Clinical beta

FMBM is currently in clinical beta. Content is for professional review/testing and must not replace local protocols, senior clinical judgment, or official prescribing references.

Drug Monograph

Magnesium-Sulfate

Preparation Calculator

USE IF: Torsades de pointes, eclampsia, hypomagnesemia, severe asthma (adjunct)

AVOID IF: Severe renal failure without monitoring, hypermagnesemia

Magnesium Sulfate

Electrolyte therapy and antiarrhythmic adjunct

AdultPediatricERICUObstetricsHigh-yield

Indication

Torsades • Eclampsia • Hypomagnesemia • Severe asthma (adjunct)

At a glance

INDICATIONS (CORE USE)

- Torsades de pointes - Eclampsia / preeclampsia - Hypomagnesemia - Severe asthma (adjunct)

ADULT DOSE (STANDARD)

Indication-specific IV dosing (bolus or infusion) per protocol

MAX DOSE

Protocol- and toxicity-sign-limited; reassess continuously in high-dose use

Route

IV

PEDIATRIC DOSE

Protocol-based

Do not miss

Must-not-miss safety points

Major warning

- Respiratory depression can occur at high magnesium levels - Loss of deep tendon reflexes is an early toxicity sign - Rapid infusion can cause hypotension - Antidote for toxicity is IV calcium

Institutional protocol required

Dosing for this medication is not a substitute for your hospital order set, pharmacy verification, or specialty protocol. Use only with an approved institutional pathway, continuous monitoring, and independent double-check where policy requires.

FMBM beta: decision support only — not medical advice or a prescribing system.

Indications

INDICATION: Torsades • Eclampsia • Hypomagnesemia • Severe asthma (adjunct)

Primary

  • Torsades de pointes
  • Eclampsia

Secondary

  • Hypomagnesemia
  • Severe asthma (adjunct)

Institutional protocol required

Dosing for this medication is not a substitute for your hospital order set, pharmacy verification, or specialty protocol. Use only with an approved institutional pathway, continuous monitoring, and independent double-check where policy requires.

Numeric examples in this monograph are illustrative only when present — always follow your verified institutional protocol and product labeling.

FMBM beta: decision support only — not medical advice or a prescribing system.

Dosing

STANDARD (ADULT PO)

TORSADES: IV bolus ECLAMPSIA: loading dose plus maintenance infusion HYPO-MG: IV replacement dosing ASTHMA: IV adjunct in severe cases

ADULT DOSE

STANDARD (ADULT): TORSADES: - IV bolus ECLAMPSIA: - Loading dose + maintenance infusion HYPO-MG: - Replacement dosing (IV) ASTHMA: - IV adjunct in severe cases

PEDIATRIC DOSE

Protocol-based

MAX DOSE

No single fixed max across indications; toxicity signs and protocol endpoints govern continuation

Practical Note

- Dose depends on indication - Avoid rapid administration unless specifically indicated (e.g., torsades) - Use indication-specific monitoring thresholds

Warnings

Clinical warnings

  • Use only with an approved institutional order set and pharmacy verification — this monograph is clinical decision support, not standalone prescribing authority.
  • Respiratory depression
  • Hypotension
  • Bradycardia
  • Loss of reflexes (toxicity)

Adverse effects

  • Flushing
  • Nausea
  • Weakness

Contraindications

  • Hypermagnesemia
  • Severe renal failure without monitoring

Drug interactions

  • Other CNS depressants increase respiratory risk
  • Calcium channel blockers may produce additive hypotension

Special populations

Pediatrics

Protocol-based

Pregnancy

Pregnancy: First-line for eclampsia per protocol

Lactation

Use with routine maternal monitoring as clinically indicated.

Renal impairment

High accumulation risk in renal dysfunction; monitor closely and adjust per protocol.

Hepatic impairment

No primary hepatic dosing pathway; monitor total critical-care physiology and toxicity signs.

Elderly

Use cautious dosing and close respiratory/hemodynamic monitoring due to increased sensitivity.

Administration

- IV slow infusion (except emergency bolus for torsades) - Continuous monitoring in high-dose use

Monitoring

  • Monitor: - Respiratory status - Reflexes (critical) - Magnesium levels (if prolonged use) - Blood pressure
  • Recheck: - During infusion - After bolus
  • Hold / reassess: - Loss of reflexes - Respiratory depression - Hypotension

Overdose / toxicity

Clinical Picture

Loss of reflexes, respiratory depression, and cardiac conduction abnormalities

Immediate Actions

Stop magnesium and support airway/breathing

Antidote

IV calcium

Decontamination

Supportive toxicology-directed care

Escalation

Escalate for progressive respiratory compromise, severe hypotension, or conduction instability

Clinical pearls

Common mistakes, resistance logic, and bedside traps

High-Yield

  • First-line for torsades
  • First-line for eclampsia

Clinical

  • Deep tendon reflexes are an early and useful toxicity marker

Safety

  • Most dangerous error is missing early toxicity signs

Pharmacy Tool

Magnesium Sulfate Safety Panel

  • Magnesium sulfate is a HIGH-ALERT medication.
  • Verify indication before use: eclampsia/seizure prophylaxis, severe asthma adjunct, hypomagnesemia, or torsades protocol.
  • Verify route, concentration, dose units, infusion rate, and renal function before administration.
  • IV magnesium sulfate must be diluted and administered via controlled infusion per institutional protocol.
  • For eclampsia: use standardized loading dose and maintenance infusion protocols per institutional guidelines.
  • Ensure adequate urine output before repeat dosing; reduce or hold in oliguria.
  • Rapid IV administration may cause hypotension and cardiac instability; adhere to recommended infusion rates.
  • Monitor respiratory rate, blood pressure, deep tendon reflexes, urine output, and serum magnesium when clinically indicated.
  • Toxicity signs: loss of reflexes, respiratory depression, hypotension, bradycardia, and cardiac arrest.
  • Calcium gluconate should be immediately available as antidote for magnesium toxicity.
  • Use caution in renal impairment due to accumulation risk.
  • Double-check dose and route with another clinician/pharmacist when required by policy.

Pharmacokinetics

- Renal excretion - Accumulates in renal failure

Mechanism of action

- Stabilizes cardiac and neuromuscular activity

Common brand names

Saudi Arabia

Magnesium sulfate (IV)

Global

Magnesium sulfate, (placeholder — verify local formulation)

Common trade names are curated examples only — formulations and availability vary. Verify the exact product name with your local pharmacy and national regulator before prescribing or dispensing.

Country practice notes

Global data (no country-specific data available)

  • Follow local antimicrobial stewardship policy, hospital formulary, and national resistance guidance.
  • Confirm dosing, stock, and restrictions with institutional pharmacy and current product labeling.

References

Saudi Arabia

  • SFDA (Saudi Food & Drug Authority)
  • Saudi National Formulary / MOH (where available)

International

  • WHO Model List of Essential Medicines (verify current edition)
  • US FDA or EU EMA product information (when national SmPC is unavailable)
  • Product labeling (magnesium sulfate)
  • Local torsades, eclampsia, and asthma adjunct protocols