Obstetric agents (magnesium, steroids, tocolytics, fertility)
(Redirected from Terbutaline)
| Drug monograph · NCLEX study reference | |
| Therapeutic class | Obstetric agents |
|---|---|
| Pharmacologic class | Electrolyte and anticonvulsant (magnesium), corticosteroids, beta agonist tocolytic, ovulation stimulant |
| Onset / peak / duration | Magnesium IV onset rapid; betamethasone effect over 24 to 48 hours. |
| Half-life / level | Magnesium therapeutic range for preeclampsia about 4 to 7 mEq/L. |
| Routes | PO (oral), IV, IM |
| High-alert (ISMP) | Yes (magnesium sulfate) |
| Black box warning | Yes (see Safety) |
| Antidote / reversal | Calcium gluconate for magnesium toxicity. |
| Pregnancy / lactation | Used in obstetric care. |
Nursing pharmacology study reference (NCLEX-style monograph). Numeric values are standard teaching ranges for study and must be verified against current manufacturer labeling before clinical use. This is educational content, not prescribing guidance.
Obstetric agents (magnesium, steroids, tocolytics, fertility) — Obstetric agents; Electrolyte and anticonvulsant (magnesium), corticosteroids, beta agonist tocolytic, ovulation stimulant.
Identification
- Therapeutic class: Obstetric agents.
- Pharmacologic class: Electrolyte and anticonvulsant (magnesium), corticosteroids, beta agonist tocolytic, ovulation stimulant.
Pharmacology
- Mechanism of action: Magnesium prevents and treats eclamptic seizures and relaxes the uterus; corticosteroids accelerate fetal lung maturity; terbutaline relaxes the uterus; clomiphene stimulates ovulation.
- Onset / peak / duration: Magnesium IV onset rapid; betamethasone effect over 24 to 48 hours.
- Half-life / therapeutic level: Magnesium therapeutic range for preeclampsia about 4 to 7 mEq/L.
Clinical use
- Indications: Preeclampsia and eclampsia seizure prevention and preterm labor (magnesium), fetal lung maturity (steroids), short-term tocolysis (terbutaline, magnesium), infertility (clomiphene).
- Usual dose, route, frequency: Magnesium IV loading then infusion; betamethasone IM two doses; clomiphene PO for 5 days.
- Maximum dose / adjustments: Titrate magnesium to level and reflexes; reduce in renal impairment.
Safety
- Contraindications: Magnesium in heart block or myasthenia gravis; terbutaline for prolonged tocolysis.
- Black box warning: Terbutaline carries a boxed warning against prolonged tocolytic use (maternal cardiac events and death).
- Interactions: Magnesium with calcium channel blockers (hypotension) and neuromuscular blockers (enhanced).
- Pregnancy / lactation: Used in obstetric care.
- High-alert: Yes (magnesium sulfate).
Adverse effects
- Common side effects: Magnesium causes flushing, warmth, and lethargy; terbutaline causes tachycardia and tremor.
- Serious effects to report: Magnesium toxicity (loss of deep tendon reflexes, respiratory depression, low urine output, cardiac changes).
- Antidote / reversal: Calcium gluconate for magnesium toxicity.
Nursing process
- Assessment before administration: Deep tendon reflexes, respiratory rate, urine output, blood pressure, magnesium level.
- Interventions during therapy: Monitor reflexes, respirations (above 12), and urine output (above 30 mL/hr) during magnesium; keep calcium gluconate at the bedside.
- Monitor: Magnesium level, reflexes, respirations, urine output, fetal status.
- Evaluation / expected outcome: Seizure prevention or lung maturity achieved.
Patient teaching
- Patient teaching: Magnesium causes warmth and flushing; report difficulty breathing; betamethasone protects the baby's lungs.
- Notify provider if: Not applicable for inpatient magnesium (continuous monitoring); team manages toxicity.
- Administration tips: Magnesium is high-alert; bedside calcium gluconate; monitor reflexes and respirations.