MAGNESIUM SULFATE IV

I. Indications

1. Preterm Labor for tocolysis or prevention of cerebral palsy for preterm birth < 30wks (click link for details)
2. Preeclampsia

II. Contraindications

1. Renal failure
2. Hypocalcemia
3. Myasthenia gravis
4. Don't combine with calcium-channel blockers

III. Dosing guidelines:

1. Check serum Cr first!! (Mg is excreted by kidneys)  If high, lower infusion rate
2. First give NS 500ml over 30min then bolus 4-5g over 20min then 2-3.5g/h, then 2-3g/h titrated to DTR's & serum Mg levels
   1. One protocol used for tocolysis calls for, after bolus is given, increasing rate by 0.5/h Q15-30min until sig. side effects or ctx stop; then decrease by 0.6g/h Q1h to min of 2g/h as long as ctx absent
3. Target levels = 4-8mg/dL
4. Consider checking levels 2h post-loading then Q4-6h
5. Evaluate Qhour:

1. DTR's (should be present)--earliest sign of toxicity
2. Respirations (should be >12/minute)
3. Urine output (should be >30cc/h)

IV. Adverse reactions:

1. Nausea
2. Flushing
3. Dizziness
4. Dry mouth
5. Headache
6. Somnolence
7. Blurred vision
8. Weakness and hyporeflexia (lose DTR's at 10mg/dL)
9. Respiratory depression (respiratory arrest usually occurs at 12mg/dL)
10. Oliguria
11. Pulmonary edema

V. Antidote: CaGluconate 1gIV slow push over 3min; have @ bedside