II. Indications
III. Contraindications
- Renal Failure
- Infants (relative contraindication)
- Higher risk for Hypermagnesemia
IV. Mechanism
- Magnesium salt Osmotic Laxative
- Poorly absorbed, hyperosmolar agent
V. Precautions
- Avoid longterm use due to Electrolyte loss risk
- These agents are typically used once as part of a bowel regimen
VI. Medications
- See Aluminum Hydroxide and Magnesium Hydroxide Antacid
- Magnesium Hydroxide Laxative concentrations
- Regular strength: 400 mg/5 ml
- Extra-Strength: 800 mg/5 ml
- Very High Concentration: 1200 mg/5 ml
VII. Dosing: Constipation
- See Aluminum Hydroxide and Magnesium Hydroxide Antacid
-
General
- Onset 0.5 to 6 hours
- Recommended as a single bedtime dose
- Concentration: 400 mg/5 ml (regular strength)
- Adult (and age >12 years)
- Take 30 to 60 ml (2.4 to 4.8 g) orally divided once to twice for 1 day
- Child (age <12 years)
- Age <2 years: 0.5 ml/kg/day divided once to twice for 1 day (caution, risk of Hypermagnesemia)
- Age 2 to 5 years: 5 to 15 ml (0.4 to 1.2 g) divided once to twice for 1 day
- Age 6 to 12 years: 15 to 30 ml (1.2 to 2.4 g) divided once to twice for 1 day
- Adult (and age >12 years)
- Concentration 800 mg/5 ml (extra strength)
- Adult: 15 to 30 ml orally divided once to twice for 1 day
- Concentration 1200 mg/5 ml (very high concentration)
- Adult: 10 to 20 ml orally divided once to twice for 1 day
VIII. Pharmacokinetics
- Rapid onset within 3 hours
IX. Adverse Effects
- Abdominal cramping (higher doses)
- Hypermagnesemia (in patients with Renal Failure, infants)
X. Safety
- Pregnancy Category B
- Unknown Safety in Lactation
XI. Resources
- Magnesium Hydroxide (DailyMed)
XII. References
- (2023) Management of Constipation, Presc Lett, #390108
- Hamilton (2020) Tarascon Pocket Pharmacopoeia
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Related Studies
milk of magnesia (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
MILK OF MAGNESIA SUSPENSION | Generic OTC | $0.01 per ml |
Ontology: Magnesium Hydroxide (C0024476)
Definition (NCI) | A solution of magnesium hydroxide with antacid and laxative properties. Milk of magnesium exerts its antacid activity in low doses such that all hydroxide ions that enter the stomach are used to neutralize stomach acid. This agent exerts its laxative effect in higher doses so that hydroxide ions are able to move from the stomach to the intestines where they attract and retain water, thereby increasing intestinal movement (peristalsis) and inducing the urge to defecate. |
Definition (MSH) | An inorganic compound that occurs in nature as the mineral brucite. It acts as an antacid with cathartic effects. |
Concepts | Pharmacologic Substance (T121) , Inorganic Chemical (T197) |
MSH | D008276 |
SnomedCT | 387337001, 317584009, 25550008, 60468008 |
English | Magnesium Hydrate, Hydroxide, Magnesium, Magnesium Hydroxide, Hydrate, Magnesium, Magnesium hydroxide (Mg(OH)2), magnesium hydroxide, Magnesium hydroxide [laxative], Magnesium hydrate, antacids magnesium OH, magnesium hydroxide (medication), MAGNESIUM HYDROXIDE, Magnesium Hydroxide [Chemical/Ingredient], magnesium hydrate, hydroxide laxative magnesium, hydroxide magnesium, Magnesium hydroxide [laxative] (product), Magnesium hydrate (substance), Magnesium hydroxide, Magnesium hydroxide (product), Magnesium hydroxide (substance), Magnesium hydroxide [laxative] (substance) |
French | Hydroxyde de magnésium |
Swedish | Magnesiumhydroxid |
Czech | hydroxid hořečnatý |
Finnish | Magnesiumhydroksidi |
Russian | MAGNIIA GIDROOKIS', BRUSIT, BRUTSIT, MAGNIIA GIDROKSID, БРУСИТ, БРУЦИТ, МАГНИЯ ГИДРОКСИД, МАГНИЯ ГИДРООКИСЬ |
Japanese | 水酸化マグネシウム, ブルーサイト |
Italian | Idrato di magnesio, Idrossido di magnesio |
Polish | Wodorotlenek magnezowy |
Norwegian | Magnesiumhydrat, Magnesiumhydroksid |
Spanish | hidróxido de magnesio (laxante), hidrato de magnesio (sustancia), hidróxido de magnesio (laxante) (producto), hidrato de magnesio, hidróxido de magnesio (producto), hidróxido de magnesio (sustancia), hidróxido de magnesio, Hidróxido de Magnesio |
German | Magnesiumhydroxid |
Portuguese | Hidróxido de Magnésio |
Ontology: MILK OF MAGNESIA (C0591789)
Concepts | Pharmacologic Substance (T121) , Inorganic Chemical (T197) |
English | MILK OF MAGNESIA, Milk of Magnesia, MILK OF MAGNESIA [VA Product], magnesia milk, milk of magnesia |