ABC | Volume 114, Nº4, April 2020

Statement Luso-Brazilian Position Statement on Hypertensive Emergencies – 2020 Arq Bras Cardiol. 2020; 114(4)736-751 Table 3 – Pharmacokinetic and pharmacodynamic properties of the main antihypertensive medications for parenteral use Medications Method of administration and dosage Start Duration Advantages Disadvantages Nitroglycerin (nitric oxide donor with arterial and venous vasodilation effects) Continuous infusion 5 to 15 mg/h 2 to 5 min 3 to 5 min Coronary perfusion Headache, variable efficacy, tachyphylaxis Sodium nitroprusside (arterial and venous vasodilator) Continuous infusion 0.5 to 10 μg/kg/min Immediate 1 to 2 min Titration Intoxication by thiocyanate, hypotension, nausea, vomiting, muscle spasm Metoprolol (beta-blocker) Loading dose: 5 mg IV (repeat every 10 min, up to 20 mg if necessary) 5 to 10 min 3 to 4 h Reduction in O 2 consumption Bradycardia, AVB, bronchospasm Labetalol (alpha- and beta-blocker) Loading dose: 20 to 80 mg every 10 min Continuous infusion 2 mg/min (maximum 300 mg/24 h) 5 to 10 min 2 to 6 h Beta-blocker and vasodilator Nausea, vomiting, AVB, bronchospasm, orthostatic hypotension Esmolol (Ultra-fast action, ultra- selective beta-blocker) Loading dose: 500 μg/kg Intermittent infusion: 25 to 50 μg/kg/min ↑ 25 μg/kg/min every 10 to 20 min. Maximum: 300 μg/kg/min 1 to 2 min 1 to 20 min Selective beta-blocker Bradycardia, AVB, bronchospasm Hydralazine (direct-acting vasodilator) 10 to 20 mg IV or 10 to 40 mg IM every 6 h 10 to 20 min IV or 20 to 30 min IM 3 to 12 h Eclampsia or impending eclampsia Tachycardia, headache, vomiting. Worsening of angina and AMI. Beware of increased intracranial pressure Enalaprilat (ACEI) Intermittent infusion: 1.25 to 5 mg every 6 h 15 min 4 to 6 h CHF, acute LVF Hypotension, renal insufficiency Furosemide (loop diuretic) Infusion 5 to 10 min 30 to 90 min CHF, LVF Hypokalemia AMI: acute myocardial infarction; CHF: congestive heart failure; LVF: left ventricular failure; AVB: atrioventricular block; ACEI: angiotensin-converting enzyme inhibitor; IV: intravenous; IM: intramuscular. 5. Hypertensive Encephalopathy Hypertensive encephalopathy is a neurological dysfunction defined by signs and/or symptoms of cerebral edema secondary to sudden and/or sustained BP elevation. It occurs in individuals with chronic hypertension who develop malignant hypertension or in those previously normotensive who may present acute BP elevations due to other mechanisms, progressing with failure in mechanisms of cerebral perfusion autoregulation. Hypertensive encephalopathy is a diagnosis of exclusion confirmed retrospectively when the neurological condition improves after BP control. 5.1. Clinical Manifestations Hypertensive encephalopathy may present with the insidious onset of holocranial headache, nausea, or vomiting. Subsequently, changes in mental status and visual field, photopsia, blurred vision, visual hallucinations, generalized seizures, hyperreflexia, and signs of intracranial hypertension may develop. 29,30 By the time the neurological manifestations emerge, the DBP is usually above 125 mmHg. The resolution of this condition, from both clinical and imaging standpoints, occurs on average several weeks after BP control. The occurrence of a persistent deficit is a sign of focal neurological injury. 5.2. Diagnosis Magnetic resonance imaging is the most valuable diagnostic test. T2-weighted sequences show hyperintense white matter lesions with preferential involvement of the parieto-occipital regions. The territory irrigated by the vertebrobasilar system can be compromised in more severe cases. Hyperintense signal in apparent diffusion coefficient allows for the visualization of vasogenic edema. 31 Laboratory tests may show thrombocytopenia, microangiopathic hemolytic anemia, proteinuria, and increased plasma creatinine and liver enzymes. On computed tomography, focal or diffuse hypodensities in the white matter and cortex are common, along with signs of edema. Electroencephalography shows generalized slowing with loss of alpha rhythm, or epileptiform activity if seizures occur. 5.3. Treatment The goal is to reduce the average BP by approximately 10 to 15% in the first hour and by no more than 25% at 741