Magnesium sulfate
MgSO₄
What it isMagnesium replacement with NMDA-antagonist and membrane-stabilizing effects; eclampsia and torsades.
Why this oneIt treats eclamptic seizures and torsades even when the measured magnesium level is normal.
What limits it⚑ Loss of deep tendon reflexes signals toxicity before respiratory depression; calcium gluconate reverses it. Renal clearance matters.
FDA-approved for
- preeclampsia/eclampsia
- torsades / hypomagnesemia
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Relief of occasional constipation (irregularity); generally produces bowel movement in 1/2 to 6 hours | Adults and children ≥12 yr | 10–30 g (2–6 level tsp) daily, as a single dose or in divided doses | 10–30 g daily | 30 g/day |
| Relief of occasional constipation (irregularity); generally produces bowel movement in 1/2 to 6 hours | Children 6 to <12 yr | 5–10 g (1–2 level tsp) daily, as a single dose or in divided doses | 5–10 g daily | 10 g/day |
Renal Undefined
Hepatic Undefined
Instructions
- Dissolve the dose in 8 ounces of water; lemon juice may be added to improve taste.
- Drink a full glass (8 ounces) of liquid with each dose.
- May be taken as a single daily dose or in divided doses.
- Do not exceed the recommended daily dosage.
- Children under 6 years: consult a doctor.
Available strengths
- granules 100 g/100 g
- granules 1 g/g
- sol 1 g/g
- sol 1000 mg/g
- crystal 1 g/g
- inj 10, 80, 500 mg/mL
Cautions
- Ask a doctor before use in kidney disease, a magnesium-restricted diet, abdominal pain/nausea/vomiting, a sudden change in bowel habits persisting over 2 weeks, or laxative use already longer than 1 week.
- Take 2 or more hours before or after other drugs - laxatives may affect how other drugs work (ask a doctor or pharmacist if taking any other drug).
- Stop use and ask a doctor if rectal bleeding or failure to have a bowel movement after use - these could be signs of a serious condition.
- In case of overdose, get medical help or contact a Poison Control Center right away.
Pregnancy If pregnant, ask a health professional before use (OTC Drug Facts).
Lactation If breast-feeding, ask a health professional before use (OTC Drug Facts).
Cost
| Strength | #/mo | generic $/unit | CostPlus | |
|---|---|---|---|---|
| 100 g/100 g | granules | per unit | not offered | |
| 1 g/g | granules | per unit | $0.00/g | not offered |
NO BOXED WARNINGS
Principal riskLoss of deep tendon reflexes is the first sign of toxicity
Classes and tags
Clinical profile
Defining liabilityHypermagnesemic respiratory paralysis and circulatory collapse