A marked elevated systolic blood pressure SBP ≥ 180mmHg and/or a diastolic DBP ≥130mmHg associated with life threatening situations among one of the following;

• Unstable angina/myocardial infarction

• Hypertensive encephalopathy e.g. severe headache, visual disturbances, confusion, coma or seizures which may result in cerebral haemorrhage

• Acute left ventricular failure with severe pulmonary oedema (extreme breathlessness at rest)

• Excessive circulating catecholamine: e.g. pheochromocytoma – rare cause of emergency; food or drug interaction with monoamine oxidase inhibitors

• Rapidly progressive renal failure

• Acute aortic dissection

• Eclampsia and severe pre-eclampsia

  
  

Pharmacological

Goal: immediate lowering of BP with parenteral (preferably IV infusion) medicines and strict haemodynamic monitoring in a high dependency or intensive care unit.

At a primary facility: arrange immediate referral to the regional referral hospital and call the ambulance, and give IV/IM hydralazine while waiting.

• C: Labetalol IV 20 mg stat, then 20–80 mg every 10 minutes as needed, OR 0.5 mg/minute infusion increased to 1–2 mg/minute (up to 4 mg/minute), maximum 300 mg/day. Onset 5–10 minutes; duration 3–6 hours. Contraindicated in advanced aortic stenosis; avoid in asthma.

• AND/OR S: Nitroglycerin (glyceryl trinitrate) IV infusion – best in coronary ischaemia and acute coronary syndromes: start 5–10 micrograms/minute, increase as needed (usual 5–100, up to more than 200 micrograms/minute). Onset immediate; duration 1–5 minutes.

• AND/OR B: Hydralazine IV 5 mg slow push over 1–2 minutes, repeat 5–10 mg as needed.

• Before or during referral (Figure 20.3): B: hydralazine IV/IM 10 mg (10 mg in 1 ml diluted in 9 ml normal saline or Ringer's lactate), repeated every 30 minutes if needed, maximum total 300 mg per day.

• OR S: Nicardipine 10 mg/hour continuous IV infusion, increased by 2.5 mg/hour every 15 minutes to a maximum of 15 mg/hour, keeping SBP below 220 mmHg and DBP below 110 mmHg.

⚠ Dose check note: STG 2026 prints hydralazine IV/IM "10 mg, repeat every 30 minutes if needed (max total dose = 300 mg per day)". WHO guidance for severe hypertension gives hydralazine 5 mg IV slowly, repeated every 30 minutes until BP is controlled, to a maximum of about 20–30 mg per episode; the same STG gives 5–20 mg (maximum 30 mg) for perioperative hypertension. Cross-check this dose against the WHO recommendation before prescribing.