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 |