Dosage Forms
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Solution, Oral:
Citroma: 1.745 g/30 mL (296 mL) [contains polyethylene glycol, saccharin sodium; lemon flavor]
Citroma: 1.745 g/30 mL (296 mL) [low sodium; contains alcohol, usp, benzoic acid, disodium edta]
Citroma: 1.745 g/30 mL (296 mL) [low sodium; contains fd&c red #40, saccharin sodium; cherry flavor]
Citroma: 1.745 g/30 mL (296 mL) [low sodium; contains saccharin sodium; lemon flavor]
GoodSense Magnesium Citrate: 1.745 g/30 mL (296 mL) [contains polyethylene glycol, saccharin sodium]
GoodSense Magnesium Citrate: 1.745 g/30 mL (296 mL) [low sodium; contains alcohol, usp, fd&c red #40, saccharin sodium]
GoodSense Magnesium Citrate: 1.745 g/30 mL (296 mL) [low sodium; contains saccharin sodium; lemon flavor]
GoodSense Magnesium Citrate: 1.745 g/30 mL (296 mL) [saccharin free; contains benzoic acid, disodium edta]
Generic: 1.745 g/30 mL (296 mL)
Tablet, Oral:
Generic: 100 mg
Pharmacology
Mechanism of Action
Promotes bowel evacuation by causing osmotic retention of fluid which distends the colon with increased peristaltic activity
Pharmacokinetics/Pharmacodynamics
Absorption
Oral: Up to 30%
Excretion
Urine (IOM 1997); feces (as unabsorbed drug)
Onset of Action
Laxative effect: Oral solution: 0.5 to 6 hours
Use: Labeled Indications
Occasional constipation: Treatment of occasional constipation
Use: Off Label
Bowel preparation before colonoscopycyes
Based on the the American Society for Gastrointestinal and Endoscopy (ASGE) guideline for bowel preparation before colonoscopy, routine use of magnesium citrate as a stand-alone colonoscopy preparation is not recommended for routine use due to limited efficacy data and potential toxicity. A randomized, prospective 2-part study supports use of magnesium citrate as an effective and well tolerated low-volume colonoscopy preparation Berkelhammer 2002.
Contraindications
OTC labeling: When used for self-medication, do not use if on low salt diet
Dosage and Administration
Dosing: Adult
Bowel preparation before colonoscopy (off-label use): Note: This preparation should be avoided in patients with renal impairment, heart failure, decompensated cirrhosis, or baseline electrolyte abnormalities (A-Rahim 2018). There is no standard dosing for administration; the following recommendations are suggested by some experts.
Single-dose, same-day (for afternoon procedures): Oral: 1.5 bottles (450 mL or 15 oz) taken 8 hours prior to procedure, followed by clear liquids (at least three 240 mL glasses) over 2 hours. Four hours prior to the procedure, administer a second 1.5 bottle dose followed by clear liquids (three 240 mL glasses) over 1 hour (A-Rahim 2018).
Split-dose (evening before procedure): Oral: 1 to 1.5 bottles (300 to 450 mL or 10 to 15 oz) in the early evening (ie, between 6 and 8 PM) followed by clear liquids (at least three 240 mL glasses) over 2 hours. Patient should also be given a clear liquid diet the day prior to the procedure. Six hours prior to the colonoscopy, administer a second 1 to 1.5 bottle dose followed by clear liquids (three 240 mL glasses) over 1 hour (ASGE [Saltzman 2015]; A-Rahim 2018).
Laxative: Oral: Solution: 195 to 300 mL given once or in divided doses
Dosing: Geriatric
Refer to adult dosing.
Bowel preparation before colonoscopy (off-label use): The ASGE does not recommend use in the elderly (ASGE [Saltzman 2015]); however, some experts suggest that older patients without comorbidities and who cannot tolerate a higher volume preparation may receive magnesium citrate (A-Rahim 2018).
Dosing: Pediatric
Constipation, occasional: Note: Use of magnesium citrate has generally been replaced with other laxatives (eg, PEG solutions, lactulose) less likely to cause adverse effects (eg, electrolyte disturbances) (Tabbers 2014): Oral solution: Oral:
Children 2 to <6 years: 60 to 90 mL administered as a single dose or in divided doses
Children 6 to <12 years: 100 to 150 mL administered as a single dose or in divided doses
Children ≥12 years and Adolescents: 150 to 300 mL administered as a single dose or in divided doses
Bowel preparation: Limited data available: Oral: Oral Solution: Children >6 years and Adolescents: 4 to 6 mL/kg/day, may administer as a single dose or in divided doses the day before the procedure; maximum daily dose: 300 mL/day (NASPGHAN [Pall 2014])
Administration
Oral: To increase palatability, chill the solution prior to administration. Administer each dose with 8 oz (240 mL) of water.
Dietary Considerations
Some products may contain potassium and/or sodium.
Storage
Store at 15°C to 30°C (59°F to 86°F).
Oral solution: Discard remaining medication within 24 hours of opening.
Drug Interactions
Alfacalcidol: May increase the serum concentration of Magnesium Salts. 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
Aluminum Hydroxide: Citric Acid Derivatives may increase the absorption of Aluminum Hydroxide. Monitor therapy
Baloxavir Marboxil: Polyvalent Cation Containing Products may decrease the serum concentration of Baloxavir Marboxil. Avoid combination
Bictegravir: Polyvalent Cation Containing Products may decrease the serum concentration of Bictegravir. Management: Administer bictegravir under fasting conditions 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. Consider therapy modification
Bisphosphonate Derivatives: Polyvalent Cation Containing Products may decrease the 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. Exceptions: Pamidronate; Zoledronic Acid. 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
Deferiprone: Polyvalent Cation Containing Products 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
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. Administer the dolutegravir/rilpivirine combination product at least 4 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: Polyvalent Cation Containing Products may decrease the serum concentration of Eltrombopag. Management: Administer eltrombopag at least 2 hours before or 4 hours after oral administration of any polyvalent cation containing product. 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 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. 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
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
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
PenicillAMINE: Polyvalent Cation Containing Products may decrease the serum concentration of PenicillAMINE. Management: Separate the administration of penicillamine and oral polyvalent cation containing products by at least 1 hour. Consider therapy modification
Phosphate Supplements: Magnesium Salts may decrease the 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. Exceptions: Sodium Glycerophosphate Pentahydrate. Consider therapy modification
Quinolones: Magnesium Salts may decrease the serum concentration of Quinolones. Management: Administer oral quinolones several hours before (4 h for moxi/pe/spar-, 2 h for others) or after (8 h for moxi-, 6 h for cipro/dela-, 4 h for lome/pe-, 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
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
Tetracyclines: Magnesium Salts may decrease the absorption of Tetracyclines. Only applicable to oral preparations of each agent. Exceptions: Eravacycline. Consider therapy modification
Trientine: Polyvalent Cation Containing Products may decrease the serum concentration of Trientine. Management: Avoid concomitant administration of trientine and oral products that contain polyvalent cations. If oral iron supplements are required, separate the administration by 2 hours. If other oral polyvalent cations are needed, separate administration by 1 hour. Consider therapy modification
Test Interactions
Increased magnesium; decreased protein, decreased calcium (S), decreased potassium (S)
Adverse Reactions
Frequency not defined: Gastrointestinal: Abdominal pain, diarrhea, flatulence, nausea, vomiting
Warnings/Precautions
Disease-related concerns:
- Constipation (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, sodium- or magnesium-restricted diets, abdominal pain/nausea/vomiting, with a sudden change in bowel habits which has persisted for >2 weeks, or use of a laxative for >1 week. If rectal bleeding develops or a bowel movement does not occur after use, discontinue use and consult a health care provider.
- 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.
Pregnancy
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 citrate as a laxative to be low risk in pregnancy, but long term use should be avoided (not the preferred treatment of chronic constipation) (Mahadevan 2006).
Patient Education
What is this drug used for?
- It is used to clean out the GI (gastrointestinal) tract.
- It is used to treat constipation.
Frequently reported side effects of this drug
- Abdominal pain
- Diarrhea
- Passing gas
Other side effects of this drug: Talk with your doctor right away if you have any of these signs of:
- Signs of a significant reaction like 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. Talk to your doctor if you have questions.
Consumer Information Use and Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using this medicine.
