Magnesium Hydroxide
NOTE: Referenced from Lexi-Comp - View References below**
*** Not commonly used a phosphate binder due to increased magnesium accumulation and required monitoring. ****
Dosing: Adult: From studies using magnesium containing phosphate binders, start with 1 tablet three times daily with meals and titrate until serum phosphate < 1.8 mmol/L. Monitor magnesium levels.
Dosing: Renal Impairment
Patients in severe renal failure should not receive magnesium due to toxicity from accumulation. Patients with a Clcr <30 mL/minute should be monitored by serum magnesium levels.
Contraindications
Hypersensitivity to magnesium hydroxide or any component of the formulation
Warnings/Precautions
Disease-related concerns:
• Neuromuscular disease: Use with extreme caution in patients with myasthenia gravis or other neuromuscular disease.
• Renal impairment: Use with caution in patients with renal impairment; accumulation of magnesium may lead to magnesium intoxication.
Other warnings/precautions:
Geriatric Considerations
Elderly, due to disease or drug therapy, may be predisposed to diarrhea. Diarrhea may result in electrolyte imbalance. Decreased renal function (Clcr <30 mL/minute) may result in toxicity; monitor for toxicity.
Drug Interactions
ACE Inhibitors: Antacids may decrease the serum concentration of ACE Inhibitors. Management: Separate fosinopril administration from antacids by at least 2 hours. US and Canadian recommendations for use of other ACE- inhibitors with antacids may vary. Consult appropriate labeling. Monitor for decreased therapeutic effects of ACE-inhibitors. Exceptions: Enalaprilat; Ramipril. Risk D: Consider therapy modification
Allopurinol: Antacids may decrease the absorption of Allopurinol. Risk D: Consider therapy modification
Bisacodyl: Antacids may diminish the therapeutic effect of Bisacodyl. Antacids may cause the delayed-release bisacodyl tablets to release drug prior to reaching the large intestine. Gastric irritation and/or cramps may occur. Risk D: Consider therapy modification
Bisphosphonate Derivatives: Antacids may decrease the serum concentration of Bisphosphonate Derivatives. Management: Avoid administration of antacids containing polyvalent cations within: 2 hours before or after tiludronate/clodronate/etidronate; 60 minutes after oral ibandronate; or 30 minutes after alendronate/risedronate.Exceptions: Pamidronate; Zoledronic Acid. Risk D: Consider therapy modification
Calcitriol: May increase the serum concentration of Magnesium Salts. Risk D: Consider therapy modification
Calcium Polystyrene Sulfonate: Laxatives may enhance the adverse/toxic effect of Calcium Polystyrene Sulfonate. More specifically, concomitant use of calcium polystyrene sulfonate with magnesium-containing laxatives may result in metabolic alkalosis or with sorbitol may result in intestinal necrosis. Management: Avoid concomitant use of calcium polystyrene sulfonate (rectal or oral) and magnesium-containing laxatives or sorbitol. Risk X: Avoid combination
Cefuroxime: Antacids may decrease the serum concentration of Cefuroxime. Management: Consider administering antacids and cefuroxime at least 2 hours apart. Risk D: Consider therapy modification
Chloroquine: Antacids may decrease the serum concentration of Chloroquine. Management: Separate administration of antacids and chloroquine by at least 4 hours to minimize any potential negative impact of antacids on chloroquine bioavailability. Risk D: Consider therapy modification
Corticosteroids (Oral): Antacids may decrease the bioavailability of Corticosteroids (Oral). Risk D: Consider therapy modification
Dabigatran Etexilate: Antacids may decrease the serum concentration of Dabigatran Etexilate. Management: Dabigatran etexilate Canadian product labeling recommends avoiding concomitant use with antacids for 24 hours after surgery. In other situations, administer dabigatran etexilate 2 hours prior to antacids. Monitor clinical response to dabigatran therapy. Risk D: Consider therapy modification
Fexofenadine: Antacids may decrease the serum concentration of Fexofenadine. Management: No specific recommendations concerning the time required between their administration are provided. Separate administration of each agent by as much time as possible to decrease the risk of an interaction. Risk D: Consider therapy modification
Gabapentin: Antacids may decrease the serum concentration of Gabapentin. Management: Administer gabapentin at least 2 hours after antacid administration. Monitor patients closely for evidence of reduced response to gabapentin therapy when both of these drugs are being used. Risk D: Consider therapy modification
Iron Salts: Antacids may decrease the absorption of Iron Salts. Exceptions: Ferric Gluconate; Ferumoxytol; Iron Dextran Complex; Iron Sucrose. Risk D: Consider therapy modification
Itraconazole: Antacids may decrease the serum concentration of Itraconazole. Management: Administer itraconazole at least 1 hour after and 2 hours before administration of any antacids. Itraconazole oral suspension may be less sensitive to the effects of decreased gastric acidity. Risk D: Consider therapy modification
Ketoconazole (Systemic): Antacids may decrease the serum concentration of Ketoconazole (Systemic). Management: Administer oral ketoconazole at least 2 hours prior to use of any antacid product. Monitor patients closely for signs of inadequate clinical response to ketoconazole. Risk D: Consider therapy modification
Misoprostol: Antacids may enhance the adverse/toxic effect of Misoprostol. More specifically, concomitant use with magnesium-containing antacids may increase the risk of diarrhea. Management: Avoid concomitant use of misoprostol and magnesium-containing antacids. In patients requiring antacid therapy, employ magnesium-free preparations. Monitor for increased adverse effects (e.g., diarrhea, dehydration). Risk D: Consider therapy modification
Multivitamins/Minerals (with ADEK, Folate, Iron): Antacids may decrease the serum concentration of Multivitamins/Minerals (with ADEK, Folate, Iron). Specifically, antacids may decrease the absorption of orally administered iron. Management: Separate dosing of oral iron-containing multivitamin preparations and antacids by as much time as possible in order to minimize impact on therapeutic efficacy of the iron preparation. Risk D: Consider therapy modification
Mycophenolate: Antacids may decrease the absorption of Mycophenolate. Management: Separate doses of mycophenolate and antacids by at least 2 hours. Monitor for reduced effects of mycophenolate if taken concomitant with antacids. Risk D: Consider therapy modification
Phosphate Supplements: Magnesium Salts may decrease the serum concentration of Phosphate Supplements. Management: Administer oral phosphate supplements at least 1 hour before, or 2 hours after, oral magnesium salt administration. Exceptions: Potassium Phosphate. Risk D: Consider therapy modification
QuiNINE: Antacids may decrease the serum concentration of QuiNINE. Risk X: Avoid combination
Quinolone Antibiotics: Magnesium Salts may decrease the absorption of Quinolone Antibiotics. Of concern only with oral administration of both agents. Risk D: Consider therapy modification
Sodium Polystyrene Sulfonate: Laxatives may enhance the adverse/toxic effect of Sodium Polystyrene Sulfonate. More specifically, concomitant use of sodium polystyrene sulfonate with magnesium-containing laxatives may result in metabolic alkalosis or with sorbitol may result in intestinal necrosis. Management: Avoid concomitant use of sodium polystyrene sulfonate (rectal or oral) and magnesium-containing laxatives or sorbitol. Risk X: Avoid combination
Tetracycline Derivatives: Magnesium Salts may decrease the absorption of Tetracycline Derivatives. Only applicable to oral preparations of each agent. Risk D: Consider therapy modification
Monitoring Parameters
Monitor magnesium levels every 2 weeks upon initiation and dose adjustment. Once stable, monitor monthly. If magnesium levels rise, discontinue phosphate binder as may lead to hypermagnesemia.
Mechanism of Action
Binds the phosphate in dietary food and is excreted in the faeces prior to absorption.
Pharmacodynamics/Kinetics
Excretion: Urine (up to 30% as absorbed magnesium ions); feces (as unabsorbed drug)
*** Not commonly used a phosphate binder due to increased magnesium accumulation and required monitoring. ****
Dosing: Adult: From studies using magnesium containing phosphate binders, start with 1 tablet three times daily with meals and titrate until serum phosphate < 1.8 mmol/L. Monitor magnesium levels.
Dosing: Renal Impairment
Patients in severe renal failure should not receive magnesium due to toxicity from accumulation. Patients with a Clcr <30 mL/minute should be monitored by serum magnesium levels.
Contraindications
Hypersensitivity to magnesium hydroxide or any component of the formulation
Warnings/Precautions
Disease-related concerns:
• Neuromuscular disease: Use with extreme caution in patients with myasthenia gravis or other neuromuscular disease.
• Renal impairment: Use with caution in patients with renal impairment; accumulation of magnesium may lead to magnesium intoxication.
Other warnings/precautions:
Geriatric Considerations
Elderly, due to disease or drug therapy, may be predisposed to diarrhea. Diarrhea may result in electrolyte imbalance. Decreased renal function (Clcr <30 mL/minute) may result in toxicity; monitor for toxicity.
Drug Interactions
ACE Inhibitors: Antacids may decrease the serum concentration of ACE Inhibitors. Management: Separate fosinopril administration from antacids by at least 2 hours. US and Canadian recommendations for use of other ACE- inhibitors with antacids may vary. Consult appropriate labeling. Monitor for decreased therapeutic effects of ACE-inhibitors. Exceptions: Enalaprilat; Ramipril. Risk D: Consider therapy modification
Allopurinol: Antacids may decrease the absorption of Allopurinol. Risk D: Consider therapy modification
Bisacodyl: Antacids may diminish the therapeutic effect of Bisacodyl. Antacids may cause the delayed-release bisacodyl tablets to release drug prior to reaching the large intestine. Gastric irritation and/or cramps may occur. Risk D: Consider therapy modification
Bisphosphonate Derivatives: Antacids may decrease the serum concentration of Bisphosphonate Derivatives. Management: Avoid administration of antacids containing polyvalent cations within: 2 hours before or after tiludronate/clodronate/etidronate; 60 minutes after oral ibandronate; or 30 minutes after alendronate/risedronate.Exceptions: Pamidronate; Zoledronic Acid. Risk D: Consider therapy modification
Calcitriol: May increase the serum concentration of Magnesium Salts. Risk D: Consider therapy modification
Calcium Polystyrene Sulfonate: Laxatives may enhance the adverse/toxic effect of Calcium Polystyrene Sulfonate. More specifically, concomitant use of calcium polystyrene sulfonate with magnesium-containing laxatives may result in metabolic alkalosis or with sorbitol may result in intestinal necrosis. Management: Avoid concomitant use of calcium polystyrene sulfonate (rectal or oral) and magnesium-containing laxatives or sorbitol. Risk X: Avoid combination
Cefuroxime: Antacids may decrease the serum concentration of Cefuroxime. Management: Consider administering antacids and cefuroxime at least 2 hours apart. Risk D: Consider therapy modification
Chloroquine: Antacids may decrease the serum concentration of Chloroquine. Management: Separate administration of antacids and chloroquine by at least 4 hours to minimize any potential negative impact of antacids on chloroquine bioavailability. Risk D: Consider therapy modification
Corticosteroids (Oral): Antacids may decrease the bioavailability of Corticosteroids (Oral). Risk D: Consider therapy modification
Dabigatran Etexilate: Antacids may decrease the serum concentration of Dabigatran Etexilate. Management: Dabigatran etexilate Canadian product labeling recommends avoiding concomitant use with antacids for 24 hours after surgery. In other situations, administer dabigatran etexilate 2 hours prior to antacids. Monitor clinical response to dabigatran therapy. Risk D: Consider therapy modification
Fexofenadine: Antacids may decrease the serum concentration of Fexofenadine. Management: No specific recommendations concerning the time required between their administration are provided. Separate administration of each agent by as much time as possible to decrease the risk of an interaction. Risk D: Consider therapy modification
Gabapentin: Antacids may decrease the serum concentration of Gabapentin. Management: Administer gabapentin at least 2 hours after antacid administration. Monitor patients closely for evidence of reduced response to gabapentin therapy when both of these drugs are being used. Risk D: Consider therapy modification
Iron Salts: Antacids may decrease the absorption of Iron Salts. Exceptions: Ferric Gluconate; Ferumoxytol; Iron Dextran Complex; Iron Sucrose. Risk D: Consider therapy modification
Itraconazole: Antacids may decrease the serum concentration of Itraconazole. Management: Administer itraconazole at least 1 hour after and 2 hours before administration of any antacids. Itraconazole oral suspension may be less sensitive to the effects of decreased gastric acidity. Risk D: Consider therapy modification
Ketoconazole (Systemic): Antacids may decrease the serum concentration of Ketoconazole (Systemic). Management: Administer oral ketoconazole at least 2 hours prior to use of any antacid product. Monitor patients closely for signs of inadequate clinical response to ketoconazole. Risk D: Consider therapy modification
Misoprostol: Antacids may enhance the adverse/toxic effect of Misoprostol. More specifically, concomitant use with magnesium-containing antacids may increase the risk of diarrhea. Management: Avoid concomitant use of misoprostol and magnesium-containing antacids. In patients requiring antacid therapy, employ magnesium-free preparations. Monitor for increased adverse effects (e.g., diarrhea, dehydration). Risk D: Consider therapy modification
Multivitamins/Minerals (with ADEK, Folate, Iron): Antacids may decrease the serum concentration of Multivitamins/Minerals (with ADEK, Folate, Iron). Specifically, antacids may decrease the absorption of orally administered iron. Management: Separate dosing of oral iron-containing multivitamin preparations and antacids by as much time as possible in order to minimize impact on therapeutic efficacy of the iron preparation. Risk D: Consider therapy modification
Mycophenolate: Antacids may decrease the absorption of Mycophenolate. Management: Separate doses of mycophenolate and antacids by at least 2 hours. Monitor for reduced effects of mycophenolate if taken concomitant with antacids. Risk D: Consider therapy modification
Phosphate Supplements: Magnesium Salts may decrease the serum concentration of Phosphate Supplements. Management: Administer oral phosphate supplements at least 1 hour before, or 2 hours after, oral magnesium salt administration. Exceptions: Potassium Phosphate. Risk D: Consider therapy modification
QuiNINE: Antacids may decrease the serum concentration of QuiNINE. Risk X: Avoid combination
Quinolone Antibiotics: Magnesium Salts may decrease the absorption of Quinolone Antibiotics. Of concern only with oral administration of both agents. Risk D: Consider therapy modification
Sodium Polystyrene Sulfonate: Laxatives may enhance the adverse/toxic effect of Sodium Polystyrene Sulfonate. More specifically, concomitant use of sodium polystyrene sulfonate with magnesium-containing laxatives may result in metabolic alkalosis or with sorbitol may result in intestinal necrosis. Management: Avoid concomitant use of sodium polystyrene sulfonate (rectal or oral) and magnesium-containing laxatives or sorbitol. Risk X: Avoid combination
Tetracycline Derivatives: Magnesium Salts may decrease the absorption of Tetracycline Derivatives. Only applicable to oral preparations of each agent. Risk D: Consider therapy modification
Monitoring Parameters
Monitor magnesium levels every 2 weeks upon initiation and dose adjustment. Once stable, monitor monthly. If magnesium levels rise, discontinue phosphate binder as may lead to hypermagnesemia.
Mechanism of Action
Binds the phosphate in dietary food and is excreted in the faeces prior to absorption.
Pharmacodynamics/Kinetics
Excretion: Urine (up to 30% as absorbed magnesium ions); feces (as unabsorbed drug)
References
Chernow B, Smith J, Rainey TG, et al, “Hypomagnesemia: Implications for the Critical Care Specialist,” Crit Care Med, 1982, 10(3):193-6. [PubMed 7037303]
Constipation Guideline Committee, “Clinical Practice Guideline. Evaluation and Treatment of Constipation of Infants and Children: Recommendations of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition,” J Pediatr Gastroenterol Nutr, 2006, 43(3):e1-13.[PubMed 16954945]
Gams JG, “Clinical Significance of Magnesium: A Review,” Drug Intell Clin Pharm, 1987, 21(3):240-6.[PubMed 3552543]
Idama TO and Lindow SW, "Magnesium Sulphate: A Review of Clinical Pharmacology Applied to Obstetrics," Br J Obstet Gynaecol, 1998, 105(3):260-8.[PubMed 9532984]
Institute of Medicine (IOM), Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride, National Academy of Sciences, Washington, DC, 1997.
Mahadevan U and Kane S, "American Gastroenterological Association Institute Medical Position Statement on the Use of Gastrointestinal Medications in Pregnancy,"Gastroenterology, 2006, 131(1):278-82. [PubMed 16831610]
Osada H, Watanabe Y, Nishimura Y, et al, "Profile of Trace Element Concentrations in the Feto-placental Unit in Relation to Fetal Growth," Acta Obstet Gynecol Scand, 2002, 81(10):931-7.[PubMed 12366483]
Chernow B, Smith J, Rainey TG, et al, “Hypomagnesemia: Implications for the Critical Care Specialist,” Crit Care Med, 1982, 10(3):193-6. [PubMed 7037303]
Constipation Guideline Committee, “Clinical Practice Guideline. Evaluation and Treatment of Constipation of Infants and Children: Recommendations of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition,” J Pediatr Gastroenterol Nutr, 2006, 43(3):e1-13.[PubMed 16954945]
Gams JG, “Clinical Significance of Magnesium: A Review,” Drug Intell Clin Pharm, 1987, 21(3):240-6.[PubMed 3552543]
Idama TO and Lindow SW, "Magnesium Sulphate: A Review of Clinical Pharmacology Applied to Obstetrics," Br J Obstet Gynaecol, 1998, 105(3):260-8.[PubMed 9532984]
Institute of Medicine (IOM), Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride, National Academy of Sciences, Washington, DC, 1997.
Mahadevan U and Kane S, "American Gastroenterological Association Institute Medical Position Statement on the Use of Gastrointestinal Medications in Pregnancy,"Gastroenterology, 2006, 131(1):278-82. [PubMed 16831610]
Osada H, Watanabe Y, Nishimura Y, et al, "Profile of Trace Element Concentrations in the Feto-placental Unit in Relation to Fetal Growth," Acta Obstet Gynecol Scand, 2002, 81(10):931-7.[PubMed 12366483]