MISCELLANEOUS ANTIHYPERTENSIVES

See also Nitroprusside

I. Angiotensin II receptor antagonists ("ARB's")

  1. Block binding of angiotensin II to the ATII type 1 receptor
  2. Can cause angioedema (very rare) and hyperkalemia
  3. Contraindicated in 2nd or 3rd trimester of pregnancy
  4. Associated with decreased incidence of Diabetes Mellitus and better clinical outcomes than Beta-Blockers in the LIFE Study
  5. Also of benefit in patients with Congestive Heart Failure--click on link for details
  6. Ditto for Diabetic Nephropathy
  7. Specific agents:
    1. Losartan* (Cozaar) 25-100mg divided QD-BID
    2. Valsartan* (Diovan) 80-320mg QD
    3. Irbesartan (Avapro) 150-300mg QD
    4. Candesartan (Atacand) 8-32mg QD
    5. Telmisartan (Micardis) 40-80mg QD
    6. Eprosartan (Teveten) 400-800mg divided QD-BID
    7. Olmesartan (Benicar) 20-40mg QD

II. Direct vasodilators

  1. Can cause HA, fluid retention, tachycardia
  2. Specific agents:
    1. Hydralazine* 40-200mg divided BID-QID (can cause headache, vomiting, and drug-induced lupus); 10-20mg IV or 10-50mg IM
    2. Minoxidil 2.5-40mg divided QD-BID (can cause hirsutism)

III. Alpha-blockers

  1. Can cause postural hypotension, esp with first dose; also can cause anticholinergic effects and priapism
  2. Concern over assocation w/CAD & CVA--see results of the ALLHAT study (click link for details)
  3. Specific agents
    1. Doxazosin (Cardura) 1-16mg QD
    2. Terazosin (Hytrin) 1-20mg QD
    3. Prazosin (Minipress) 1-20mg divided BID-TID--ass'd with more first-dose hypotension than the others
    4. Alpha-blockers designed specifically to treat Benign Prostatic Hyperplasia
      1. Tamsulosin (Flomax) 0.4-0.8mg QD
      2. Alfuzosin (Uroxatral) 10mg QD-Contraindicated in pts with mod-severe hepatic impairment (Med. Lett. 46:2, 2004)

IV. Centrally acting agents (alpha-adrenergic agonists)

  1. Can cause sedation, depression, dry mouth, bradycardia, withdrawal HTN, lupus-like syndromes, and hemolytic anemia
  2. Can cause paradoxical HTN when used in conjunction w/beta-blockers
  3. Specific agents
    1. Clonidine* (PO 0.1-0.6 mg/d divided BID-TID; transdermal 0.1-0.3mg/d, one patch weekly)--may potentiate anesthetic agents
    2. Guanabenz 4-64 mg/d divided BID
    3. Guanfacine 1-3mg QD
    4. Methyldopa* 250-2000mg divided BID (can cause hepatic dysfunction and "autoimmune" reactions; may increase serum lithium levels)

V. Peripheral adrenergic agents

  1. Can cause postural hypotension and diarrhea
  2. Specific agents
    1. Guanadrel 10-75mg divided BID
    2. Guanethidine 10-50mg QD
    3. Reserpine 0.05-0.1 mg QD (can worsen depression and PUD, causes sedation and nasal congestion too)

VI. Fenoldopam (Med. Lett. 40:57, 1998--AFP)

  1. A peripheral dopamine-1 agonist for parenteral tx of severe HTN
  2. Induces arteriolar vasodilation; increases renal blood flow
  3. Also has direct diuretic and natriuretic effect on renal tubular cells
  4. Not much tolerance or rebound HTN after d/c
  5. Has been used to tx CHF; reduces afterload and increases cardiac output but didn't decrease PCWP
  6. Can cause side f/x due to vasodilation: hypotension, flushing, dizziness, HA, tachycardia; also nausea & hypokalemia
  7. Can increase intraocular pressure
  8. Don't use in combination w/beta-blockers b/c the latter could inhibit reflex tachycardia and result in severe hypotension
  9. Dosing: 0.1-1.6 ug/kg/min (start low, titrate up 0.05-0.1ug/kg/min Q15min)

(Sources include the 6th Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure--Arch. Int. Med 157:2413, 1997)

*--Available in combination with diuretics as of 1999