Version July 2025
Dosage guidance:
Dosing: 400 mg magnesium oxide = 241.3 mg elemental magnesium = 19.86 mEq elemental magnesium = 9.93 mmol elemental magnesium.
Hypomagnesemia: Limited data available. Note: Achieving optimal magnesium levels using oral therapy may be difficult due to the propensity for magnesium to cause diarrhea. IV replacement may be more appropriate, particularly in situations of severe deficit (Ref).
Infants, Children, and Adolescents: Dose expressed as elemental magnesium: Oral: 10 to 20 mg/kg/dose up to 4 times daily (Ref).
Note: Usual adult dose of magnesium oxide is 800 to 1,600 mg/day in divided doses (Ref).
There are no dosage adjustments provided in the manufacturer's labeling; however, magnesium is renally excreted. Use with caution; accumulation in renal impairment may lead to magnesium toxicity.
There are no dosage adjustments provided in the manufacturer's labeling.
(For additional information see "Magnesium oxide: Drug information")
Note: Dosages are expressed in terms of magnesium oxide salt unless otherwise specified.
Antacid: OTC labeling: Oral: 1 tablet (400 mg) twice daily; maximum: 2 tablets (800 mg)/24 hours.
Chronic idiopathic constipation (off-label use): Oral: Initial: 400 to 500 mg daily in 1 to 3 divided doses; may titrate up to 1.5 g daily based on clinical response and tolerance (Ref)
Dietary supplement: OTC labeling: Oral: 1 to 2 tablets (400 to 800 mg) daily; maximum: 2 tablets (800 mg)/24 hours.
Hypomagnesemia, treatment (off-label use):
Note: Use in asymptomatic patients only. IV magnesium therapy (ie, magnesium sulfate) is preferred in symptomatic patients with serum magnesium <1 mEq/L and in patients who have difficulty tolerating oral magnesium due to GI effects (diarrhea) (Ref). General guidance is provided below, but treatment recommendations vary; refer to institutional protocols.
Oral: 800 to 1,600 mg/day in 2 or 3 divided doses, depending on the degree of hypomagnesemia. Subsequent dosing may be based on serum magnesium concentrations (Ref).
The renal dosing recommendations are based upon the best available evidence and clinical expertise. Senior Editorial Team: Bruce Mueller, PharmD, FCCP, FASN, FNKF; Jason A. Roberts, PhD, BPharm (Hons), B App Sc, FSHP, FISAC; Michael Heung, MD, MS.
Magnesium is excreted by the kidneys. Use with caution; accumulation in kidney impairment may lead to magnesium toxicity (Ref).
Altered kidney function:
Constipation (laxative)/Antacid:
CrCl ≥60 mL/minute: Oral: No dosage adjustment necessary (Ref).
CrCl 30 to <60 mL/minute: Oral: Consider alternative agent. If used, administer doses on the low end of the recommended range and limit to occasional use only (Ref).
CrCl <30 mL/minute: Oral: Avoid use (Ref).
Dietary supplement:
CrCl ≥60 mL/minute: Oral: No dosage adjustment necessary (Ref).
CrCl 30 to <60 mL/minute: Note: The risks and benefits of magnesium supplementation in patients with stage 3 to 4 CKD have not been well studied, and conflicting results have been reported (Ref). Only use with periodic monitoring of serum magnesium and adverse effects (eg, GI) (Ref). Oral: Start with doses ~50% of the normal recommended range (eg, 200 to 400 mg/day) (Ref).
CrCl <30 mL/minute: Oral: Avoid use (Ref).
Hypomagnesemia:
CrCl ≥30 mL/minute: Oral: No dosage adjustment necessary (Ref).
CrCl 10 to <30 mL/minute: Oral: Administer 50% of the usual dose. Use with caution; frequent monitoring for hypermagnesemia is required (Ref).
CrCl <10 mL/minute: Oral: In most situations, avoid use (and address underlying cause of hypomagnesemia). If necessary, administer 25% to 50% of the usual dose with extreme caution; frequent monitoring for hypermagnesemia is required (Ref).
Augmented renal clearance (measured urinary CrCl ≥130 mL/minute/1.73 m2): Augmented renal clearance (ARC) is a condition that occurs in certain critically ill patients without organ dysfunction and with normal SCr concentrations. Younger patients (<55 years of age) admitted post trauma or major surgery are at highest risk for ARC, as well as those with sepsis, burns, or hematologic malignancies. An 8- to 24-hour measured urinary CrCl is necessary to identify these patients (Ref).
Oral: No dosage adjustment necessary. Higher doses are more likely to be necessary; adjust dose based on monitoring of magnesium concentrations (Ref).
Hemodialysis, intermittent (thrice weekly): Dialyzable (extent unknown, removal will depend on magnesium concentration in dialysate) (Ref):
Constipation (laxative)/Antacid: Oral: Avoid use (Ref).
Dietary supplement: Oral: Avoid use (Ref).
Hypomagnesemia: Oral: Address any underlying causes of hypomagnesemia, and if necessary, administer 25% to 50% of the usual dose with caution as patients with end-stage kidney disease (ESKD) may be vulnerable to developing hypermagnesemia from magnesium supplementation. Frequent monitoring for hypermagnesemia is required (Ref).
Peritoneal dialysis: Dialyzable (extent unknown, removal will depend on magnesium concentration in dialysate) (Ref):
Constipation (laxative)/Antacid: Oral: Avoid use (Ref).
Dietary supplement: Oral: Avoid use (Ref).
Hypomagnesemia: Oral: Address any underlying causes of hypomagnesemia, and if necessary, administer 25% to 50% of the usual dose with caution as patients with ESKD may be vulnerable to developing hypermagnesemia from magnesium supplementation. Frequent monitoring for hypermagnesemia is required (Ref).
CRRT:
Oral:
Constipation (laxative)/Antacid: Avoid use (Ref).
Dietary supplement: Avoid use (Ref).
Hypomagnesemia: Avoid use (Ref).
PIRRT (eg, sustained, low-efficiency diafiltration):
Oral:
Constipation (laxative)/Antacid: Avoid use (Ref).
Dietary supplement: Avoid use (Ref).
Hypomagnesemia: Avoid use (Ref).
There are no dosage adjustments provided in the manufacturer's labeling.
The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified.
Postmarketing:
Endocrine & metabolic: Hypermagnesemia (Araki 2021, Yamaguchi 2019)
Gastrointestinal: Bezoar formation (Iwamuro 2018)
Disease-related concerns:
• Acid indigestion/upset stomach (self-medication, OTC use): Appropriate use: For occasional use only; serious side effects may occur with prolonged use. For use only under the supervision of a physician in patients with kidney dysfunction or who are pregnant or breast-feeding. Unless directed by a physician, do not use for >2 weeks or exceed the recommended daily dose.
• Renal impairment: Use with caution in patients with renal impairment; accumulation of magnesium may lead to magnesium intoxication.
Multiple salt forms of magnesium exist; pay close attention to the salt form when ordering and administering magnesium; incorrect selection or substitution of one salt for another without proper dosage adjustment may result in serious over- or underdosing.
400 mg magnesium oxide = elemental magnesium 241.3 mg = magnesium 19.86 mEq = magnesium 9.93 mmol
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Tablet, Oral:
Mag-200: 200 mg [contains para-aminobenzoic acid]
Mag 440: 440 mg
MAGnesium-Oxide: 400 mg [contains soy polysaccarides]
Maox: 420 mg [contains fd&c yellow #5 (tartrazine)]
True Magnesium Oxide: 400 mg, 500 mg
Well Magnesium Oxide: 400 mg
Generic: 100 mg, 400 mg, 420 mg, 420 (252 Mg) MG
Tablet, Oral [preservative free]:
Mag-Oxide: 200 mg [corn free, gluten free, no artificial color(s), no artificial flavor(s), starch free, sugar free, wheat free, yeast free]
Generic: 500 mg
Yes
Tablets (Mag-200 Oral)
200 mg (per each): $0.07
Tablets (Mag-Oxide Oral)
200 mg (per each): $0.03
Tablets (Magnesium Oxide -Mg Supplement Oral)
400 (240 Mg) mg (per each): $0.03 - $0.08
420 (252 Mg) mg (per each): $0.05 - $0.06
500 mg (per each): $0.04
Tablets (Magnesium Oxide Oral)
400 mg (per each): $0.02 - $0.33
420 mg (per each): $0.04 - $0.11
Tablets (MAGnesium-Oxide Oral)
400 (240 Mg) mg (per each): $0.15
Tablets (Maox Oral)
420 mg (per each): $0.04
Disclaimer: A representative AWP (Average Wholesale Price) price or price range is provided as reference price only. A range is provided when more than one manufacturer's AWP price is available and uses the low and high price reported by the manufacturers to determine the range. The pricing data should be used for benchmarking purposes only, and as such should not be used alone to set or adjudicate any prices for reimbursement or purchasing functions or considered to be an exact price for a single product and/or manufacturer. Medi-Span expressly disclaims all warranties of any kind or nature, whether express or implied, and assumes no liability with respect to accuracy of price or price range data published in its solutions. In no event shall Medi-Span be liable for special, indirect, incidental, or consequential damages arising from use of price or price range data. Pricing data is updated monthly.
1,000 mg of magnesium oxide = 603.25 mg elemental magnesium = 49.64 mEq elemental magnesium.
|
Magnesium Salt |
Elemental Magnesium (mg/1,000 mg salt) |
Magnesium (mEq/1,000 mg salt) |
|---|---|---|
|
Magnesium chloride |
119.7 |
9.85 |
|
Magnesium gluconate |
54 |
4.44 |
|
Magnesium L-aspartate |
99.18 |
8.16 |
|
Magnesium oxide |
603.25 |
49.64 |
|
Magnesium sulfate |
98.7 |
8.12 |
Oral: Administer at least 2 hours apart from other medications.
Oral: Administer (preferably with food) at least 2 hours apart from other medications.
Store at controlled room temperature. Protect from moisture.
Dietary magnesium supplement (FDA approved in adults); relief of acid indigestion and upset stomach (OTC: FDA approved in adults).
None known.
Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the drug interactions program by clicking on the “Launch drug interactions program” link above.
Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the drug interactions program
Acalabrutinib: Antacids may decrease serum concentration of Acalabrutinib. Management: Separate administration of acalabrutinib capsules from the administration of any antacid by at least 2 hours in order to minimize the potential for a significant interaction. Acalabrutinib tablets are not expected to interact with antacids. Risk D: Consider Therapy Modification
Alfacalcidol: May increase serum concentration of Magnesium Salts. Management: Consider using a non-magnesium-containing antacid or phosphate-binding product in patients also receiving alfacalcidol. If magnesium-containing products must be used with alfacalcidol, serum magnesium concentrations should be monitored closely. Risk D: Consider Therapy Modification
Alpha-Lipoic Acid: Magnesium Salts may decrease absorption of Alpha-Lipoic Acid. Alpha-Lipoic Acid may decrease absorption of Magnesium Salts. Management: Separate administration of alpha-lipoic acid from that of any magnesium-containing compounds by several hours. If alpha-lipoic acid is given 30 minutes before breakfast, then administer oral magnesium-containing products at lunch or dinner. Risk D: Consider Therapy Modification
Antipsychotic Agents (Phenothiazines): Antacids may decrease absorption of Antipsychotic Agents (Phenothiazines). Risk C: Monitor
Atazanavir: Antacids may decrease absorption of Atazanavir. Management: Administer antacids 1 to 2 hours before or 2 hours after atazanavir to minimize the risk of a clinically significant interaction. Risk D: Consider Therapy Modification
Baloxavir Marboxil: Polyvalent Cation Containing Products may decrease serum concentration of Baloxavir Marboxil. Risk X: Avoid
Belumosudil: Antacids may decrease serum concentration of Belumosudil. Management: Consider separating administration of belumosudil and antacids by 2 hours and monitor for reduced belumosudil efficacy. Risk D: Consider Therapy Modification
Bictegravir: Polyvalent Cation Containing Products may decrease serum concentration of Bictegravir. Management: Administer bictegravir at least 2 hours before or 6 hours after polyvalent cation containing products. Coadministration of bictegravir with or 2 hours after most polyvalent cation products is not recommended. Risk D: Consider Therapy Modification
Bisacodyl: Antacids may decrease therapeutic effects 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. Management: Antacids should not be used within 1 hour before bisacodyl administration. Risk D: Consider Therapy Modification
Bismuth Subcitrate: Antacids may decrease therapeutic effects of Bismuth Subcitrate. Management: Avoid administration of antacids within 30 minutes of bismuth subcitrate (tripotassium bismuth dicitrate) administration. Risk D: Consider Therapy Modification
Bisphosphonate Derivatives: Polyvalent Cation Containing Products may decrease serum concentration of Bisphosphonate Derivatives. Management: Avoid administration of oral medications containing polyvalent cations within: 2 hours before or after tiludronate/clodronate/etidronate; 60 minutes after oral ibandronate; or 30 minutes after alendronate/risedronate. Risk D: Consider Therapy Modification
Bosutinib: Antacids may decrease serum concentration of Bosutinib. Management: Administer antacids more than 2 hours before or after bosutinib. Risk D: Consider Therapy Modification
Bromperidol: Antacids may decrease absorption of Bromperidol. Risk C: Monitor
Cabotegravir: Polyvalent Cation Containing Products may decrease serum concentration of Cabotegravir. Management: Administer polyvalent cation containing products at least 2 hours before or 4 hours after oral cabotegravir. Risk D: Consider Therapy Modification
Calcitriol (Systemic): May increase serum concentration of Magnesium Salts. Management: Consider using a non-magnesium-containing antacid or phosphate-binding product in patients also receiving calcitriol. If magnesium-containing products must be used with calcitriol, serum magnesium concentrations should be monitored closely. Risk D: Consider Therapy Modification
Calcium Polystyrene Sulfonate: Laxatives (Magnesium Containing) may increase adverse/toxic effects 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. Risk X: Avoid
Captopril: Antacids may decrease serum concentration of Captopril. Risk C: Monitor
Cefdinir: Antacids may decrease absorption of Cefdinir. Management: Administer cefdinir 2 hours before or 2 hours after aluminum- or magnesium-containing antacids. Risk D: Consider Therapy Modification
Cefditoren: Antacids may decrease serum concentration of Cefditoren. Risk X: Avoid
Cefpodoxime: Antacids may decrease serum concentration of Cefpodoxime. Risk C: Monitor
Cefuroxime: Antacids may decrease serum concentration of Cefuroxime. Management: Administer cefuroxime axetil at least 1 hour before or 2 hours after the administration of short-acting antacids. Taking cefuroxime with food may lessen the magnitude of this interaction. Risk D: Consider Therapy Modification
Chloroquine: Antacids may decrease serum concentration of Chloroquine. Management: Separate the 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 bioavailability of Corticosteroids (Oral). Management: Consider separating doses by 2 or more hours. Budesonide enteric coated tablets could dissolve prematurely if given with drugs that lower gastric acid, with unknown impact on budesonide therapeutic effects. Risk D: Consider Therapy Modification
Cysteamine (Systemic): Antacids may decrease therapeutic effects of Cysteamine (Systemic). Risk C: Monitor
Dabigatran Etexilate: Antacids may decrease 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
Dasatinib: Antacids may decrease serum concentration of Dasatinib. Management: Simultaneous administration of dasatinib and antacids should be avoided. If combined, administer antacids 2 hours before or 2 hours after dasatinib. Risk D: Consider Therapy Modification
Deferiprone: Polyvalent Cation Containing Products may decrease serum concentration of Deferiprone. Management: Separate administration of deferiprone and oral medications or supplements that contain polyvalent cations by at least 4 hours. Risk D: Consider Therapy Modification
Diacerein: Antacids may decrease absorption of Diacerein. Risk C: Monitor
Dolutegravir: Magnesium Salts may decrease serum concentration of Dolutegravir. Management: Administer dolutegravir at least 2 hours before or 6 hours after oral magnesium salts. Administer the dolutegravir/rilpivirine combination product at least 4 hours before or 6 hours after oral magnesium salts. Risk D: Consider Therapy Modification
Doxercalciferol: May increase hypermagnesemic effects of Magnesium Salts. Management: Consider using a non-magnesium-containing antacid or phosphate-binding product in patients also receiving doxercalciferol. If magnesium-containing products must be used with doxercalciferol, serum magnesium concentrations should be monitored closely. Risk D: Consider Therapy Modification
Eltrombopag: Polyvalent Cation Containing Products may decrease serum concentration of Eltrombopag. Management: Administer eltrombopag at least 2 hours before or 4 hours after oral administration of any polyvalent cation containing product. Risk D: Consider Therapy Modification
Elvitegravir: Polyvalent Cation Containing Products may decrease serum concentration of Elvitegravir. Management: Administer elvitegravir-containing products 2 hours before, or 2 to 6 hours after, the administration of polyvalent cation containing products. Risk D: Consider Therapy Modification
Erdafitinib: Serum Phosphate Level-Altering Agents may decrease therapeutic effects of Erdafitinib. Management: Avoid coadministration of serum phosphate level-altering agents with erdafitinib before initial dose increase period based on serum phosphate levels (Days 14 to 21). Risk D: Consider Therapy Modification
Erlotinib: Antacids may decrease serum concentration of Erlotinib. Management: Separate the administration of erlotinib and any antacid by several hours in order to minimize the risk of a significant interaction. Risk D: Consider Therapy Modification
Fexofenadine: Antacids may decrease serum concentration of Fexofenadine. Management: Separate the administration of fexofenadine and aluminum- or magnesium-containing antacids. Risk D: Consider Therapy Modification
Fosinopril: Antacids may decrease serum concentration of Fosinopril. Management: Separate administration of antacids and fosinopril by 2 hours. Risk D: Consider Therapy Modification
Gabapentin: Magnesium Salts may increase CNS depressant effects of Gabapentin. Specifically, high dose intravenous/epidural magnesium sulfate may enhance the CNS depressant effects of gabapentin. Magnesium Salts may decrease serum concentration of Gabapentin. Management: Administer gabapentin at least 2 hours after use of a magnesium-containing antacid. Monitor patients closely for evidence of reduced response to gabapentin therapy. Monitor for CNS depression if high dose IV/epidural magnesium sulfate is used. Risk D: Consider Therapy Modification
Gefitinib: Antacids may decrease serum concentration of Gefitinib. Management: Administer gefitinib at least 6 hours before or 6 hours after administration of an antacid, and closely monitor clinical response to gefitinib. Risk D: Consider Therapy Modification
Hyoscyamine: Antacids may decrease serum concentration of Hyoscyamine. Management: Administer immediate release and sublingual oral hyoscyamine before meals, and antacids after meals, when these agents are given in combination. Risk D: Consider Therapy Modification
Iron Preparations: Antacids may decrease absorption of Iron Preparations. Management: No action is likely necessary for the majority of patients who only use antacids intermittently or occasionally. Consider separating doses of oral iron and antacids in patients who require chronic use of both agents and monitor for reduced iron efficacy. Risk D: Consider Therapy Modification
Isoniazid: Antacids may decrease absorption of Isoniazid. Risk C: Monitor
Itraconazole: Antacids may decrease serum concentration of Itraconazole. Antacids may increase serum concentration of Itraconazole. Management: Administer Sporanox brand itraconazole at least 2 hours before or 2 hours after administration of any antacids. Exposure to Tolsura brand itraconazole may be increased by antacids; consider itraconazole dose reduction. Risk D: Consider Therapy Modification
Ketoconazole (Systemic): Antacids may decrease serum concentration of Ketoconazole (Systemic). Management: Administer antacids at least 1 hour prior to, or 2 hours after, ketoconazole. Additionally, administer ketoconazole with an acidic beverage (eg, non-diet cola) and monitor patients closely for signs of inadequate clinical response to ketoconazole. Risk D: Consider Therapy Modification
Lanthanum: Antacids may decrease therapeutic effects of Lanthanum. Management: Administer antacid products at least 2 hours before or after lanthanum. Risk D: Consider Therapy Modification
Ledipasvir: Antacids may decrease serum concentration of Ledipasvir. Management: Separate the administration of ledipasvir and antacids by 4 hours. Risk D: Consider Therapy Modification
Levoketoconazole: Antacids may decrease absorption of Levoketoconazole. Management: Advise patients to take antacids at least 2 hours after taking levoketoconazole. Risk D: Consider Therapy Modification
Levonadifloxacin: Antacids may decrease serum concentration of Levonadifloxacin. Risk X: Avoid
Levonadifloxacin: Magnesium Salts may decrease serum concentration of Levonadifloxacin. Risk X: Avoid
Levothyroxine: Magnesium Salts may decrease serum concentration of Levothyroxine. Management: Separate administration of oral levothyroxine and oral magnesium salts by at least 4 hours. Risk D: Consider Therapy Modification
Mesalamine: Antacids may decrease therapeutic effects of Mesalamine. Antacid-mediated increases in gastrointestinal pH may cause the premature release of mesalamine from specific sustained-release mesalamine products. Management: Avoid concurrent administration of antacids with the Apriso brand of mesalamine extended-release capsules. The optimal duration of dose separation is unknown. Other mesalamine products do not contain this interaction warning. Risk D: Consider Therapy Modification
Methenamine: Antacids may decrease therapeutic effects of Methenamine. Management: Consider avoiding the concomitant use of medications that alkalinize the urine, such as antacids, and methenamine. Monitor for decreased therapeutic effects of methenamine if used concomitant with antacids. Risk D: Consider Therapy Modification
MiSOPROStol: Antacids may increase adverse/toxic effects 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 X: Avoid
Multivitamins/Fluoride (with ADE): Magnesium Salts may decrease serum concentration of Multivitamins/Fluoride (with ADE). Specifically, magnesium salts may decrease fluoride absorption. Management: To avoid this potential interaction separate the administration of magnesium salts from administration of a fluoride-containing product by at least 1 hour. Risk D: Consider Therapy Modification
Multivitamins/Minerals (with ADEK, Folate, Iron): Antacids may decrease 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 multivitamins and antacids by as much time as possible to minimize impact of this interaction. Monitor for decreased therapeutic efficacy of oral iron preparations during coadministration. Risk D: Consider Therapy Modification
Neratinib: Antacids may decrease serum concentration of Neratinib. Specifically, antacids may reduce neratinib absorption. Management: Separate the administration of neratinib and antacids by giving neratinib at least 3 hours after the antacid. Risk D: Consider Therapy Modification
Neuromuscular-Blocking Agents: Magnesium Salts may increase neuromuscular-blocking effects of Neuromuscular-Blocking Agents. Risk C: Monitor
Nilotinib: Antacids may decrease serum concentration of Nilotinib. Management: Separate the administration of nilotinib and any antacid by at least 2 hours whenever possible in order to minimize the risk of a significant interaction. Risk D: Consider Therapy Modification
Nirogacestat: Antacids may decrease serum concentration of Nirogacestat. Management: If acid-reducing therapy is required, separate nirogacestat administration from antacids by 2 hours. Risk D: Consider Therapy Modification
Octreotide: Antacids may decrease serum concentration of Octreotide. Risk C: Monitor
PAZOPanib: Antacids may decrease serum concentration of PAZOPanib. Management: Avoid the use of antacids in combination with pazopanib whenever possible. Separate doses by several hours if antacid treatment is considered necessary. The impact of dose separation has not been investigated. Risk D: Consider Therapy Modification
PenicillAMINE: Polyvalent Cation Containing Products may decrease serum concentration of PenicillAMINE. Management: Separate the administration of penicillamine and oral polyvalent cation containing products by at least 1 hour. Risk D: Consider Therapy Modification
Pexidartinib: Antacids may decrease serum concentration of Pexidartinib. Management: Administer pexidartinib at least 2 hours before or 2 hours after antacids. Risk D: Consider Therapy Modification
Phosphate Supplements: Antacids may decrease absorption of Phosphate Supplements. Management: This applies only to oral phosphate administration. Separating administration of oral phosphate supplements from antacid administration by as long as possible may minimize the interaction. Risk D: Consider Therapy Modification
Phosphate Supplements: Magnesium Salts may decrease serum concentration of Phosphate Supplements. Management: Administer oral phosphate supplements as far apart from the administration of an oral magnesium salt as possible to minimize the significance of this interaction. Risk D: Consider Therapy Modification
Potassium Phosphate: Antacids may decrease serum concentration of Potassium Phosphate. Management: Consider separating administration of antacids and oral potassium phosphate by at least 2 hours to decrease risk of a significant interaction. Risk D: Consider Therapy Modification
QuiNINE: Antacids may decrease serum concentration of QuiNINE. Risk X: Avoid
Quinolones: Antacids may decrease absorption of Quinolones. Of concern only with oral administration of quinolones. Management: Avoid concurrent administration of quinolones and antacids to minimize the impact of this interaction. Recommendations for optimal dose separation vary by specific quinolone; see full monograph for details. Risk D: Consider Therapy Modification
Quinolones: Magnesium Salts may decrease serum concentration of Quinolones. Management: Administer oral quinolones several hours before (4 h for moxi/pe/spar/enox-, 2 h for others) or after (8 h for moxi-, 6 h for cipro/dela-, 4 h for lome/pe/enox-, 3 h for gemi-, and 2 h for levo-, nor-, or ofloxacin or nalidixic acid) oral magnesium salts. Risk D: Consider Therapy Modification
Raltegravir: Magnesium Salts may decrease serum concentration of Raltegravir. Management: Avoid the use of oral / enteral magnesium salts with raltegravir. No dose separation schedule has been established that adequately reduces the magnitude of interaction. Risk X: Avoid
Rilpivirine: Antacids may decrease serum concentration of Rilpivirine. Management: Administer antacids at least 2 hours before or 4 hours after oral rilpivirine when used with most rilpivirine products. However, administer antacids at least 6 hours before or 4 hours after the rilpivirine/dolutegravir combination product. Risk D: Consider Therapy Modification
Riociguat: Antacids may decrease serum concentration of Riociguat. Management: Separate the administration of antacids and riociguat by at least 1 hour in order to minimize any potential interaction. Monitor clinical response to riociguat more closely in patients using this combination. Risk D: Consider Therapy Modification
Rosuvastatin: Antacids may decrease serum concentration of Rosuvastatin. Risk C: Monitor
Roxadustat: Polyvalent Cation Containing Products may decrease serum concentration of Roxadustat. Management: Administer roxadustat at least 1 hour after the administration of oral polyvalent cation containing products. Risk D: Consider Therapy Modification
Selpercatinib: Antacids may decrease serum concentration of Selpercatinib. Management: Coadministration of selpercatinib and antacids should be avoided. If coadministration cannot be avoided, selpercatinib should be administered 2 hours before or 2 hours after antacids. Risk D: Consider Therapy Modification
Sodium Polystyrene Sulfonate: Laxatives (Magnesium Containing) may increase adverse/toxic effects 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. Risk X: Avoid
Sotalol: Antacids may decrease serum concentration of Sotalol. Management: Avoid simultaneous administration of sotalol and antacids. Administer antacids 2 hours after sotalol. Risk D: Consider Therapy Modification
Sotorasib: Antacids may decrease serum concentration of Sotorasib. Management: Avoid use with PPIs, PCABs, or H2RAs. If use of a gastric acid suppressing medication is needed, use antacids and administer sotorasib 4 hours before or 10 hours after oral antacid administration. Risk D: Consider Therapy Modification
Sparsentan: Antacids may decrease serum concentration of Sparsentan. Management: Administer sparsentan 2 hours before or 2 hours after antacids. Risk D: Consider Therapy Modification
Sucralfate: Antacids may decrease therapeutic effects of Sucralfate. Management: Consider separating the administration of antacids and sucralfate by at least 30 minutes. Risk D: Consider Therapy Modification
Sulpiride: Antacids may decrease serum concentration of Sulpiride. Management: Separate administration of antacids and sulpiride by at least 2 hours in order to minimize the impact of antacids on sulpiride absorption. Risk D: Consider Therapy Modification
Tetracyclines: Antacids may decrease absorption of Tetracyclines. Management: Separate administration of antacids and oral tetracycline derivatives by several hours when possible to minimize the extent of this potential interaction. Monitor for decreased therapeutic effects of tetracyclines. Risk D: Consider Therapy Modification
Tetracyclines: Magnesium Salts may decrease absorption of Tetracyclines. Only applicable to oral preparations of each agent. Management: Avoid coadministration of oral magnesium salts and oral tetracyclines. If coadministration cannot be avoided, administer oral magnesium at least 2 hours before, or 4 hours after, oral tetracyclines. Monitor for decreased tetracycline therapeutic effects. Risk D: Consider Therapy Modification
Thyroid Products: Antacids may decrease absorption of Thyroid Products. Risk C: Monitor
Trientine: Polyvalent Cation Containing Products may decrease serum concentration of Trientine. Management: Avoid concomitant use of trientine and polyvalent cations. If oral iron supplements are required, separate the administration by 2 hours. For other oral polyvalent cations, give trientine 1 hour before, or 1 to 2 hours after the polyvalent cation. Risk D: Consider Therapy Modification
Unithiol: May decrease therapeutic effects of Polyvalent Cation Containing Products. Risk X: Avoid
Velpatasvir: Antacids may decrease serum concentration of Velpatasvir. Management: Separate administration of velpatasvir and antacids by at least 4 hours. Risk D: Consider Therapy Modification
Should be taken with food and at least 8 oz of water. Whole grains, legumes, and dark-green leafy vegetables are dietary sources of magnesium.
Dietary reference intake (elemental magnesium) (IOM 1997):
1 to 6 months: Adequate intake: 30 mg/day.
7 to 12 months: Adequate intake: 75 mg/day.
1 to 3 years: Recommended dietary allowance (RDA): 80 mg/day.
4 to 8 years: RDA: 130 mg/day.
9 to 13 years: RDA: 240 mg/day.
14 to 18 years: RDA:
Females: 360 mg/day.
Pregnancy: 400 mg/day.
Lactation: 360 mg/day.
Males: 410 mg/day.
19 to 30 years: RDA:
Females: 310 mg/day.
Pregnancy: 350 mg/day.
Lactation: 310 mg/day.
Males: 400 mg/day.
≥31 years: RDA:
Females: 320 mg/day.
Pregnancy: 360 mg/day.
Lactation: 320 mg/day.
Males: 420 mg/day.
Magnesium crosses the placenta; serum concentrations in the fetus are similar to those in the mother (Idama 1998; Osada 2002)
Note: Ranges may slightly vary by individual laboratories.
Pediatric (Lo 2020):
≤6 days: 1.2 to 2.6 mg/dL (SI: 0.5 to 1.1 mmol/L or 1 to 2.1 mEq/L).
7 days to 2 years: 1.6 to 2.6 mg/dL (SI: 0.7 to 1.1 mmol/L or 1.3 to 2.1 mEq/L).
>2 to 14 years: 1.5 to 2.3 mg/dL (SI: 0.6 to 0.9 mmol/L or 1.2 to 1.9 mEq/L).
Magnesium is important as a cofactor in many enzymatic reactions in the body involving protein synthesis and carbohydrate metabolism (at least 300 enzymatic reactions require magnesium). Actions on lipoprotein lipase have been found to be important in reducing serum cholesterol and on sodium/potassium ATPase in promoting polarization (eg, neuromuscular functioning).
Absorption: Oral: Up to 30%
Excretion: Urine (IOM 1997); feces (as unabsorbed drug)
