Table 3.

Antihypertensive treatment in pregnancy

Typical doseCautionsPeak onsetConsiderations for pregnancy
Oral medications
Labetalol100–800 mg TDSAsthma
Decompensated heart failure
2–4 hoursFirst line in UK as licensed for pregnancy
Monitor for neonatal hypoglycaemia
Modified-release nifedipine10–40 mg BDImmediate-release and sublingual preparations are not used in UK due to unpredictable hypotensive effect1.5–4.2 hoursMost common second-line treatment
Racial differences in blood pressure response to calcium channel blockers have not been investigated in pregnancy
Amlodipine5–10 mg ODPrevious intolerance6–8 hoursLimited data for pregnancy but no evidence of harm
Methyldopa250 mg – 1 g TDSLiver dysfunction
Mood disorder
6–9 hoursNot used postpartum due to exacerbation of depression
Doxazosin2–16 mg total daily dosePostural hypotension2–3 hoursLimited data but no evidence of harm
Accumulation in milk in animal studies not replicated in limited human data
Prazosin0.5–6 mg BD–TDSPostural hypotension30–90 minutesLimited data but no evidence of harm in pregnancy and lactation
Intravenous medications
LabetalolBolus: 20–50 mg over 1–2 minutes repeated every 10 minutes to a maximum of 4 bolus doses.
Infusion: 20 mg/hour titrated (double, maintain or halve) as required every 30 minutes to a maximum dose of 160 mg/hour
Decompensated heart failure
5–10 minutesNeeds invasive BP monitoring
Consider other aspects of care for pre-eclampsia with severe features:
Intravenous magnesium
Fluid balance/restriction
Fetal wellbeing
Plans for delivery
HydralazineBolus: 5 mg over 10 minutes can be repeated in 20–30 minutes. Follow with infusion if required
Infusion: 5 mg/hour, titrated to blood pressure
Maternal tachycardia (heart rate >120 bpm)15–30 minutesNeeds invasive BP monitoring
Reduction in blood pressure less predictable than with labetalol
Careful fluid balance: caution with plasma expansion due to the risk of pulmonary oedema in pre-eclampsia
Enalapril2.5–10 mg BD orallyContraindicated in pregnancy
Acute kidney injury
4–6 hoursFetotoxic in 2nd and 3rd trimester
Used for postpartum hypertension including lactation
Hypothesised benefit in regression of proteinuria and cardiac remodelling after pre-eclampsia
  • BD = twice daily; BP = blood pressure; bpm = beats per minute; OD = once daily; TDS = three times daily.