Updated: 5/8/2021

Antihypertensive Therapy

0%
Topic
Review Topic
0
0
N/A
N/A
Questions
10
0
0
0%
0%
Evidence
16
0
0
Topic
https://upload.medbullets.com/topic/108066/images/htn.jpg
Snapshot
  • A 44-year-old man presents to his primary care physician for an annual examination. He currently does not have any acute complaints. He has been attempting to increase the number of fruits and vegetables in his diet and has lost approximately 15 pounds over 6 months. His medical history is significant for type II diabetes mellitus and he is currently taking metformin. Physical examination is remarkable for a blood pressure of 155/103 mmHg and mildly decreased vibration and proprioception sense in his lower extremities. He returns to the clinic for two consecutive days to measure his blood pressure, which is 152/100 mmHg and 158/107 mmHg. He is started on lisinopril.
Introduction
  • Antihypertensive medications are used to manage hypertension in patients where conservative measures are ineffective
    •  there are four commonly used antihypertensive medications 
      • diuretics
        • thiazides
        • potassium-sparing diuretics
      • sympatholytics
        • β-blockers
        • α-blockers
      • vasodilators
        • calcium channel blockers 
        • hydralazine
        • minoxidil
      • renin-angiotensin-aldosterone inhibitors
        • angiotensin-converting enzyme (ACE) inhibitors
        • angiotensin receptor blockers (ARBs)
Diuretics
  • Medications
    • thiazides
      • mechanism of action
        • inhibits the NaCl transporter in the distal tubule
        • vasodilation (mechanism is unclear)
    • potassium-sparing diuretics
      • mechanism of action
        • promotes Na+ excretion in the distal nephron
Sympatholytics
  • Medications
    • β-blockers 
      • mechanism
        • decreases heart rate, which in turn, decreases cardiac output
        • decreases renin release, which in turn, decreases total peripheral resistance
      • notes
        • can result in bronchospasm, impotence, and hyperglycemia
      • e.g., metoprolol
    • α-agonists
      • mechanism
        • central α2-agonist
          • decreases the sympathetic outflow to blood vessels, heart, and kidneys by activating presynaptic
            α2-adrenoreceptors
            • e.g., methyldopa and clonidine
    • α-blockers
      • mechanism
        • α
          1
          -blockers
          • blood vessel smooth muscle relaxation
            • e.g., prazosin
Vasodilators
  • Medications
    • hydralazine
      • mechanism
        • increases cGMP to cause direct vascular smooth muscle relaxation
      • note
        • this causes a reflex tachycardia; therefore, β-blockers are often given together
    • minoxidil
      • mechanism
        • direct arteriolar smooth muscle relaxation
    • calcium channel blockers
      • mechanism
        • decreases cardiac and vascular calcium influx, resulting in a decreased cardiac output and total vascular resistance
Renin-Angiotensin-Aldosterone Inhibitors
  • Medications 
    • angiotensin-converting enzyme (ACE) inhibitors 
      • mechanism
        • inhibits ACE, which in turn, decreases circulating angiotensin II (AT-II)
          • recall that AT-II causes
            • vascular vasoconstriction
            • increased aldosterone secretion from the adrenal gland (zona glomerulosa)
      • notes
        • decreases mortality in patients with
          • acute myocardial infarction 
          • heart failure with decreased ejection fraction
        • can result in a cough 
        • beneficial for patients with diabetes
    • angiotensin receptor blockers (ARBs) 
      • mechanism
        • directly blocks the AG-II receptor
      • notes
        • beneficial for patients with diabetes
Antihypertensives in Pregnancy
  • Medication options used to manage hypertension in pregnancy include
    • hydralazine 
    • labetalol
    • methyldopa
    • nifedipine
Antihypertensives in Hypertensive Emergencies
  • Nitroprusside
    • mechanism
      • arteriole and venous dilation via cGMP
    • notes
      • is metabolized into cyanide, which can potentially lead to cyanide poisoning
  • Fenoldopam
    • mechanism
      • a peripheral dopamine-1 receptor agonist
    • notes
      • maintains renal perfusion while the blood pressure is being decreased
        • therefore, it is beneficial in patients with renal impairment
  • Nicardipine and clevidipine
    • mechanism
      • decreases cardiac and vascular calcium influx
  • Labetalol
    • mechanism
      • α- and β-blocker
 
Antihypertensive Medications That Address Comorbid Conditions
 
Individualizing Antihypertensive Therapy
Condition Antihypertensive Medication
Benign prostatic hyperplasia
  • α-blockers 
Essential tremor
  • β-blocker
Hyperthyroidism
  • β-blocker
Migraine
  • β-blocker
  • Calcium channel blocker
Osteoporosis
  • Thiazide diuretics
Raynaud phenomenon
  • Dihydropyridine calcium channel blocker
 
  • renin-angiotensin-aldosterone inhibitors

Please rate topic.

Average 4.8 of 9 Ratings

Questions (10)
Evidence (16)
VIDEOS & PODCASTS (1)
EXPERT COMMENTS (9)
Private Note