From the Research
Metoprolol can be used during pregnancy when the benefits outweigh the risks, typically for conditions like hypertension, arrhythmias, or preeclampsia, with a recommended dosing of 25-100 mg twice daily for immediate-release formulations or 50-200 mg once daily for extended-release formulations, with the lowest effective dose being preferred, as suggested by 1.
Key Considerations
- Dosing should be individualized based on the patient's blood pressure response and heart rate, with careful monitoring throughout pregnancy.
- Metoprolol is generally considered one of the safer beta-blockers during pregnancy as it has been well-studied, with minimal placental transfer compared to other beta-blockers, as noted in 2 and 3.
- Potential risks include fetal growth restriction, neonatal hypoglycemia, and bradycardia, particularly when used in the third trimester, as mentioned in 1.
- Blood pressure and fetal growth should be monitored regularly during treatment, as recommended by 2 and 3.
- If metoprolol is continued until delivery, newborns should be monitored for hypoglycemia and bradycardia for 48-72 hours after birth, as suggested by 1.
- The medication is compatible with breastfeeding, as only small amounts pass into breast milk, as noted in 3 and 1.
Pharmacokinetics and Monitoring
- The pharmacokinetics of metoprolol during pregnancy and lactation have been studied, with results indicating that metoprolol apparent oral clearance is significantly higher in mid-pregnancy and late pregnancy compared to postpartum, as shown in 1.
- Relative infant exposure to metoprolol through breast milk is less than 1.0% of maternal weight-adjusted dose, as reported in 1.
- Clinicians should be prepared to make aggressive changes in dosage (dose and frequency) or consider using an alternate beta-blocker if inadequate clinical responses are encountered, as suggested by 1.