GA101
Secondary: GA208; GU900
Calcium Carbonate
Primary: GA105
Secondary: TN402
Calcium Carbonate and Magnesia
Primary: GA106
Calcium Carbonate, Magnesia, and Simethicone
Primary: GA199
Calcium Carbonate and Simethicone
Primary: GA199
Calcium and Magnesium Carbonates
Primary: GA106
Magaldrate
Primary: GA107
Magaldrate and Simethicone
Primary: GA199
Magnesium Carbonate and Sodium Bicarbonate
Primary: GA109
Magnesium Hydroxide
Primary: GA108
Secondary: GA202; GU900
Magnesium Oxide
Primary: GA108
Secondary: GA202
‡ See Calcium Supplements (Systemic) for systemic use of calcium carbonate in hypocalcemia
§ See Laxatives (Local) for laxative use of magnesium hydroxide and magnesium oxide
Note: For a listing of dosage forms and brand names by country availability, see Dosage Forms section(s).
*Not commercially available in the U.S.
†Not commercially available in Canada.
Category:
Antacid—All drugs included in this monograph are used as antacids;
Antiurolithic (phosphate calculi)—Aluminum Carbonate; Aluminum Hydroxide;
Laxative, hyperosmotic, saline—Magnesium Hydroxide; Magnesium Oxide (see Magnesium Hydroxide and Magnesium Oxide, Laxatives [Local] );
Antihyperphosphatemic—Aluminum Carbonate; Aluminum Hydroxide; Calcium Carbonate (see Calcium Carbonate, Calcium Supplements [Systemic] );
Antihypocalcemic—Calcium Carbonate (see Calcium Carbonate, Calcium Supplements [Systemic] );
Antiurolithic (calcium calculi)—Magnesium Hydroxide;
Indications
Note: Bracketed information in the Indications section refers to uses that are not included in U.S. product labeling.
Accepted
Hyperacidity (treatment)
Ulcer, duodenal (treatment) or
Ulcer, gastric (treatment)—Antacids are indicated for relief of symptoms associated with hyperacidity (heartburn, acid indigestion, and sour stomach). In addition, antacids are used in hyperacidity associated with gastric and duodenal ulcers. However, there have been reports of increased gastrin levels and increased gastric secretion (acid rebound) associated with the use of antacids. {15} {31} {87}
—Some of the antacid combinations contain other ingredients that have no antacid properties. Simethicone, an antiflatulent, has been added as an aid in those conditions in which the retention of gas may be a problem; however, in the treatment of peptic ulcer diseases, the advantage of using antacid and simethicone combinations rather than antacids alone has not been clearly established. {31}
Hypersecretory conditions, gastric (treatment adjunct)
Zollinger-Ellison syndrome (treatment adjunct)
Mastocytosis, systemic (treatment adjunct) or
Adenoma, multiple endocrine (treatment adjunct)—Antacids are indicated in conjunction with histamine H 2-receptor antagonists or omeprazole for transient symptomatic relief in the treatment of pathological gastric hypersecretion associated with Zollinger-Ellison syndrome (alone or as part of multiple endocrine neoplasia Type-I), systemic mastocytosis, and multiple endocrine adenoma. {35}
Reflux, gastroesophageal (treatment)—Antacids are indicated in the symptomatic treatment of gastroesophageal reflux disease. {05} {28} {31} {87}
Stress-related mucosal damage (prophylaxis and treatment)—Antacids are indicated to prevent and treat upper gastrointestinal, stress-induced ulceration and bleeding, especially in intensive care patients. {69} {82} {98} {99} {100}
[Hyperphosphatemia (treatment)]1—Aluminum carbonate and aluminum hydroxide may be used in conjunction with a low-phosphate diet to reduce elevated phosphate levels and demineralization of bones in patients with renal insufficiency. {31} However, use of aluminum-containing antacids as phosphate binders may lead to aluminum toxicity in patients with renal insufficiency. {77} {89} {90} Other agents may be preferable for treating hyperphosphatemia in patients with renal insufficiency.
Hypocalcemia (treatment)—See Calcium Carbonate, Calcium Supplements (Systemic) . {23}
—[Aluminum hydroxide has been used in the treatment of neonatal hypocalcemia and diarrhea; however, it generally has been replaced by other agents. Aluminum carbonate and aluminum hydroxide have been used along with a low-phosphate diet to prevent formation of phosphatic (struvite) urinary stones; however, their use has been replaced by other agents.{104} Magnesium hydroxide has been used to prevent recurrence of calcium stones; however, it has been replaced by other agents.{104} Use of aluminum-containing antacids in young children and premature infants may lead to aluminum toxicity, especially in those patients with renal failure.{46}{76}{77}]1
Unaccepted
Antacids have been used in patients undergoing anesthesia or during labor to lessen the danger from aspiration of gastric contents. However, the use of antacids to prevent acid aspiration has generally been replaced by the equally or more effective histamine H 2-receptor antagonists or citrate solutions. {07} {42}
1 Not included in Canadian product labeling.
Pharmacology/Pharmacokinetics
Physicochemical characteristics:
Molecular weight—
Aluminum hydroxide: 78
Calcium carbonate: 100.09
Magnesium hydroxide: 58.32
Magnesium oxide: 40.30
Sodium bicarbonate: 84.01
Mechanism of action/Effect:
Antacid—These medications react chemically to neutralize or buffer existing quantities of stomach acid but have no direct effect on its output. This action results in increased pH value of stomach contents, thus providing relief of hyperacidity symptoms. Also, these medications reduce acid concentration within the lumen of the esophagus. This causes an increase in intra-esophageal pH and a decrease in pepsin activity. {69}
Antiurolithic—Aluminum carbonate and aluminum hydroxide bind phosphate ions in the intestine to form insoluble aluminum phosphate, which is excreted in the feces. {69} They thereby reduce phosphates in the urine and prevent formation of phosphatic (struvite) urinary stones. Magnesium hydroxide inhibits the precipitation of calcium oxalate and calcium phosphate, thus preventing the formation of calcium stones.
Antihyperphosphatemic—Aluminum carbonate and aluminum hydroxide reduce serum phosphate levels by binding with phosphate ions in the intestine to form insoluble aluminum phosphate, which passes through the intestinal tract unabsorbed. {69}
Antihypocalcemic—Aluminum hydroxide may increase the release of calcium from bone {68} as a result of the decreased serum phosphate levels.
Antidiarrheal—Aluminum hydroxide's constipating {101} properties help decrease the fluidity of stools.
Other actions/effects:
Antacids may increase lower esophageal sphincter (LES) pressure. {05} Aluminum-containing antacids have a cytoprotective effect on the gastric mucosa that may be associated with the stimulation of prostaglandin secretion, thus providing protection against mucosal necrosis and hemorrhage caused by corrosive agents, such as aspirin and ethanol. {91} {92}
Absorption:
Aluminum-containing—Small amounts of the aluminum in aluminum hydroxide are absorbed from the intestine. {93}
Calcium-containing—Approximately 15% of the calcium in calcium carbonate is absorbed from the intestine in normal persons. {93} The amount of calcium absorbed from the gastrointestinal tract is determined by hormonal factors, particularly parathyroid hormone, and vitamin D. {93}
Magnesium-containing—Approximately 10% of the magnesium in magnesium hydroxide (magnesia) is absorbed from the intestine.
Onset and duration of action
Onset of action is dependent upon the ability of the antacid to solubilize in the stomach and react with the hydrochloric acid. {69} The poorly soluble antacids (e.g., magnesium trisilicate) {69} will thus react more slowly with hydrochloric acid than will the more soluble ones. In most cases with slow-acting antacids, the onset of action is delayed and may not take place if gastric emptying is rapid. {31}
Duration of action is determined primarily by gastric emptying time. Depending on the kind of antacid used, the duration of action in fasting patients may range from 20 to 60 minutes. {69} However, when the antacid is given 1 hour after meals, the acid-neutralizing effect may be prolonged up to 3 hours. {69}
The following table provides a relative comparison of onset and duration of action of different antacids.
| Antacid |
Onset of action |
Duration of action |
|---|---|---|
| Aluminum Carbonate |
Slow |
Short |
| Aluminum Hydroxide |
Slow |
Prolonged * |
| Aluminum Phosphate |
Slow |
Short |
| Calcium Carbonate |
Fast |
Prolonged |
| Magaldrate |
Intermediate |
Prolonged |
| Magnesium Carbonate |
Intermediate |
Short |
| Magnesium Hydroxide |
Fast |
Short |
| Magnesium Oxide |
Fast |
Short |
| Magnesium Trisilicate |
Slow |
Prolonged † |
| Sodium Bicarbonate |
Fast |
Short |
† If gastric emptying is rapid, stomach may empty before much of the acid is neutralized
Elimination:
Renal and fecal; {69} {93} 15 to 30% of the salts formed are absorbed and are then excreted by the kidneys. {69}
Precautions to Consider
Pregnancy/Reproduction
Pregnancy—
Antacids are generally considered safe as long as chronic high doses are avoided. {40}
Aluminum-, calcium-, or magnesium-containing antacids
Adequate and well-controlled studies in humans have not been done; however, there have been reports of antacids causing such adverse effects as hypercalcemia, hypomagnesemia, hypermagnesemia, and increased tendon reflexes in fetuses and/or neonates whose mothers were chronic users of aluminum-, calcium-, and/or magnesium-containing antacids, especially in high doses.
Studies have not been done in animals.
Sodium bicarbonate–containing antacids
Problems in humans have not been documented; however, risk-benefit must be considered because sodium bicarbonate is absorbed systemically. Chronic use may lead to systemic alkalosis. {93} The sodium load that is absorbed can also cause edema and weight gain.
Breast-feeding
Problems in humans have not been documented; although some aluminum, calcium, and magnesium may be distributed into breast milk, the concentration is not great enough to produce an effect in the neonate. {41}
Pediatrics
Antacids should not be given to young children (up to 6 years of age) unless prescribed by a physician. Since children are not usually able to describe their symptoms precisely, proper diagnosis should precede the use of an antacid. This will avoid the complication of an existing condition (e.g., appendicitis) or the appearance of severe adverse effects.
Use of magnesium-containing antacids is contraindicated in very young children {102} because there is a risk of hypermagnesemia {94}, especially in dehydrated children or children with renal failure. {68}
Use of aluminum-containing antacids is contraindicated in very young children {102} because there is a risk of aluminum toxicity, especially in dehydrated infants and children or infants and children with renal failure. {76} {77}
Geriatrics
Metabolic bone disease commonly seen in the elderly may be aggravated by the phosphorus depletion {30}, hypercalciuria, and inhibition of absorption of intestinal fluoride caused by the chronic use of aluminum-containing antacids. {79} Also, elderly patients are more likely to have age-related renal function impairment, which may lead to aluminum retention. {67} {102}
Although it is not known whether high intake of aluminum leads to Alzheimer's disease, the use of aluminum-containing antacids in Alzheimer's patients is not generally recommended. Research suggests that aluminum may contribute to the disease's development since it has been found to concentrate in neurofibrillary tangles in brain tissue. {46} {80} {83}
Drug interactions and/or related problems
The following drug interactions and/or related problems have been selected on the basis of their potential clinical significance (possible mechanism in parentheses where appropriate)—not necessarily inclusive (» = major clinical significance):
Table 1. Drug Interactions and/or Related Problems
| The following drug interactions and/or related problems have been selected on the basis of their potential clinical significance (possible mechanism in parentheses where appropriate)—not necessarily inclusive: (» = major clinical significance) Note: Combinations containing any of the following medications, depending on the amount present, may also interact with this medication. Only specific interactions between antacids and other oral medications have been identified in this monograph. However, because of antacids" ability to change gastric or urinary pH and to adsorb or form complexes with other drugs, the rate and/or extent of absorption of other medications may be increased or reduced when the medication is used concurrently with antacids {69}. In general, patients should be advised not to take any other oral medications within 1 to 2 hours of antacids. |
Legend: I=Aluminum-containing II =Calcium-containing III=Magaldrate IV=Magnesium-containing V=Sodium Bicarbonate– containing |
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|---|---|---|---|---|---|
| I |
II |
III |
IV |
V |
|
| Acidifiers, urinary, such as: Ammonium chloride Ascorbic acid Potassium or sodium phosphates Racemethionine (antacids may alkalinize the urine and counteract the effect of urinary acidifiers; frequent use of antacids, especially in high doses, is best avoided by patients receiving therapy to acidify the urine) |
 |
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|
|
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| Amphetamines or {63} Quinidine (urinary excretion may be inhibited when these medications are used concurrently with antacids in doses that cause the urine to become alkaline, possibly resulting in toxicity; dosage adjustment may be needed when therapy with these antacids is initiated or discontinued or if dosage is changed) {09} {21} {27} {63} {64} |
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|
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| Anticholinergics or other medications with anticholinergic activity (See Appendix II ) (concurrent use with antacids may decrease absorption, reducing the effectiveness of anticholinergics; doses of these medications should be spaced 1 hour apart from doses of antacids) {63} {68} {69} |
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| (urinary excretion may be delayed by alkalinization of the urine, thus potentiating the side effects of the anticholinergic) |
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|
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| Calcitonin or Etidronate {70} or Gallium nitrate {47} or Pamidronate {108} or Plicamycin (concurrent use with calcium carbonate may antagonize the effect of these medications in the treatment of hypercalcemia) {12} |
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| Calcium-containing preparations (concurrent and prolonged use with sodium bicarbonate may result in the milk-alkali syndrome) {48} {56} {57} {65} |
|
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| » Cellulose sodium phosphate {16} (concurrent use with calcium-containing antacids may decrease effectiveness of cellulose sodium phosphate in preventing hypercalciuria) |
|
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| (concurrent use with magnesium-containing antacids may result in binding of magnesium; patients should be advised not to take these medications within 1 hour of cellulose sodium phosphate) |
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| Chenodiol (concurrent use with aluminum-containing antacids may result in binding of chenodiol, thus decreasing its absorption) {17} |
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| Citrates (concurrent use with antacids containing aluminum, calcium carbonates, magaldrate, or sodium bicarbonate may result in systemic alkalosis) |
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| (concurrent use of sodium citrate with sodium bicarbonate may promote the development of calcium stones in patients with uric acid stones, due to sodium ion opposition to the hypocalciuric effect of the alkaline load; may also cause hypernatremia) {36} |
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| (concurrent use of aluminum-containing antacids and magaldrate with citrate salts can increase aluminum absorption, possibly resulting in acute aluminum toxicity, especially in patients with renal insufficiency) {13} {37} {38} {39} |
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| Digitalis glycosides (concurrent use with aluminum- and magnesium-containing antacids may inhibit absorption, possibly decreasing plasma concentrations of digitalis glycosides; although actual clinical importance of this interaction has not been established, it is recommended that doses of antacids and digitalis glycosides be separated by several hours) {09} {27} |
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| Diuretics, potassium-depleting, such as bumetanide, ethacrynic acid, furosemide, indapamide, thiazide diuretics {27} (concurrent use of thiazide diuretics with large doses of calcium carbonate may result in hypercalcemia) |
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| Enteric-coated medications, such as bisacodyl (concurrent administration of antacids with enteric-coated medications may cause the enteric coating to dissolve too rapidly, resulting in gastric or duodenal irritation) {10} |
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| Ephedrine (urine alkalinization induced by sodium bicarbonate may increase the half-life of ephedrine and prolong its duration of action, especially if the urine remains alkaline for several days or longer; dosage adjustment of ephedrine may be necessary) {01} {21} |
|
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| » Fluoroquinolones {06} {14} {19} {20} {53} {74} {85} {88} (alkalinization of the urine may reduce the solubility of ciprofloxacin and norfloxacin in the urine, especially when the urinary pH exceeds 7.0; if antacids and one of these medications are used concurrently, patients should be observed for signs of crystalluria and nephrotoxicity) |
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| (aluminum- and magnesium-containing antacids may reduce absorption of fluoroquinolones, resulting in lower serum and urine concentrations of these medications; therefore, concurrent use is not recommended; however, if aluminum- and magnesium-containing antacids must be used concurrently with these medications, it is recommended that enoxacin be taken at least 2 hours before or 8 hours after the antacid; ciprofloxacin and lomefloxacin should be taken at least 2 hours before or 6 hours after the antacid; and norfloxacin and ofloxacin should be taken at least 2 hours before or after the antacid) |
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| Folic acid (prolonged use of aluminum- and/or magnesium-containing antacids may decrease folic acid absorption by raising the pH of the small intestine; patients should be advised to take antacids at least 2 hours after folic acid) {73} {75} |
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| Histamine H 2-receptor antagonists (concurrent use with antacids may be indicated in the treatment of peptic ulcer to relieve pain; however, simultaneous administration of medium to high doses [80 mmol to 150 mmol] of antacids is not recommended since absorption of histamine H 2-receptor antagonists may be decreased; patients should be advised not to take any antacids within 1/2 to 1 hour of histamine H 2-receptor antagonists) {09} {18} {21} {53} {59} |
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| Iron preparations, oral (absorption may be decreased when these preparations are used concurrently with magnesium trisilicate or antacids containing carbonate; spacing the doses of the iron preparation as far as possible from doses of the antacid is recommended) {09} {21} {27} {53} |
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| » Isoniazid, oral (concurrent use with aluminum-containing antacids may delay and decrease absorption of oral isoniazid; concurrent use should be avoided or the patient should be advised to take oral isoniazid at least 1 hour before the antacid) {09} {21} {27} |
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| » Ketoconazole (antacids may cause increased gastrointestinal pH; concurrent administration with antacids may result in a marked reduction in absorption of ketoconazole; patients should be advised to take antacids at least 3 hours after ketoconazole) {10} {21} |
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| Lithium (sodium bicarbonate enhances lithium excretion, possibly resulting in decreased efficacy; this may be partly due to the sodium content) {02} {03} {04} {21} |
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| Mexiletine (marked alkalinization of the urine caused by sodium bicarbonate may slow renal excretion of mexiletine) {21} |
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| » Mecamylamine (alkalinization of the urine may slow excretion and prolong the effects of mecamylamine; concurrent use is not recommended) {24} |
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| » Methenamine (concurrent use with antacids that cause the urine to become alkaline may reduce the effectiveness of methenamine by inhibiting its conversion to formaldehyde; concurrent use is not recommended) {84} |
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| Milk or milk products (concurrent and prolonged use with calcium carbonate or sodium bicarbonate may result in the milk-alkali syndrome) {48} {56} {57} |
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| Misoprostol (concurrent use with magnesium-containing antacids may aggravate misoprostol-induced diarrhea) {46} |
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| Pancrelipase (concurrent administration of antacids may be required to prevent inactivation of pancrelipase [except enteric-coated dosage forms] {95} by gastric pepsin and acid pH; however, calcium carbonate– and/or magnesium-containing antacids are not recommended since they may decrease the effectiveness of pancrelipase) {26} |
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| Penicillamine (absorption may be reduced when penicillamine is administered concurrently with aluminum- or magnesium-containing antacids; although more studies are needed to establish the significance of this interaction, it is recommended that doses of antacids and penicillamine be separated by 2 hours) {21} {44} {45} {47} |
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| Phenothiazines, especially chlorpromazine, oral (absorption may be inhibited when these medications are used concurrently with aluminum- or magnesium-containing antacids; although more studies are needed to establish the significance of this interaction, simultaneous administration should be avoided) {21} |
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| Phenytoin (concurrent use with aluminum-, magnesium-, and/or calcium carbonate–containing antacids may decrease absorption of phenytoin, thus reducing serum phenytoin concentrations; although more studies are needed to establish the significance of this interaction, it is recommended that doses of antacids and phenytoin be separated by about 2 to 3 hours) {09} {64} {71} {72} |
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| Phosphates, oral (concurrent use with aluminum- or magnesium-containing antacids may bind the phosphate and prevent its absorption) {61} {62} {65} {66} |
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| (concurrent use with calcium-containing antacids may increase potential of deposition of calcium in soft tissues if serum-ionized calcium is high) |
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| Quinine (concurrent use with aluminum-containing antacids may decrease or delay the absorption of quinine) {25} {32} |
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| Salicylates (alkalinization of the urine may increase renal salicylate excretion and lower serum salicylate levels; dosage adjustments of salicylates may be necessary when chronic high-dose antacid therapy is started or stopped, especially in patients receiving large doses of the salicylate, such as patients with rheumatoid arthritis or rheumatic fever) {21} {27} {63} |
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| Sodium bicarbonate or Vitamin D (concurrent and prolonged use with calcium carbonate may result in the milk-alkali syndrome) {22} {48} {57} {65} |
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| Sodium fluoride (concurrent use with aluminum hydroxide may decrease absorption and increase fecal excretion of fluoride) |
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| (calcium ions may complex with and inhibit absorption of fluoride) {29} {65} |
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| » Sodium polystyrene sulfonate resin (SPSR) (neutralization of gastric acid may be impaired when SPSR is used concurrently with calcium- or magnesium-containing antacids, possibly resulting in systemic alkalosis; concurrent use is not recommended) {21} {27} {58} {64} |
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| Sucralfate (concurrent use with antacids may be indicated in the treatment of duodenal ulcer to relieve pain; however, simultaneous administration is not recommended since antacids may interfere with binding of sucralfate to the mucosa; patients should be advised not to take any antacids within 1/2 hour before or after sucralfate; concurrent use with aluminum-containing antacids may cause aluminum toxicity in patients with chronic renal failure) {50} {51} |
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| » Tetracyclines, oral (absorption may be decreased when oral tetracyclines are used concurrently with antacids because of possible formation of nonabsorbable complexes and/or increase in intragastric pH; patients should be advised not to take antacids within 3 to 4 hours of tetracyclines) {09} {21} {27} {53} |
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| Vitamin D, including calcifediol and calcitriol (concurrent use with magnesium-containing antacids may result in hypermagnesemia, especially in patients with chronic renal failure) |
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| (concurrent use with calcium-containing antacids may result in hypercalcemia) {43} {67} |
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Laboratory value alterations
The following have been selected on the basis of their potential clinical significance (possible effect in parentheses where appropriate)—not necessarily inclusive (» = major clinical significance):
Table 2. Laboratory Value Alterations
| Legend: I=Aluminum-containing II=Calcium-containing III=Magaldrate IV=Magnesium-containing V=Sodium Bicarbonate– containing |
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|---|---|---|---|---|---|
| I |
II |
III |
IV |
V |
|
| With diagnostic test results » Gastric acid secretion test (concurrent use of antacids may antagonize the effect of pentagastrin and histamine in the evaluation of gastric acid secretory function; administration of antacids is not recommended on the morning of the test) |
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| Meckel"s diverticulum imaging (prior administration of aluminum-containing antacids may decrease stomach and bladder uptake of sodium pertechnetate Tc 99m and thus interfere with Meckel"s diverticulum evaluation) {33} |
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| Reticuloendothelial cell imaging of liver, spleen, or bone marrow with technetium Tc 99m sulfur colloid (high doses of aluminum-containing antacids may impair reticuloendothelial cell imaging due to the polyvalent cations that cause agglomeration of the individual colloidal particles, thus causing them to be trapped by the pulmonary capillary bed rather than by the reticuloendothelial cells of the liver, spleen, and bone marrow) {34} |
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| Skeletal imaging (prior administration of aluminum-containing antacids may result in liver uptake of technetium Tc 99m pyrophosphate due to the formation of submicroscopic precipitates) {33} {86} |
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| With physiology/laboratory test values |
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| Calcium, serum (concentrations may be increased with large doses) {68} {96} |
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| Gastrin, serum (concentrations may be increased) {31} |
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| Phosphate, serum (concentrations may be decreased by excessive and prolonged use) {27} |
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| Systemic and urinary pH (may be increased) {69} |
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|
Medical considerations/Contraindications
The medical considerations/contraindications included have been selected on the basis of their potential clinical significance (reasons given in parentheses where appropriate)— not necessarily inclusive (» = major clinical significance).
Table 3. Medical considerations/Contraindications
Note: A blank space usually signifies lack of information; it is not necessarily an indication that a given medical problem is of no concern. However, the pharmacologic similarity of these agents may suggest that if caution is required in particular medical problems for one agent, then it may be required for the others as well.
| The medical considerations/contraindications included have been selected on the basis of their potential clinical significance (reasons given in parentheses where appropriate)—not necessarily inclusive (» = major clinical significance). |
Legend: I=Aluminum-containing II =Calcium-containing III=Magaldrate IV=Magnesium-containing V=Sodium Bicarbonate– containing |
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|---|---|---|---|---|---|
| I |
II |
III |
IV |
V |
|
| Except under special circumstances, these medications should not be used when the following medical problems exist: » Hypercalcemia (increased risk of exacerbation) {93} |
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| » Intestinal obstruction {31} |
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| » Renal function impairment, severe (increased risk of hypermagnesemia) {31} |
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| Risk-benefit should be considered when the following medical problems exist: |
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| » Alzheimer"s disease (may be exacerbated) {49} {80} |
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| » Appendicitis, or symptoms of (may complicate existing condition; laxative or constipating effects may increase danger of perforation or rupture) {31} |
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| Bleeding, gastrointestinal or rectal, undiagnosed {31} (condition may be exacerbated) |
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| Bone fractures {31} |
* |
* |
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| » Cirrhosis of liver or |
† |
† |
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| » Congestive heart failure or |
† |
† |
|
||
| » Edema or |
† |
† |
|
||
| » Toxemia of pregnancy |
† |
† |
|
||
| (fluid retention may be increased; low-sodium antacids should be used) {68} |
|||||
| Colitis, ulcerative (may be aggravated by laxative effect of magnesium-containing antacids) |
|
|
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| Colostomy or |
|
|
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| Diverticulitis or |
|
|
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| » Ileostomy (increased risk of fluid or electrolyte imbalance) |
|
|
|||
| » Constipation or |
|
|
|||
| » Fecal impaction (may be exacerbated) {31} {69} |
|
|
|||
| Diarrhea, chronic (possible increased danger of phosphate depletion with aluminum-containing antacids) {30} {78} |
|
|
|||
| (possible increased laxative effect with magnesium-containing antacids) {29} |
|
||||
| » Gastric outlet obstruction {31} |
|
|
|||
| » Hemorrhoids (may be aggravated) {31} {69} |
|
|
|||
| » Hypoparathyroidism (calcium excretion may be decreased) |
|
||||
| » Hypophosphatemia {30} {31} {49} |
* |
* |
|||
| » Renal function impairment (possible increased risk of aluminum toxicity to brain tissue, bone {67}, and parathyroid glands; possible onset of the neurological syndrome—dialysis dementia—in dialysis patients with long-term use of aluminum-containing antacids) |
|
|
|||
| (possible increased danger of milk-alkali syndrome and hypercalcemia with calcium-containing antacids) {31} {48} |
|
||||
| (possible increased danger of hypermagnesemia) {31} |
‡ |
‡ |
|||
| (may cause metabolic alkalosis) |
|
||||
| » Sarcoidosis (increased risk of hypercalcemia or renal disease) {31} |
|
||||
| Sensitivity to aluminum-, calcium-, magnesium-, simethicone-, or sodium bicarbonate–containing medications |
|
|
|
|
|
† Antacids containing more than 5 mEq (115 mg) of sodium per total daily dose should not be used without first checking with physician. The usual amount of sodium allowed in restricted diets is 3 grams or less per day
‡ In patients with renal function impairment, use of antacids containing more than 50 mEq (608 mg) of magnesium per total daily dose should be carefully considered
Patient monitoring
The following may be especially important in patient monitoring (other tests may be warranted in some patients, depending on condition; » = major clinical significance):
(
Table 4. Patient Monitoring
| Legend: I=Aluminum-containing II=Calcium-containing III=Magaldrate IV=Magnesium-containing V=Sodium Bicarbonate– containing |
|||||
|---|---|---|---|---|---|
| I |
II |
III |
IV |
V |
|
| Aluminum concentrations, serum (determinations recommended at periodic intervals for patients with impaired renal function receiving aluminum-containing antacids, to prevent aluminum toxicity) {90} |
|
||||
| Calcium concentrations, serum (determinations recommended at periodic intervals for patients, especially those with impaired renal function, who are receiving chronic therapy with aluminum-containing antacids) {96} |
|
|
|||
| (recommended weekly when calcium-containing antacids are used in large doses) {69} |
|
||||
| Phosphate concentrations, serum (determinations recommended at periodic intervals for patients, especially those with impaired renal function, who are receiving chronic therapy with aluminum-containing antacids) {27} {69} |
|
|
|||
| Potassium concentrations, serum (determinations recommended at periodic intervals for patients, especially those with impaired renal function, who are receiving antacids containing more than 25 mEq [925 mg] of potassium per daily dose) |
|
|
|
|
|
| Renal function determinations (recommended weekly in patients with renal function impairment, and whenever symptoms of hypercalcemia occur in patients receiving calcium-containing antacids in large doses) {31} |
|
||||
| (recommended at periodic intervals with long-term use of frequently repeated dosage) |
|
|
|
|
|
Side/Adverse Effects
Table 5. Side/Adverse Effects *
| The following side/adverse effects have been selected on the basis of their potential clinical significance (possible signs and symptoms in parentheses where appropriate)—not necessarily inclusive: |
Legend: I=Aluminum-containing II=Calcium-containing III=Magaldrate IV=Magnesium-containing V=Sodium Bicarbonate– containing |
||||
|---|---|---|---|---|---|
| I |
II |
III |
IV |
V |
|
| Medical attention needed With long-term use in chronic renal failure in dialysis patients Neurotoxicity (mood or mental changes) {31} |
|
|
|||
| With large doses Fecal impaction (continuing severe constipation) {31} |
|
|
|||
| Swelling of feet or lower legs |
|
||||
| With large doses or in renal insufficiency Metabolic alkalosis (mood or mental changes; muscle pain or twitching; nervousness or restlessness; slow breathing; unpleasant taste; unusual tiredness or weakness) {29} {30} |
|
|
|||
| With long-term or prolonged use Hypercalcemia associated with milk-alkali syndrome (frequent urge to urinate; continuing headache; continuing loss of appetite; nausea or vomiting; unusual tiredness or weakness) {29} {30} {31} |
† |
|
|||
| Osteomalacia and osteoporosis due to phosphate depletion (bone pain; swelling of wrists or ankles) {29} {31} {97} |
|
‡ |
|||
| With overuse or prolonged use Renal calculi (difficult or painful urination) {08} {11} {30} |
|
§ |
|||
| With prolonged use or large doses Phosphorus depletion syndrome (continuing feeling of discomfort; continuing loss of appetite; muscle weakness; unusual weight loss) {29} {31} |
|
|
|||
| With prolonged use or large doses and/or in renal disease Hypermagnesemia or other electrolyte imbalance (dizziness or lightheadedness; irregular heartbeat; mood or mental changes; unusual tiredness or weakness) {31} |
|
|
|||
| Medical attention needed only if continuing or bothersome |
|||||
| Chalky taste {31} |
M |
M |
M |
M |
U |
| Constipation, mild {31} {105} {106} {107} |
M |
L |
U |
U |
U |
| Diarrhea or laxative effect—with overdose {31} |
U |
U |
U |
M |
U |
| Increased thirst |
U |
U |
U |
U |
L |
| Nausea or vomiting {31} |
L |
U |
U |
L |
U |
| Speckling or whitish discoloration of stools (concentrations of fatty acid–salts of aluminum) |
L |
U |
U |
U |
U |
| Stomach cramps {31} |
M |
U |
U |
L |
L |
† May also occur with large doses and/or in chronic renal failure with calcium carbonate
‡ Osteomalacia and osteoporosis have been reported after chronic ingestion of large doses of aluminum hydroxide–containing antacids. {30} {79} Since magaldrate is converted to aluminum and magnesium hydroxides in vivo , it is likely that osteomalacia and osteoporosis may occur with excessive use of magaldrate
§ Chronic administration of magnesium trisilicate may infrequently produce silica renal stones.
Patient Consultation
Table 6. Patient Consultation
| As an aid to patient consultation, refer to Advice for the Patient, Antacids (Oral). In providing consultation, consider emphasizing the following selected information (» = major clinical significance): |
Legend: I =Aluminum-containing II=Calcium-containing III=Magaldrate IV =Magnesium-containing V=Sodium Bicarbonate– containing |
||||
|---|---|---|---|---|---|
| I |
II |
III |
IV |
V |
|
| Before using this medication |
|||||
| » Conditions affecting use, especially: Sensitivity to aluminum-, calcium-, magnesium-, simethicone-, or sodium bicarbonate–containing medication |
|
|
|
|
|
| Pregnancy—Concern for fetus or neonate only with chronic high doses; sodium intake may cause edema and weight gain (for sodium-containing) |
|
|
|
|
|
| Use in children—Not recommended for children up to 6 years of age; proper diagnosis required to avoid medical complications |
|
|
|
|
|
| Use in the elderly— Possible aggravation of metabolic bone disease |
|
||||
| Possible exacerbation of Alzheimer"s disease |
|
||||
| Other medications, especially: |
|||||
| Cellulose sodium phosphate |
|
|
|
||
| Fluoroquinolones |
|
|
|
|
|
| Isoniazid, oral |
|
|
|||
| Ketoconazole |
|
|
|
|
|
| Mecamylamine |
|
|
|
|
|
| Methenamine |
|
|
|
|
|
| Sodium polystyrene sulfonate resin |
|
|
|
||
| Tetracyclines, oral |
|
|
|
|
|
| Other medical problems, especially: Alzheimer"s disease |
|
|
|||
| Appendicitis, symptoms of |
|
|
|
|
|
| Constipation or fecal impaction or intestinal obstruction |
|
|
|||
| Edematous conditions |
|
|
|
||
| Hemorrhoids |
|
|
|||
| Hypercalcemia |
|
||||
| Hypoparathyroidism |
|
||||
| Hypophosphatemia |
|
|
|||
| Ileostomy |
|
|
|||
| Renal function impairment |
|
|
|||
| Sarcoidosis |
|
||||
| Proper use of this medication Following physician"s or manufacturer"s instructions |
|
|
|
|
|
| » Proper dosing |
|
|
|
|
|
| Missed dose: If on regular dosing schedule—Taking as soon as possible; not taking if almost time for next dose; not doubling doses |
|
|
|
|
|
| » Proper storage |
|
|
|
|
|
| For chewable tablet dosage form Chewing tablets well before swallowing for faster results and maximum effectiveness |
|
|
|
|
|
| For use in treatment of ulcers » Compliance with therapy |
|
|
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|