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Magnesium Hydroxide

Pronunciation

Pronunciation

(mag NEE zhum hye DROKS ide)

Index Terms

  • Magnesia Magma
  • Milk of Magnesia
  • MOM

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product

Suspension, Oral:

Dulcolax Milk of Magnesia: 400 mg/5 mL (355 mL) [sugar free; unflavored flavor]

Dulcolax Milk of Magnesia: 400 mg/5 mL (355 mL) [sugar free; contains saccharin sodium; mint flavor]

Milk of Magnesia: 400 mg/5 mL (355 mL, 480 mL); 1200 mg/15 mL (355 mL)

Milk of Magnesia: 1200 mg/15 mL (355 mL) [mint flavor]

Milk of Magnesia: 7.75% (360 mL, 480 mL)

Milk of Magnesia: 7.75% (355 mL, 473 mL) [mint flavor]

Milk of Magnesia: 7.75% (30 mL) [spearmint flavor]

Milk of Magnesia: 400 mg/5mL (473 mL [DSC])

Milk of Magnesia: 1200 mg/15 mL (355 mL) [gluten free, stimulant free, sugar free; contains saccharin sodium]

Milk of Magnesia: 400 mg/5 mL (355 mL, 473 mL) [low sodium, sugar free]

Milk of Magnesia: 400 mg/5 mL (473 mL, 769 mL); 1200 mg/15 mL (355 mL) [stimulant free, sugar free]

Milk of Magnesia: 1200 mg/15 mL (355 mL) [stimulant free, sugar free; contains saccharin sodium]

Milk of Magnesia: 400 mg/5 mL (473 mL); 1200 mg/15 mL (355 mL) [sugar free]

Milk of Magnesia Concentrate: 2400 mg/10 mL (100 mL, 400 mL) [lemon flavor]

Milk of Magnesia Concentrate: 2400 mg/10 mL (10 mL) [contains methylparaben, propylene glycol, propylparaben, saccharin sodium; lemon flavor]

Tablet Chewable, Oral:

Pedia-Lax: 400 mg [scored; stimulant free; contains fd&c red #40 aluminum lake; watermelon flavor]

Phillips: 311 mg [mint flavor]

Brand Names: U.S.

  • Dulcolax Milk of Magnesia [OTC]
  • Milk of Magnesia Concentrate [OTC]
  • Milk of Magnesia [OTC]
  • Pedia-Lax [OTC]
  • Phillips [OTC]

Pharmacologic Category

  • Antacid
  • Laxative
  • Magnesium Salt

Pharmacology

Promotes bowel evacuation by causing osmotic retention of fluid which distends the colon with increased peristaltic activity; reacts with hydrochloric acid in stomach to form magnesium chloride

Absorption

Oral: Up to 30%

Excretion

Urine (up to 30% as absorbed magnesium ions); feces (as unabsorbed drug)

Onset of Action

Laxative: 30 minutes to 6 hours

Use: Labeled Indications

Short-term treatment of occasional constipation and symptoms of hyperacidity

Contraindications

Hypersensitivity to magnesium hydroxide or any component of the formulation

Dosing: Adult

Antacid: OTC labeling: Oral:

Liquid: Magnesium hydroxide 400 mg/5 mL: 5-15 mL as needed up to 4 times/day

Tablet: Magnesium hydroxide 311 mg/tablet: 2-4 tablets every 4 hours up to 4 times/day

Laxative: OTC labeling: Oral:

Liquid:

Magnesium hydroxide 400 mg/5 mL: 30-60 mL/day once daily at bedtime or in divided doses

Magnesium hydroxide 800 mg/5 mL: 15-30 mL/day once daily at bedtime or in divided doses

Tablet: Magnesium hydroxide 311 mg/tablet: 8 tablets/day once daily at bedtime or in divided doses

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Antacid: OTC labeling: Oral:

Liquid: Children ≥12 years: Refer to adult dosing.

Tablet:

Children <12 years: Use not recommended.

Children ≥12 years: Refer to adult dosing.

Laxative: Oral:

Liquid: Magnesium hydroxide 400 mg/5 mL: 1-3 mL/kg/day; adjust dose to induce daily bowel movement

OTC labeling:

Children <2 years: Use not recommended.

Children 2-5 years: Magnesium hydroxide 400 mg/5 mL: 5-15 mL/day once daily at bedtime or in divided doses

Children 6-11 years:

Magnesium hydroxide 400 mg/5 mL: 15-30 mL/day once daily at bedtime or in divided doses

Magnesium hydroxide 800 mg/5 mL: 7.5-15 mL/day once daily at bedtime or in divided doses

Children ≥12 years: Refer to adult dosing.

Tablet: OTC labeling:

Children <3 years: Use not recommended.

Children 3-5 years: Magnesium hydroxide 311 mg/tablet: 2 tablets/day once daily at bedtime or in divided doses

Children 6-11 years: Magnesium hydroxide 311 mg/tablet: 4 tablets/day once daily at bedtime or in divided doses

Children ≥12 years: Refer to adult dosing.

Dosing: Renal Impairment

Patients in severe renal failure should not receive magnesium due to toxicity from accumulation. Patients with a CrCl <30 mL/minute should be monitored by serum magnesium levels.

Administration

Liquid doses may be diluted with a small amount of water prior to administration. All doses should be followed by 8 ounces of water.

Dietary Considerations

Some products may contain sodium.

Drug Interactions

Alfacalcidol: May increase the serum concentration of Magnesium Salts. Consider therapy modification

Allopurinol: Antacids may decrease the absorption of Allopurinol. Consider therapy modification

Alpha-Lipoic Acid: Magnesium Salts may decrease the absorption of Alpha-Lipoic Acid. Alpha-Lipoic Acid may decrease the absorption of Magnesium Salts. Consider therapy modification

Amphetamines: Antacids may decrease the excretion of Amphetamines. Monitor therapy

Antipsychotic Agents (Phenothiazines): Antacids may decrease the absorption of Antipsychotic Agents (Phenothiazines). Monitor therapy

Atazanavir: Antacids may decrease the absorption of Atazanavir. 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. Consider therapy modification

Bismuth Subcitrate: Antacids may diminish the therapeutic effect of Bismuth Subcitrate. Management: Avoid administration of antacids within 30 minutes of bismuth subcitrate (tripotassium bismuth dicitrate) administration. 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. Consider therapy modification

Bisphosphonate Derivatives: Magnesium Salts may decrease the serum concentration of Bisphosphonate Derivatives. Management: Avoid administration of oral magnesium salts within: 2 hours before or after tiludronate/clodronate/etidronate; 60 minutes after oral ibandronate; or 30 minutes after alendronate/risedronate. Exceptions: Pamidronate; Zoledronic Acid. Consider therapy modification

Bosutinib: Antacids may decrease the serum concentration of Bosutinib. Management: Administer antacids more than 2 hours before or after bosutinib. Consider therapy modification

Calcitriol (Systemic): May increase the 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. Consider therapy modification

Calcium Channel Blockers: May enhance the adverse/toxic effect of Magnesium Salts. Magnesium Salts may enhance the hypotensive effect of Calcium Channel Blockers. Monitor therapy

Calcium Polystyrene Sulfonate: Laxatives (Magnesium Containing) 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. Avoid combination

Captopril: Antacids may decrease the serum concentration of Captopril. Monitor therapy

Cefditoren: Antacids may decrease the serum concentration of Cefditoren. Management: Concomitant use of cefditoren with antacids is not recommended. Consider alternative methods to control acid reflux (eg, diet modification) or alternative antimicrobial therapy. If antacid therapy can not be avoided, separate dosing by several hours. Consider therapy modification

Cefpodoxime: Antacids may decrease the serum concentration of Cefpodoxime. Monitor therapy

Cefuroxime: Antacids may decrease the serum concentration of Cefuroxime. Management: Consider administering antacids and cefuroxime at least 2 hours apart. 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. Consider therapy modification

Corticosteroids (Oral): Antacids may decrease the 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. Consider therapy modification

Cysteamine (Systemic): Antacids may diminish the therapeutic effect of Cysteamine (Systemic). Monitor therapy

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. Consider therapy modification

Dabrafenib: Antacids may decrease the serum concentration of Dabrafenib. Monitor therapy

Dasatinib: Antacids may decrease the absorption of Dasatinib. Consider therapy modification

Deferiprone: Antacids may decrease the serum concentration of Deferiprone. Management: Separate administration of deferiprone and oral medications or supplements that contain polyvalent cations by at least 4 hours. Consider therapy modification

Deferiprone: Magnesium Salts may decrease the serum concentration of Deferiprone. Management: Separate administration of deferiprone and oral medications or supplements that contain polyvalent cations by at least 4 hours. Consider therapy modification

Delavirdine: Antacids may decrease the serum concentration of Delavirdine. Management: Separate doses of delavirdine and antacids by at least 1 hour. Monitor for decreased delavirdine therapeutic effects with this combination. Consider therapy modification

Dexmethylphenidate: Antacids may increase the absorption of Dexmethylphenidate. Specifically, antacids may interfere with the normal release of drug from the extended-release capsules (Focalin XR brand), which could result in both increased absorption (early) and decreased delayed absorption. Monitor therapy

Diacerein: Antacids may decrease the absorption of Diacerein. Monitor therapy

Dolutegravir: Magnesium Salts may decrease the serum concentration of Dolutegravir. Management: Administer dolutegravir at least 2 hours before or 6 hours after oral magnesium salts. Consider therapy modification

Doxercalciferol: May enhance the hypermagnesemic effect 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. Consider therapy modification

Eltrombopag: Magnesium Salts may decrease the serum concentration of Eltrombopag. Management: Administer eltrombopag at least 2 hours before or 4 hours after oral administration of any magnesium-containing product. Consider therapy modification

Elvitegravir: Antacids may decrease the serum concentration of Elvitegravir. Management: Separate administration of antacids and elvitegravir-containing products by at least 2 hours in order to minimize the risk for an interaction. Consider therapy modification

Erlotinib: Antacids may decrease the 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. 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. Consider therapy modification

Fosinopril: Antacids may decrease the serum concentration of Fosinopril. Management: The US and Canadian fosinopril manufacturer labels recommend separating the doses of antacids and fosinopril by 2 hours. 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. Consider therapy modification

Gabapentin: Magnesium Salts may enhance the CNS depressant effect of Gabapentin. Specifically, high dose intravenous/epidural magnesium sulfate may enhance the CNS depressant effects of gabapentin. Magnesium Salts may decrease the serum concentration of Gabapentin. Management: Administer gabapentin at least 2 hours after oral magnesium salts administration. Monitor patients closely for evidence of reduced response to gabapentin therapy. Monitor for CNS depression if high dose IV/epidural magnesium sulfate is used. Consider therapy modification

Gefitinib: Antacids may decrease the serum concentration of Gefitinib. Management: Administer gefitinib at least 6 hours before or after administration of an antacid, and closely monitor clinical response to gefitinib. Consider therapy modification

HMG-CoA Reductase Inhibitors: Antacids may decrease the serum concentration of HMG-CoA Reductase Inhibitors. Monitor therapy

Hyoscyamine: Antacids may decrease the serum concentration of Hyoscyamine. Management: Administer immediate release hyoscyamine before meals and antacids after meals when these agents are given in combination. Consider therapy modification

Iron Salts: Antacids may decrease the absorption of Iron Salts. Exceptions: Ferric Carboxymaltose; Ferric Citrate; Ferric Gluconate; Ferric Hydroxide Polymaltose Complex; Ferric Pyrophosphate Citrate; Ferumoxytol; Iron Dextran Complex; Iron Sucrose. Consider therapy modification

Isoniazid: Antacids may decrease the absorption of Isoniazid. 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. 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. Consider therapy modification

Ledipasvir: Antacids may decrease the serum concentration of Ledipasvir. Management: Separate the administration of ledipasvir and antacids by 4 hours. Consider therapy modification

Levothyroxine: Magnesium Salts may decrease the serum concentration of Levothyroxine. Management: Separate administration of oral levothyroxine and oral magnesium salts by at least 4 hours. Consider therapy modification

Mesalamine: Antacids may diminish the therapeutic effect 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 sustained-release mesalamine products. Separating antacid and mesalamine administration, and/or using lower antacid doses may be adequate means of avoiding this interaction. Consider therapy modification

Methenamine: Antacids may diminish the therapeutic effect of Methenamine. Consider therapy modification

Methylphenidate: Antacids may increase the absorption of Methylphenidate. Specifically, antacids may interfere with the normal release of drug from the extended-release capsules (Ritalin LA brand), which could result in both increased absorption (early) and decreased delayed absorption. Monitor therapy

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). Avoid combination

Multivitamins/Fluoride (with ADE): Magnesium Salts may decrease the 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. 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. 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. Consider therapy modification

Mycophenolate: Magnesium Salts may decrease the serum concentration of Mycophenolate. Management: Separate doses of mycophenolate and oral magnesium salts. Monitor for reduced effects of mycophenolate if taken concomitant with oral magnesium salts. Consider therapy modification

Neuromuscular-Blocking Agents: Magnesium Salts may enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Monitor therapy

Nilotinib: Antacids may decrease the 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. Consider therapy modification

PAZOPanib: Antacids may decrease the 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. Consider therapy modification

PenicillAMINE: Antacids may decrease the serum concentration of PenicillAMINE. Consider therapy modification

Phosphate Supplements: Antacids may decrease the absorption of Phosphate Supplements. Management: This applies only to oral phosphate administration. Separating administer of oral phosphate supplements from antacid administration by as long as possible may minimize the interaction. Exceptions: Sodium Glycerophosphate Pentahydrate. Consider therapy modification

Phosphate Supplements: Magnesium Salts may decrease the serum concentration of Phosphate Supplements. Management: This applies only to oral phosphate and magnesium administration. Administer oral phosphate supplements at least 1 hour before, or 2 hours after, oral magnesium salt administration. Exceptions: Sodium Glycerophosphate Pentahydrate. Consider therapy modification

Potassium Acid Phosphate: Antacids may decrease the serum concentration of Potassium Acid Phosphate. Management: Consider separating administration of antacids and oral potassium phosphate by at least 2 hours to decrease risk of a significant interaction. Consider therapy modification

QuiNIDine: Antacids may decrease the excretion of QuiNIDine. Monitor therapy

QuiNINE: Antacids may decrease the serum concentration of QuiNINE. Avoid combination

Quinolone Antibiotics: Antacids may decrease the absorption of Quinolone Antibiotics. Of concern only with oral administration of quinolones. Exceptions: LevoFLOXacin (Oral Inhalation). Consider therapy modification

Quinolone Antibiotics: Magnesium Salts may decrease the serum concentration of Quinolone Antibiotics. Management: Administer oral quinolones at least several hours before (4 h for moxi- and sparfloxacin, 2 h for others) or after (8 h for moxi-, 6 h for cipro-, 4 h for lome-, 3 h for gemi-, and 2 h for levo-, nor-, or ofloxacin or nalidixic acid) oral magnesium salts. Exceptions: LevoFLOXacin (Oral Inhalation). Consider therapy modification

Raltegravir: Magnesium Salts may decrease the 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. Avoid combination

Rilpivirine: Antacids may decrease the serum concentration of Rilpivirine. Management: Administer antacids at least 2 hours before or 4 hours after rilpivirine. Consider therapy modification

Riociguat: Antacids may decrease the serum concentration of Riociguat. Management: Separate the administration of antacids and riociguat by at least 1 hour in order to minimize any potential interaction. Consider therapy modification

Sodium Polystyrene Sulfonate: Laxatives (Magnesium Containing) 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. Avoid combination

Sotalol: Antacids may decrease the serum concentration of Sotalol. Management: Avoid simultaneous administration of sotalol and antacids. Administer antacids 2 hours after sotalol. Consider therapy modification

Strontium Ranelate: Magnesium Hydroxide may decrease the serum concentration of Strontium Ranelate. Management: Separate administration of strontium ranelate and magnesium hydroxide by at least 2 hours whenever possible in order to minimize this interaction. Consider therapy modification

Sulpiride: Antacids may decrease the 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. Consider therapy modification

Tetracycline Derivatives: Antacids may decrease the absorption of Tetracycline Derivatives. Consider therapy modification

Tetracycline Derivatives: Magnesium Salts may decrease the absorption of Tetracycline Derivatives. Only applicable to oral preparations of each agent. Consider therapy modification

Trientine: Antacids may decrease the absorption of Trientine. Management: Separate trientine dosing from other oral drugs (eg, antacids) by at least 1 hour. Monitor for decreased therapeutic effects of trientine if an antacid is initiated/dose increased, or increased effects if an antacid is discontinued/dose decreased. Consider therapy modification

Trientine: May decrease the serum concentration of Magnesium Salts. Magnesium Salts may decrease the serum concentration of Trientine. Consider therapy modification

Velpatasvir: Antacids may decrease the serum concentration of Velpatasvir. Management: Separate administration of velpatasvir and antacids by at least 4 hours. Consider therapy modification

Test Interactions

Increased magnesium; decreased protein, calcium (S), decreased potassium (S)

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:

• OTC use: For occasional use only; serious side effects may occur with prolonged use. For use only under the supervision of a healthcare provider in patients with kidney dysfunction, or with a sudden change in bowel habits which persist for >2 weeks. Do not use if abdominal pain, nausea, or vomiting are present. Patients should notify healthcare provider of any sudden change in bowel habits which last >14 days, stomach pain, nausea, or vomiting or if use is needed for >1 week. Not for OTC use in children <2 years of age.

Pregnancy Considerations

Magnesium crosses the placenta; serum concentrations in the fetus are similar to those in the mother (Idama, 1998; Osada, 2002). The American Gastroenterological Association considers the use of magnesium containing antacids to be low risk in pregnancy (Mahadevan, 2006).

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Patient may experience bad taste. Have patient report immediately to prescriber severe nausea, severe vomiting, severe diarrhea, lack of appetite, or muscle weakness (HCAHPS).

• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for healthcare professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience and judgment in diagnosing, treating and advising patients.

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