TOC   |  DRUGS |   ACP Drug Resource | Medline Drugs Info Site    

HYPERTENSION CRISIS       See:   Hypertension Page |  Malignant_hypertension   |  Secondary Hypertension  | Resistant Hypertension  

REF:  The Reference Card of the Joint National Committee (JNC 7) 2003 | ACP Medicine Best Dx/Best Rx 2006  
Hypertension Crisis   |  

See also Malignant_hypertension (rapidly rising blood pressure - systolic blood pressure > 200 mmHg, diastolic blood pressure > 120-140 mmHg )

Definition

  • Severe elevation in blood pressure, with diastolic blood pressure (DBP) > 120-130 mmHg.
  • Hypertensive Emergency is defined as a clinical setting where BP must be reduced effectively within minutes to <1hour, such as
    accelerated & malignant hypertension, hypertensive encephalopathy, & severe diastolic hypertension (120-160 mmHg) that is associated with acute pulmonary edema, ischemic chest pain, dissecting aortic aneurysm, or intracerebral hemorrhage,  papilledema (+/ ), evidence of renal function deterioration, or evidence of neurologic dysfunction, etc.
  • Hypertensive Urgency is defined as a clinical setting of severe hypertension  with minimal or no symptoms, where severe elevation of BP are not causing immediate end-organ damage but should be effectively lowered within 24 hours to reduce potential risk to the patient.

Symptoms as:

  • Headache, Visual Changes, Papilledema
  • Chest Pain (MI), Pain to Back (Dissection)
  • Abdominal Pain - abdominal aneurysmal dissection
  • Flank Pain - renal disease
  • Mental Status Changes - stroke, leukoencephalopathy

Top

ACP PIER 2006                                                                      

Approach to Hypertensive Emergency/Crisis          

Distinguish between a hypertensive emergency and a pseudocrisis in patients with markedly elevated BP.

  • Do not use parenteral or sublingual drugs to treat markedly elevated BP (>180/110 mm Hg to 220/120 mm Hg) in the absence of symptoms or progressive target organ damage.
  • Use the following treatment approaches:
    • Administer one or more rapid-onset oral antihypertensive drugs (e.g., furosemide, propranolol, captopril, clonidine, or nicardipine);
      once BP is less than 180/110 mm Hg
      , administer a longer-acting formulation and recheck the BP within 48 hours.
    • Administer a longer-acting oral formulation from the start and recheck BP in 48 hours.

Identify when a hypertensive BP reading may constitute an emergency.

  • Measure BP repeatedly and assess the possibility of ongoing or imminent target organ damage.
  • Consider hospitalizing a patient with hypertensive emergency for parenteral antihypertensive medication when BP is sufficiently elevated to cause target organ damage (imminent) or is judged to have caused or played a role in present (ongoing) target organ damage.
    Specifically, considering hospitalizing hypertensive patients with:
    • Coronary disease and crescendo angina
    • Heart failure with increasing shortness of breath
    • Abrupt worsening of renal function
    • Headache, blurred vision, and increasing disorientation or confusion
    • Past hypertensive end-organ damage
    • Recent vascular surgery
    • Organ transplantation
    • Known aortic aneurysm or a tearing sensation between the scapulae
  • A child with previously normal BP may have a hypertensive emergency at a BP not considered particularly worrisome in an adult. Use clinical judgment to determine need for hospitalization.
  • A pregnant woman with previously normal or low BP may have a hypertensive emergency at a BP not considered particularly worrisome in a nonpregnant adult. Use clinical judgment to determine need for hospitalization.
  • Measure the BP more than once or twice and carefully track it before declaring an “emergency.” The duration of this tracking will vary according to clinical presentation.
  • Monitor the BP in a setting where intravenous antihypertensive drugs can be given rapidly.

Quick Exam in Severe Hypertension   Yes or  No

  • Are pressures equal in the arms?
  • Are femoral pulses present?
  • Is grade III or IV retinopathy present?
  • Is the patient oriented?
  • Are pupils equally dilated?
  • Is the neck stiff?
  • Are rales or an S3 present?
  • Are abdominal bruits present?
  • Are there overt neurologic deficits?

Quick History in Severe Hypertension     Yes or No

  • Was antihypertensive therapy recently interrupted?
  • Are neurologic symptoms present?
  • Were they sudden in onset: i.e., over minutes to hours?
  • Did they occur gradually over days?
  • Is severe headache present?
  • Have visual disturbances occurred?
  • Has nausea or vomiting occurred?
  • Is severe dyspnea present?
  • Is the patient pregnant?
  • Does the patient have worsening angina?
  • Is the patient post- vascular surgery (including CABG)?
  • Has the patient taken sympathomimetics or cocaine?
  • Is the patient taking a MAOI antidepressant ?

Situations In Which Severe Hypertension Constitutes a Crisis

  • Heart/Vascular
    • Left ventricular failure
    • MI
    • Unstable angina
    • After vascular surgery or CABG
    • Aortic dissection
  • Brain
    • Hypertensive encephalopathy
    • Subarachnoid hemorrhage
    • Intracranial hemorrhage
    • Thrombotic stroke with severe hypertension
  • Miscellaneous
    • Severe catecholamine excess:
      • Pheochromocytoma
      • Clonidine withdrawal
      • Tyramine/MAOI interaction
      • LSD/cocaine/phencyclidine/phenylpropanolamine use
    • Eclampsia in pregnancy

Antihypertensive Agents That Are Useful in Hypertensive Crises to guide treatment of patients with:

  • Markedly elevated BP and high intracranial pressure
  • Progressive azotemia
  • Coronary ischemia
  • Acute left ventricular failure
  • Eclampsia
  • Suspected aortic dissection
  • Catecholamine excess
  • Suspected aortic dissection, and in the perioperative setting

   

Top

EMERGENCY TREATMENT OF HYPERTENSIVE CRISIS                              
Antihypertensive Agents That Are Useful in Hypertensive Crises
  • Nitroprusside (Nipride)  IV 
    Initial dose 0.3 µg/kg/min (Max dose 10µg/kg/min) Onset of action <1 minute, duration <2 minutes
    Best use for  Encephalopathy, left ventricular failure, aortic dissection (with ?-blocker)
    Major side effects: Cyanide/thiocyanate toxicity (thiocyanate level>10 mg/dl is toxic; >20 mg/dl may be fatal) ; hypotension, N&V, apprehension, convulsion, twitching, psychosis, dizziness, etc.   It has decreased efficacy in renal failure
  • Nitroglycerin IV
    Initial dose 5 µg/min (Max dose 100 µg/min) Onset of action <5 minutes, duration <5 minutes
    For use for Unstable angina, MI.  Excellent for titrating blood pressure in setting of coronary ischemia
    Major side effect: headache, tachycardia, vomiting, methemoglobinemia
  • Labetalol (Trandate) IV
    Mixed alpha/beta blocker, excellent for most hypertensive emergencies.
    First or second line for eclampsia; excellent in catecholamine surges
    Initial dose :20 mg IV bolus over 2 minutes, then 20- 80 mg q10 min prn, or Continuous infusion at 0.5-2.0 mg/min (Max dose 300 mg),
    Onset of action <5 minutes, duration 1-4 hours, but variable
    Best use for Stroke, intracranial hemorrhage
    Side effects: Nausea Fatigue, dizziness, scalp tingling
    Contraindication: Asthma or bronchospasm, overt cardiac failure, >first-degree heart block, severe bradycardia
  • Diazoxide (Hyperstat) IV
    Initial dose: 1-3 mg/kg (up to 150 mg) IV bolus q5-15 min over 5 minutes until BP is controlled (Max dose 600 mg),
    Onset of action <2 minutes, duration 6-12 hours
    Side effects: — Profound hypotension Elevated heart rate, elevated glucose, sodium retention
    Contraindication: Thiazide allergy
  • Nicardipine (Cardene) IV
    Initial dose: 5 mg/h (Max dose 15 mg/h), Onset of action <1 hour, duration <1 hour
    Best use for Vascular surgery, subarachnoid hemorrhage  
    Side effects: Headache ,Elevated heart rate
    Contraindication: Severe aortic stenosis
  • Enalapril (Vasotec) IV
    Highly variable response; precipitous BP drop in high-renin states, rarely angioedema, hyperkalemia, or acute renal failure.
    Initial dose: 1.25 -5mg IV over 5 min q6h if needed, duration 6 hours
    Best use for Left ventricular failure
    Contraindication: Angioedema
  • Diltiazem (Cardizem) IV
    Initial dose 0.25 mg/kg over 2 min, followed by infusion of 0.35 mg/kg at an initial rate of 10 mg/hour
    Onset:  3-30 min
    Adverse effects: excessive hypotension, flushing
  • Trimethaphan
    Initial dose: 1 mg/min (Max dose 4 mg/min), Onset of action <5 minutes, duration <10 minutes
    Best use for Aortic dissection (with ?-blocker)
    Side effect: Orthostatic hypotension
    Contraindication: Severe volume depletion
  • Hydralazine (Apresoline) IV
    Indicated primarily for eclampsia
    Dose is 10-50 mg IV or IM titrate to effect (onset <20 minutes, duration 3-8 hours)
    Can be given IM as well, 10-50mg (onset 20-30 minutes)
    Onset: 10- 20 min ;  Duration: 3 -8 h
    Adverse effects: tachycardia, flushing, contraindicated in angina or aortic dissection
  • Phentolamine
    Mainly for catecholamine surges as in pheochromocytoma hypertension (pure alpha-adrenergic blockade)
    Dose is 5-15mg IV; onset 1-2 minutes; duration 3-10 minutes
    Side effects: Tachycardia, flushing and headache may occur
  • Esmololol (Breviblock®)
    Mainly for acute aortic dissection, perioperatively, acute coronary ischemia

    May be used with caution in acute MI with depressed LV to modulate heart rate
    Very short half life (2-4 minutes) non-selective ß-blockade
    Dose is 250-500µg/kg/min for 1 minute, then 50-100µg/kg for 4 minutes
    Sequence may be repeated, and continuous drip may be maintained
    Onset of action is 1-2 minutes; 10-20 minute duration
    Very close monitoring is required, and fluid load is large with this agent

Oral Medications for Hypertensive Urgency:

  • Clonidine (Catapres)
    0.2 mg PO, followed by 0.1 mg/hr to total of 0.8 mg until the diastolic BP is <110 mmHg, or reduction in diastolic BP of 20 mmHg or more.
    Onset 30-120 min;  Duration 8-12 h
    Adverse effects: sedation, dry mouth, dizziness, orthostasis, bradycardia
    Contraindicated in pts with sinus bradycardia, sick sinus synd., or heart block.
  • Labetalol (Trandate)
    200-300 mg PO, followed by 100-200 mg q8h
    Onset 1-2h;  Duration 12-24 h
    Adverse effects: bradycardia
  • Furosemide (Lasix)
    20-40 mg PO or IV
  • Nicardipine (Cardene)
    20-40 mg PO tid (Max 120 mg/day) or IV 5 mg/h, increase by 2.5 mg/h q5-15 min to max 15 mg/h.
  • Captopril (Capoten)
    12.5-25 mg PO ,may repeat at intervals of = or > 30-60 min (Typical dose <150mg/d; Max 450 mg/d)

----------------------------------------------------------------------------------------------------------------------------

Distinguish between a hypertensive emergency and a pseudocrisis in patients with markedly elevated BP.

  • Do not use parenteral or sublingual drugs to treat markedly elevated BP (>180/110 mm Hg to 220/120 mm Hg) in the absence of symptoms or progressive target organ damage.
  • Use the following treatment approaches:
    • Administer one or more rapid-onset oral antihypertensive drugs (e.g., furosemide, propranolol, captopril, clonidine, or nicardipine);
      once BP is less than 180/110 mm Hg
      , administer a longer-acting formulation and recheck the BP within 48 hours.
    • Administer a longer-acting oral formulation from the start and recheck BP in 48 hours.

In less than hypertensive crises, but  in hypertension urgency:
one or more rapid-onset oral antihypertensive drugs, as:

  • Furosemide (Lasix) 20-40 mg PO or IV
  • Clonidine 01.-0.2 mg PO
  • Nicardipine (Cardene) 20-40 mg PO tid (Max 120 mg/day) or IV 5 mg/h, increase by 2.5 mg/h q5-15 min to max 15 mg/h.
  • Captopril 12.5-25 mg PO ,may repeat at intervals of = or > 30-60 min (Typical dose <150mg/d; Max 450 mg/d)

 

Top

Causes of Hypertensive Crisis 
  • Chronic hypertension with acute exacerbation (most common)
  • Renovascular hypertension
  • Parenchymal Renal Disease
    • Acute glomerulonephritis
    • Renal Infarction
    • Vasculitis
  • Scleroderma Renal Crisis
  • Drug Ingestion
    • Tricyclic anti-depressants
    • Monoamine Oxidase (MAO) Inhibitors
    • Cocaine
    • Amphetamines
  • Anti-hypertensive drug withdrawal or failed compliance
    • Centrally acting anti-hypertensives (eg. clonidine)
    • Peripheral alpha blockers (eg. prazosin)
    • Beta-Blocker acute withdrawal
  • Pre-eclampsia and Eclampsia
  • Autonomic hyperactivity
    • Guillain-Barre Syndrome
    • Spinal Cord Injury
  • Pheochromocytoma

Top

Top  
Malignant Hypertension (Accelerated hypertension )     REF:  DynaMed 2009

No evidence that antihypertensive drugs reduce mortality or morbidity in patients with hypertensive emergencies (Cochrane Library 2008 Issue 1) update

Description:  rapidly rising blood pressure - systolic blood pressure > 200 mmHg, diastolic blood pressure > 120-140 mmHg

Types:

  • hypertensive urgency if 180/100 - admit to floor, administer PO medications
  • hypertensive emergency if end-organ damage - admit to medical ICU, IV nitroprusside

Who is most affected:  young males

Incidence/Prevalence:  rare, < 5% hypertensive patients

Causes and Risk Factors

Causes:  complication of essential or secondary hypertension

Pathogenesis:

  • produces malignant nephrosclerosis, arteriolar damage
  • renal biopsy would show fibrinoid necrosis of arterioles, necrotizing and/or hyperplastic (onion-skinning) arteriosclerosis, necrotizing glomerulonephritis

Physical Exam:

  1. HEENT: focal retinal hemorrhages and papilledema
    Grade III - flame hemorrhage, cotton-wool spot, < 1:2 A-V ratio
    Grade IV - papilledema: no disc margin, may go blind
  2. Cardiac:  left ventricular (LV) hypertrophy, LV failure
  3. Neuro:  mental status exam changes

Complications of Malignant Hypertension:

  • blindness (macular edema, retinal hemorrhage), encephalopathy, renal damage
  • cerebral hypoperfusion if blood pressure lowered > 40% in initial 24 hours

Prognosis:

  • fatal within 1-2 years from congestive heart failure, stroke or renal failure
  • onion-skinning correlates with renal failure
  • 90% dead in 6 months without treatment  

No evidence that antihypertensive drugs reduce mortality or morbidity in patients with hypertensive emergencies (level 2 [mid-level] evidence)

  • based on Cochrane review limited by heterogeneity
  • systematic review of 15 randomized trials evaluating antihypertensive drugs in 869 patients presenting with hypertensive emergency
  • 2 trials were placebo-controlled, 14 of 15 trials were open-label
  • drug classes evaluated were nitrates (9 trials), ACE inhibitors (7 trials), diuretics (3 trials), calcium channel blockers (6 trials), alpha-1 adrenergic antagonists (4 trials), direct vasodilators (2 trials), and dopamine agonists (1 trial)
  • among 7 trials that reported mortality, 6 deaths occurred but allocated treatment group was not reported for 5 of the deaths
  • insufficient data on clinical outcomes for meta-analysis
  • Reference - systematic review last updated 2007 Oct 19 (Cochrane Library 2008 Issue 1:CD003653)

Top  


Treatment overview:

  • hypertensive urgency if 180/100 - admit to floor, administer PO medications
  • hypertensive emergency if end-organ damage (e.g. aortic dissection or pulmonary edema)
  • admit to medical ICU
  • immediate lowering of blood pressure with IV medication
  • monitor blood pressure with arterial line in ICU

drug of choice based on underlying disease

  • sodium nitroprusside drug of choice in most cases
  • nicardipine and fenoldopam are reasonable alternatives
  • labetalol acceptable in patients without second- or third-degree heart block, bronchospastic disease or bradycardia
  • nitroglycerin drug of choice if cardiac ischemia, angina, or following cardiac bypass surgery
  • phentolamine drug of choice if catecholamine-related hypertensive emergency
  • esmolol drug of choice for aortic dissection or postoperative hypertension
  • hydralazine drug of choice in pregnancy if related to eclampsia

target blood pressure

  • reduce mean arterial blood pressure by 25% within 2 hours
  • reduce minimum diastolic pressure to 100 mmHg within 2-6 hours
  • avoid abrupt decreases in blood pressure
  • in aortic dissection, start with beta blockers and lower systolic blood pressure as much as possible without compromising cerebral, cardiac or renal blood flow

some IV drugs used for severe hypertension

  • esmolol 1 mg/kg over 30 seconds then 150-300 mcg/kg/minute, beta blocker, onset of action 2 minutes, duration 18-30 minutes
  • nicardipine 5-15 mg/hour until target blood pressure then 3-5 mg/hour, calcium channel blocker, onset of action 45 minutes for 50% of maximal effect, duration 30 minutes for 50% decrease in effect
  • nitroprusside 0.5-8 mcg/kg/minute, nitric oxide releaser, onset of action seconds, duration 3-4 minutes
  • fenoldopam 0.1-1.6 mcg/kg/minute, selective dopamine DA1 agonist, onset of action 15 minutes for 50% maximal effect, duration 15 minute for 50% decrease in effect

Top  


Parenteral (IV) vasodilators

sodium nitroprusside (Nipride) 0.25-10 mcg/kg/minute

  • immediate onset, duration 3-5 minutes
  • IV infusion 50 mg/500 ml D5W at 0.3-0.8 mcg/kg/min, titrate to BP, maximum dose 10 mcg/kg/min, maximal dose for 10 min only
  • arteriolar and venous vasodilator
  • drug of choice in hypertensive encephalopathy, hypertension and intracranial bleed, malignant hypertension, hypertension and heart failure, dissecting aortic aneurysm (with propranolol)
  • side effects - hypotension, nausea, vomiting, apprehension, cyanide/thiocyanate toxicity, muscle twitching, methemoglobinemia acidosis, carbon dioxide retention, cutis anserina (goose flesh), abdominal cramping, headache
  • cyanide/thiocyanate toxicity
    • may occur with prolonged (> 48 hours) or too rapid (> 2 mcg/kg/minute) infusion
    • discontinue nitroprusside if serum thiocyanate > 12 mg/dL (206.4 µmol/L) or signs of intoxication (acute psychosis, disorientation, muscle spasms, hyperreflexia)
  • may cause hypoxemia in patients with chronic pulmonary disease by reversing pulmonary vasoconstriction
  • delivery system must be light resistant (e.g tubing wrapped in aluminum foil)

nicardipine (Cardene IV)

  • IV 5 mg/hour, increase by 2.5 mg/hour every 15 minutes up to 15 mg/hour
  • onset 1-5 minutes, duration 3-6 hours, takes 48 hours to reach steady state
  • dihydropyridine calcium channel blocker
  • may cause reflex tachycardia, headache, flushing

clevidipine (Cleviprex) FDA approved for intravenous use in lowering high blood pressure

  • onset 2-4 minutes, druation 5-15 minutes
  • 1-2 mg/hour ingtravenously, up to 4-6 mg/hour (or maximum 16 mg/hour)
  • may cause reflex tachycardia
  • calcium channel blocker
  • costs about $180 per 25 mg vial, more than esmolol, slightly less than nicardipine
  • lipid emulsion containing 2 kcal/mL
  • Reference - Med Lett Drugs Ther 2008 Sep 22;50(1295):73 TOC, Prescriber's Letter 2008 Oct;15(10):56

fenoldopam mesylate (Corlopam)

  • onset 4-5 minutes, duration 10-15 minutes
  • 0.1-1.6 mcg/kg/minute, no bolus, titrate by 0.05-0.1 mcg/kg/min every 15 minutes
  • dopamine D1-like receptor agonist, arteriolar vasodilator, natriuretic and diuretic effects
  • unlike other parenteral antihypertensive agents, fenoldopam maintains or improves renal function
  • available for in-hospital, short-term (up to 48 hours) management of severe hypertension, from Neurex (Monthly Prescribing Reference 1998 Jan;A-23)
  • fenoldopam as effective as sodium nitroprusside in open randomized trial of 153 patients with diastolic BP at least 120 mmHg (Acad Emerg Med 1995;2:959)
  • side effects - hypotension, flushing, dizziness, headache, reflex tachycardia, nausea, hypokalemia, increased intraocular pressure
  • safety with beta blocker not established, may cause unanticipated degree of hypotension
  • contraindicated if allergy to sulfites
  • review of fenoldopam can be found in N Engl J Med 2001 Nov 22;345(21):1548

nitroglycerin (Nitro-bid IV)

  • onset 2-5 minutes, duration 5-10 minutes
  • 5-100 mcg/min as IV infusion
  • venous >> arteriolar vasodilator
  • side effects - headache, tachycardia, vomiting, flushing, methemoglobinemia, tolerance with prolonged use
  • requires special delivery system due to drug binding to PVC tubing

diazoxide (Hyperstat)

  • onset 1-5 minutes, duration 6-12 hours
  • 1-3 mg/kg (maximum 150 mg) IV every 5-15 minutes or IV infusion at 15-30 mg/min until desired effect
  • arteriolar vasodilation
  • second drug of choice in hypertensive encephalopathy, malignant hypertension
  • contraindications - ischemic heart disease, intracranial hemorrhage, dissecting aneurysm, pulmonary edema
  • side effects - hypotension, tachycardia, aggravation of angina pectoris, nausea, vomiting, hyperglycemia with repeated injections, sodium retention, cardiac ischemia

hydralazine (Apresoline) 5-10 mg IV every 20-30 minutes

  • onset 10-30 minutes with 10-20 mg IV bolus, onset 20-30 minutes with 10-40 mg IM
  • duration 2-6 hours
  • 10-40 mg IM/IV every 4-6 hours prn
  • mechanism of action - vasodilation of arterioles
  • drug of choice in eclampsia
  • contraindication - hypertension with heart failure, cardiac ischemia, angina, aortic dissection
  • side effects - tachycardia, cardiac ischemia, headache, vomiting, aggravation of angina pectoris, flushing

enalaprilat (Vasotec IV)

  • onset 15-30 minutes, peak effect 4 hours, duration 6-12 hours
  • 0.625 mg IV every 6 hours, response variable and sometimes excessive
  • doses of enalaprilat higher than 0.625 mg are no more effective for initial therapy; 65 patients with hypertensive urgencies (systolic blood pressure > 210 mmHg and/or diastolic blood pressure > 110 mmHg) or emergencies (diastolic blood pressure > 100 mmHg and angina pectoris, hypertensive encephalopathy, or congestive heart failure) were randomized to enalaprilat 0.625 mg vs. 1.25 mg vs. 2.5 mg vs. 5 mg; 67% vs. 65% vs. 59% vs. 62% achieved response within 45 minutes defined as stable reduction of systolic blood pressure < 180 mmHg, diastolic blood pressure < 95 mmHg and relief of symptoms in patients with hypertensive emergencies; no severe side effects (Arch Intern Med 1995 Nov 13;155(20):2217)
  • mechanism of action - ACE inhibitor
  • risks - renal failure in patients with bilateral renal artery stenosis, hypotension (precipitous drop in blood pressure if volume-depleted)

Parenteral adrenergic inhibitors

labetalol (Trandate, Normodyne)

  • onset 5-10 minutes, duration 3-6 hours
  • 20 mg slow IV injection over 2 minutes, may repeat 20-80 mg every 10 minutes, do not exceed 300 mg total, alternatively 2 mg/minutes IV infusion
  • beta and alpha-1 blocker
  • use in severe hypertension
  • contraindications - bronchial asthma, bronchospasm, acute left ventricular failure, bradycardia, second or third-degree heart block, cardiogenic shock, hypoperfusion
  • side effects - postural hypotension, dizziness, fatigue, nausea, bronchoconstriction, heart block

esmolol (Brevibloc)

  • 250-500 mcg/kg/minute for 1 minute, then 50-300 mcg/kg/minute (for 4 minutes)
  • beta-1-selective adrenergic receptor blocker
  • very short duration of action (half-life 9 minutes)
  • onset < 5 minutes, duration 10-20 minutes

phentolamine

  • alpha blocker
  • used primarily for catecholamine-related hypertensive emergencies, such as cocaine intoxication, amphetamine toxicity, clonidine withdrawal, monoamine oxidase inhibitor drug interactions, pheochromocytoma
  • onset 1-2 minutes, duration 3-10 minutes
  • 5-15 mg IV bolus
  • side effects - tachycardia, orthostatic hypotension, headache, flushing

trimethaphan camsylate (Arfonad)

  • immediate onset or 1-5 minutes, duration 10-15 minutes
  • IV infusion 500 mg/500 ml D5W at 1 mg/ml (1-4 mg/min), titrate to blood pressure
  • mechanism of action - ganglionic blockade
  • drug of choice in dissecting aortic aneurysm (if propranolol cannot be used with nitroprusside)
  • contraindicated if hypertension and renal failure
  • side effects - urinary retention, paralytic ileus, tachyphylaxis, orthostatic hypotension, blurred vision, dry mouth

methyldopate - onset 30-60 minutes; 250-500 mg IV every 6 hours; drowsiness

Top  

_______________________________________________________________________________________________  

oral agents

  • nifedipine (Procardia, not extended release)
    • onset 15-30 minutes with 10-20 mg PO, duration 3-5 hours
    • 10 mg capsule SL, perforate 5-10 holes with small needle, have patient chew capsule; repeat after 30 minutes
    • mechanism of action - vasodilation
    • side effects - headache, palpitations, fluid retention, rapid uncontrolled reduction in BP may precipitate circulatory collapse if aortic stenosis
    • sublingual nifedipine should not be used for hypertensive emergencies, given unproven effectiveness and serious reported adverse effects [9 reports of transient cerebral or cardiac ischemia, 5 reports of myocardial infarction, 1 sinus arrest, 1 fetal distress after cesarean section] consistent with abrupt lowering of blood pressure (JAMA 1996 Oct 23/30;276(16):1328)
  • nicardipine (pending FDA approval) - onset 1-5 minutes, duration 3-6 hours; 5 mg/hr, increase by 2 mg/hr every 15 minutes, maximum dose 15 mg/hour; mechanism of action - vasodilation; for treatment of hypertension crisis; side effects - headache, nausea, vomiting, hypotension
  • captopril - onset 15-30 minutes; 25 mg PO repeat prn; hypotension, renal failure in bilateral renal artery stenosis
  • clonidine - onset 30-60 minutes; 0.1-0.2 mg PO, repeat every hour as required to total dose of 0.6 mg; hypotension, drowsiness, dry mouth
  • labetalol - onset 30 minutes to 2 hours; 200-400 mg PO, repeat every 2-3 hours
  • consider addition of diuretic  

       

                                                         

       2009