Antihypertensive treatment in pregnancy
| Typical dose | Cautions | Peak onset | Considerations for pregnancy | |
|---|---|---|---|---|
| Oral medications | ||||
| Labetalol | 100–800 mg TDS | Asthma Decompensated heart failure | 2–4 hours | First line in UK as licensed for pregnancy Monitor for neonatal hypoglycaemia |
| Modified-release nifedipine | 10–40 mg BD | Immediate-release and sublingual preparations are not used in UK due to unpredictable hypotensive effect | 1.5–4.2 hours | Most common second-line treatment Racial differences in blood pressure response to calcium channel blockers have not been investigated in pregnancy |
| Amlodipine | 5–10 mg OD | Previous intolerance | 6–8 hours | Limited data for pregnancy but no evidence of harm |
| Methyldopa | 250 mg – 1 g TDS | Liver dysfunction Mood disorder | 6–9 hours | Not used postpartum due to exacerbation of depression |
| Doxazosin | 2–16 mg total daily dose | Postural hypotension | 2–3 hours | Limited data but no evidence of harm Accumulation in milk in animal studies not replicated in limited human data |
| Prazosin | 0.5–6 mg BD–TDS | Postural hypotension | 30–90 minutes | Limited data but no evidence of harm in pregnancy and lactation |
| Intravenous medications | ||||
| Labetalol | Bolus: 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 | Asthma Decompensated heart failure | 5–10 minutes | Needs invasive BP monitoring Consider other aspects of care for pre-eclampsia with severe features: Intravenous magnesium Fluid balance/restriction Fetal wellbeing Plans for delivery |
| Hydralazine | Bolus: 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 minutes | Needs 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 |
| Postpartum | ||||
| Enalapril | 2.5–10 mg BD orally | Contraindicated in pregnancy Hyperkalaemia Acute kidney injury | 4–6 hours | Fetotoxic 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.