Description:

Magnesium Sulfate 50% w/v Solution for Injection (BP) is a concentrated sterile solution of magnesium sulfate heptahydrate used primarily as an anticonvulsant to prevent and control seizures in severe pre-eclampsia and eclampsia (toxemia of pregnancy). It is also used to treat hypomagnesemia (low blood magnesium levels), especially in acute cases with signs of tetany (muscle spasms), and as a tocolytic (to delay preterm labor) in some protocols. The 50% w/v concentration provides 500 mg/ml (approximately 2 mmol/ml Mg²⁺).

Prescription:

Prescription-only.

Therapeutic Category:

Anticonvulsant / Electrolyte Replacement / Tocolytic (Magnesium salt for hypomagnesemia, eclampsia/pre-eclampsia seizure control, and preterm labor suppression.

Active Ingredients/Composition:

• Active ingredient: Magnesium sulfate heptahydrate BP – 500 mg per ml (50% w/v).
  • Provides approximately 2 mmol/ml (4 mEq/ml) of magnesium ions (Mg²⁺) and sulfate ions. Other ingredients: Water for injection (solvent); may contain hydrochloric acid or sodium hydroxide for pH adjustment (pH typically 4.5–7.0). The solution is clear, colorless to pale yellow, sterile, and non-pyrogenic.

Vitamins: None.

Minerals: Yes – Magnesium (from magnesium sulfate heptahydrate; therapeutic electrolyte replacement, not a dietary mineral supplement).

Variant:

• Magnesium Sulfate 50% w/v Solution for Injection (standard 50% concentration; common sizes 2 ml [1 g], 5 ml [2.5 g], or 10 ml [5 g] ampoules). Related variants: 20% or 10% diluted solutions (for safer IV infusion), larger infusion bags (e.g., 20% in 500 ml for controlled infusion), or other brands. The 50% w/v is the concentrated form requiring dilution for most IV uses.

Consume Type:

Injectable – Intravenous (IV) infusion (preferred for eclampsia and most indications) or Intramuscular (IM) injection (deep IM, alternate sites; less common now due to pain and slower absorption). Administered only by healthcare professionals.

Directions/Usage: Administered only in clinical settings (hospital or clinic) under close monitoring.

• Eclampsia/pre-eclampsia (seizure control): Loading dose 4–6 g IV over 15–20 minutes, followed by maintenance 1–2 g/hour continuous IV infusion (titrated to clinical response and serum magnesium levels).
• Hypomagnesemia: 1–2 g IV over 1–2 hours (or higher in severe cases), repeated as needed.
• Tocolysis (preterm labor, off-label in some protocols): Loading 4–6 g IV, then 1–3 g/hour maintenance.
• IM (alternative): 10 g (20 ml of 50%) deep IM (10 ml each buttock) initially, then 5 g IM every 4 hours.
• Always dilute 50% solution for IV use (to ≤20% concentration) and infuse slowly (rate not exceeding 1.5 ml/min of 10% solution).
• Monitor deep tendon reflexes, respiratory rate, urine output, serum magnesium, and vital signs (therapeutic range 4–8 mg/dL; toxicity >10 mg/dL).
• Antidote for toxicity: Calcium gluconate 1 g IV.

Common Side Effects: Common:

• Flushing, sweating, feeling warm.
• Hypotension (low blood pressure).
• Nausea, vomiting.
• Muscle weakness or lethargy.
• Bradycardia (slow heart rate). Rare/serious (seek immediate help): Respiratory depression (slow/shallow breathing – hallmark of toxicity), cardiac arrest, complete heart block, pulmonary edema, or hypermagnesemia symptoms (loss of deep tendon reflexes, drowsiness, confusion).

Package Type:

Glass ampoules of 2 ml, 5 ml, or 10 ml (each containing 50% w/v solution; packs of 5–10 ampoules; labelled carton with instructions and warnings). Some markets have plastic vials or larger bags for infusion.

Storage Advice: Store at room temperature (below 25–30°C) in original packaging, protected from light. Do not freeze. Keep out of reach of children.

Safety Advice:

• Administered only under medical supervision (high risk of toxicity – monitor reflexes, respiration, and serum magnesium closely).
• Contraindicated in myasthenia gravis (worsens muscle weakness), severe renal impairment (risk of accumulation), heart block, or hypersensitivity.
• Caution in renal impairment (dose reduction), respiratory disease, or elderly patients.
• Therapeutic monitoring essential (loss of patellar reflexes is early sign of toxicity).
• Calcium gluconate must be available as antidote.
• If respiratory rate <12/min, absent reflexes, or confusion occurs, stop infusion and give calcium gluconate 1 g IV.
• Keep out of reach of children (overdose risk).

Product Substitutes: Similar magnesium sulfate 50% w/v injections in Ghana include:

• Generic magnesium sulfate 50% w/v injection (various importers).
• Magnesium Sulfate Injection BP 50% (Martindale or other generics).
• Other brands like Magnesulf or local hospital generics. Alternatives: Magnesium sulfate in lower concentrations (e.g., 20% or 10% for safer infusion), or other tocolytics/anticonvulsants (e.g., nifedipine for preterm labor, phenytoin/levetiracetam for seizures). Consult doctor/pharmacist in Accra (e.g., Korle Bu Maternity) for alternatives.

Manufacturer/Marketer:

• Martindale

Country of Origin:

• UK