OB Pharmacology NSC

Obstetric Pharmacology Magnesium Sulfate  Actions • Not clearly understood • Seems to decrease release of acetylcholine at neuromuscular junction • Depresses central nervous system • Causes mild vasodilation – Decreases blood pressure – Improves placental blood flow Magnesium Sulfate  Indications • Anticonvulsant effects in: – Pre-eclampsia – Eclampsia Magnesium Sulfate  Contraindications • Renal disease • Cardiac failure • AV conduction defects • Myasthenia gravis Magnesium Sulfate  Adverse effects • Muscle weakness • Respiratory depression • Hypotension • Slowed cardiac conduction/AV blocks Magnesium Sulfate  Antidote to toxic effects • Calcium Magnesium Sulfate  Dose • Initial: 4 to 8 gm IV over 20 minutes • Maintenance: 1 to 2 gm/hr Pitocin  Action • Synthetic oxytocin • Stimulates uterine smooth muscle contraction Pitocin  Indication • Control of postpartum hemorrhage Pitocin  Contraindication • Do not administer until after baby, placenta fully delivered • May cause trapping of placenta or second twin in uterus Pitocin  Adverse effects • Nausea, vomiting • Cardiac arrhythmias • Fluid retention with water intoxication • Transient vasodilation, reflex tachycardia Pitocin  Dose • 10 to 40 units in 1 L of crystalloid • Infuse to: –Sustain uterine contraction –Control hemorrhage