INTRODUCTION — Severe hypertension (often defined as systolic blood pressure ≥180 mmHg and/or diastolic blood pressure ≥120 mmHg) can produce a variety of acute, life-threatening complications, which are considered hypertensive emergencies [1,2]. These include hypertensive encephalopathy, retinal hemorrhages, papilledema, and acute renal failure (table 1). (See "Hypertensive emergencies: Malignant hypertension and hypertensive encephalopathy", for a review of the manifestations and treatment of hypertensive emergencies).

Some patients with an equivalent degree of hypertension are relatively asymptomatic (other than perhaps headache) and have no acute signs of end-organ damage. This entity is called hypertensive urgency, and as with hypertensive emergencies, it seems to occur most commonly among patients who have been nonadherent with their chronic antihypertensive regimen. Severe hypertension can also occur in medication-adherent patients following ingestion of large quantities of salt [3]. (See "Initial evaluation of the hypertensive adult" and "Hypertension in kidney disease".)

This topic reviews the treatment of severe asymptomatic hypertension, or hypertensive urgency. The evaluation of the patient with hypertension, the treatment of hypertensive emergency, and the treatment of the pregnant woman with severe hypertension are discussed separately. (See "Hypertensive emergencies: Malignant hypertension and hypertensive encephalopathy" and "Treatment of specific hypertensive emergencies" and "Management of hypertension in pregnancy" and "Expectant management of severe preeclampsia".)

The recommendations in this topic review only apply to patients without signs of end-organ damage. The evaluation of the patient with severe hypertension is discussed separately. (See "Initial evaluation of the hypertensive adult", section on 'The basic workup' and "Hypertensive emergencies: Malignant hypertension and hypertensive encephalopathy", section on 'Clinical manifestations'.)

TREATMENT — The optimal management of patients with severe asymptomatic hypertension is unclear. The blood pressure reading should be quickly confirmed with a repeat measurement utilizing proper technique. (See "Technique of blood pressure measurement in the diagnosis of hypertension".)

Blood pressure reduction goals — The rapidity with which blood pressure should be brought to safe levels (eg, <160/100 mmHg) is controversial. A relatively rapid reduction in blood pressure (BP) was recommended in the past. However, in the absence of symptoms a more gradual reduction in pressure is suggested. While a variety of oral therapeutic modalities have been used, including clonidine, sublingual nifedipine, and oral or sublingual captopril [4-6], sublingual nifedipine is now contraindicated in this setting. In many cases, however, blood pressure may decline spontaneously simply with rest in a quiet room.

Furthermore, there is no proven benefit from rapid reduction of the blood pressure in patients with severe asymptomatic hypertension [1,2,7-9]. In fact, cerebral or myocardial ischemia or infarction can be induced by aggressive antihypertensive therapy if the blood pressure falls below the range at which tissue perfusion can be maintained by autoregulation [10-12]. This has been most often described with sublingual nifedipine; the degree of blood pressure reduction cannot be controlled or predicted, and severe ischemic complications have ensued [11]. Given these concerns, as noted above, sublingual nifedipine should not be used in this setting.

Thus, in the absence of signs of acute end-organ damage, the goal of management is to reduce the blood pressure to ≤160/100 mmHg over several hours to days [1,9]. This is based on the adverse effects observed with faster correction and/or lower achieved blood pressures [8,10,11].

The individual patient's risk for an adverse event and the probable duration of severe hypertension must be considered when deciding how quickly to reduce the blood pressure. As an example, an elderly patient may be at particularly high risk for cerebral or myocardial ischemia from excessively rapid reduction of blood pressure. In such a patient, who often will have a high pulse pressure (eg, diastolic blood pressure <90 mmHg with systolic blood pressure ≥180 mmHg), the initial goal blood pressure of ≤160/100 mmHg may need to be achieved even slower.

General strategies — All patients should be provided a quiet room to rest; this can lead to a fall in BP of 10 to 20 mmHg or more. The approach varies depending on whether the patient has already been treated for hypertension or is untreated.

Previously treated hypertension — Among patients already treated with antihypertensive medications, the following (depending on the circumstances) may be appropriate interventions [7,8]:

• Increase the dose of existing antihypertensive medications, or add another agent.
• Reinstitution of medications in non-adherent patients.
• Addition of a diuretic, and reinforcement of dietary sodium restriction, in patients who have worsening hypertension due to high sodium intake.

Untreated hypertension — In the previously untreated patient, several options are available. The approach should take into consideration the individual patient's risk with persistence of severe hypertension, the likely duration of severe hypertension, and of cerebrovascular or myocardial ischemia with rapid reduction in blood pressure [1,7,8,13]:

• Relatively rapid initial blood pressure reduction (over several hours). We use one of the following agents: oral furosemide (if the patient is not volume depleted) at a dose of 20 mg (or higher if the renal function is not normal); a small dose of oral clonidine (0.2 mg); or a small dose of oral captopril (6.25 or 12.5 mg).

Following administration of one of these agents, the patient is observed for a few hours, to ascertain a reduction in blood pressure of 20 to 30 mmHg. Thereafter, a longer acting agent is prescribed (see below) and the patient is sent home to follow up within a few days. The drop in blood pressure may take relatively longer with captopril, and may be too large among patients with hemodynamically significant unilateral renal artery stenosis.

We prefer this approach in patients with known aortic or intracranial aneurysms. This may be the optimal approach in most patients, however this is not proven, and it is often not feasible to provide medications and observe for several hours.

• Blood pressure reduction over one to two days. There are no data supporting the use of a particular agent in this setting although we generally do not begin therapy with extended release preparations or with a diuretic alone. Depending on the patient, a calcium channel blocker (but not sublingual nifedipine), beta blocker or angiotensin converting enzyme (ACE) inhibitor or receptor blocker can be started. Examples in these categories are oral nifedipine 30 mg once daily (of the long-acting preparation), oral metoprolol XL 50 mg daily, or ramipril 10 mg once daily.

The choice of agent should take into consideration the type of antihypertensive agent that is most appropriate in the long term (eg, calcium channel blockers and thiazide-like diuretics are preferred over ACE inhibitors and beta blockers as monotherapy in blacks), and underlying conditions that may be favorably or adversely affected by the antihypertensive agent (table 2). (See "Choice of therapy in essential hypertension: Recommendations" and "Indications for use of and contraindications to specific antihypertensive drugs" and "Treatment of hypertension in blacks", for discussions of preferred agents in specific patients).

Some experts initiate therapy with two agents or a combination agent, one of which is a thiazide diuretic. The rationale is that most patients with blood pressure ≥20/10 mmHg above goal will require two or more antihypertensive agents in order to achieve the goal blood pressure [1,2,14,15]. It is unlikely that a diuretic in combination with a modest dose of another agent will cause a dangerous reduction in the blood pressure; however, initiation of two agents simultaneously must be done with close blood pressure follow-up, since the full effects of both agents may not occur for a few days, and adverse consequences may ensue if the blood pressure is lowered too quickly. This is particularly true among patients with cerebrovascular disease in whom more cautious blood pressure reduction is warranted.

Monitoring and follow-up — The patient with severe asymptomatic hypertension is usually managed in the emergency room, since exclusion of acute end-organ damage requires laboratory testing, and the patient may require administration of medications and several hours of observation. However, the patient can often be safely managed in the physician's office if the evaluation and management can be carried out. (See "Initial evaluation of the hypertensive adult".)

The management of a patient who does not have established follow-up is difficult. Rarely, such patients may require admission. In addition, patients at high risk for cardiovascular events (eg, long-standing diabetes, known coronary artery disease or prior stroke), should probably be admitted. (See "Cardiovascular risks of hypertension", section on 'Additive effects of multiple risk factors'.)

Ideally, the patient should be observed for a few hours to ascertain that the blood pressure is stable or improving, and that indeed they are asymptomatic. If so, the patient can be sent home with close follow-up over the subsequent days, directed towards evaluation for symptoms related to hypertension or hypotension, and adjustment of medications to achieve the initial blood pressure goal of ≤160/100 mmHg. In reliable patients who can monitor their blood pressure at home, close phone follow-up may substitute for direct physician visits. If the patient does not have a physician, follow-up may need to be in the emergency room or other acute care setting.

Over subsequent weeks and months, the dose and selection of medications should be adjusted as needed to achieve desired goals (eg, <140/90 or <130/80 mmHg, as appropriate), preferably with longer acting agents. (See "Choice of therapy in essential hypertension: Recommendations" and "Indications for use of and contraindications to specific antihypertensive drugs" and "What is goal blood pressure in treatment of hypertension?".)

INFORMATION FOR PATIENTS — Educational materials on this topic are available for patients. (See "Patient information: High blood pressure in adults" and "Patient information: High blood pressure treatment in adults" and "Patient information: High blood pressure, diet, and weight".) We encourage you to print or e-mail these topic reviews, or to refer patients to our public web site, www.uptodate.com/patients, which includes these and other topics.

SUMMARY AND RECOMMENDATIONS

Severe hypertension (systolic blood pressure ≥180 mmHg or diastolic blood pressure ≥120 mmHg), with no acute signs of end-organ damage, is often called hypertensive urgency. (See "Initial evaluation of the hypertensive adult".)

If there are signs or symptoms of acute end-organ damage, the condition is considered a hypertensive emergency and is treated more aggressively (table 1). (See "Hypertensive emergencies: Malignant hypertension and hypertensive encephalopathy".)

There is no proven benefit from rapid reduction of the blood pressure in patients with severe asymptomatic hypertension, and myocardial or cerebral ischemia can be precipitated by overly rapid blood pressure lowering.

In all patients presenting with severe hypertension, we suggest repeating the blood pressure after rest in a quiet room.

We suggest an initial goal of reducing the blood pressure to ≤160/100 mmHg over several hours to days with conventional oral therapy (Grade 2B). The optimal rapidity with which blood pressure is lowered is controversial, and must take into consideration the individual patient's risk for an ischemic event. (See 'Treatment' above.)

For previously treated patients, we suggest adjusting their existing medication regimen, or reinstituting their medications (if nonadherent).

For most previously untreated patients, we suggest beginning a low dose of a calcium channel blocker, beta blocker or ACE inhibitor, but not a diuretic alone (Grade 2B). Suggested initial agents and doses for the average sized adult in these categories are oral nifedipine XL 30 mg once daily (of the long-acting preparation), oral metoprolol XL 50 mg daily, or ramipril 10 mg once daily. Keep in mind that a recent Cochrane analysis on this topic does not signify any particular agent as preferred for initial therapy in this setting [16]. Specifically, there is no evidence from randomized controlled trials that demonstrates that antihypertensive drugs reduce mortality or morbidity in patients with hypertensive emergencies. Furthermore, there is insufficient evidence from randomized trials to determine which drug or drug class is most effective in reducing mortality and morbidity.

The choice of agent should take into consideration patient characteristics and comorbid conditions, which influence optimal long-term therapy (table 2). Some physicians begin therapy with two agents (one of which is a thiazide diuretic) in reliable patients. (See "Choice of therapy in essential hypertension: Recommendations" and "Indications for use of and contraindications to specific antihypertensive drugs" and "Treatment of hypertension in blacks", for discussions of preferred agents in specific patients).

For all patients, we recommend initial close follow-up (every one to two days). Follow-up is directed towards evaluation for symptoms of either hypertension or hypotension, and attainment of the initial blood pressure goal of ≤160/100 mmHg. In reliable patients who can monitor their blood pressure at home, close phone follow-up may substitute for direct physician visits.

In the patient who does not have certain follow-up, particularly patients at high risk for cardiovascular or cerebrovascular disease, we suggest admission to the hospital for initial management. (See "Cardiovascular risks of hypertension", section on 'Additive effects of multiple risk factors'.)

Over the course of weeks to months, the dose and selection of medications is modified to achieve desired goals (eg, <140/90 or <130/80 mmHg, as appropriate), usually with longer acting agents. (Grade 2B). (See "Choice of therapy in essential hypertension: Recommendations" and "Indications for use of and contraindications to specific antihypertensive drugs" and "What is goal blood pressure in treatment of hypertension?".)