by mtoom


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Name 6 important classes of drugs that are used in Hypertension
  • Thiazides
  • ACE-inhibitors
  • ARBs
  • Calcium channel bockers
  • α-blockers
  • β-blockers
What are the 2 mechanisms of Thiazides in lowering blood pressure?
  • Natriuresis/Diuresis
  • Vasodilation
    (Anti-hypertensive effectiveness not proportional to diuretic effect)
Should Thiazides be considered for HTN? Name the prototype thiazide.
Yes, they are 1st line agents for HTN.

Prototype: Hydrochlorothiazide 
How do ACE-inhibitors work physiologically?
Inhibit conversion of ATI to ATII by Angiotensin-converting enzyme (ACE)
What are the effects of ATII (6)?
  • systemic vasoconstriction

  • constriction of efferent arteriole → ↑GFR, ↑Hydrostatic pressures
     
  • Na+ reabsorption at Proximal Tubule (PT)
     
  • aldosterone release → ↑Na+ reabsorption at TAL, DT, CCD

  • systemic release of ADH

  • renal sympathetic activity
Describe how 4 effects of ACE-inhibitors that are relevant for reducing blood pressure.

(Probably most of the effects of inhibiting ATII are relevant.)

ACE Inhibitors will:
  • ↓ systemic vasoconstriction
  • ↓ aldosterone release
  • ↓ NaCl reabsorption
  • ↑ vasodilation (due to bradykinin)
What are 2 important effects of increased bradykinin?
  • Cough
  • Vasodilation (ACE normally blocks activation of bradykinin, a vasodilator)
What are the 1 major systemic effect of ACE inhibitors and 1 major effect in kidney?
  • systemic: ↓systemic vascular resistance

  • Kidney: ↓intraglomerular pressure (beneficial)
What are 3 side effects due to ↑bradykinin?

What is 1 side effect due to ↓aldosterone?
Bradykinin
  • Cough
  • Angioedema (due to vasodilation)
  • Renal dysfunction
Aldosterone
  • Hyperkalemia (due to not exchanging K+ at CCD)
Name 1 prototype for an ACE-inhibitor
Ramipril
Describe the mechanism of action of ARBs. Give 1 prototype of an ARB.
MOA: Angiotensin receptor blocker: blocks AT1 receptor (this is one of the receptors for ATII)

Prototype: Losartan
What is the major advantage of ARBs over ACE-inhibitors?
No cough (with ARBs)

Switch patients who are irritated by the cough (due to the ACE inhibitor), because much benefit is preserved with ARBs.
What is the mechanism of Ca2+-channel blockers?
Block influx of Ca2+ through Calcium channels in heart
What are the 2 main groups of Ca2+-channel blockers?
  • Dihydropyridines
    ("-pine") drugs 
  • Non-dihydropyridines
Describe the 3 main effects of Ca2+-channel blockers?
  • ↓ HR
  • ↓ Contractility
  • ↑ Vasodilation
What is the different between the dihydropyridines and the non-dihydropyridines?
Dihydropyridines
  • Vascular > Heart
Non-dihydropyridines
  • Heart > Vascular
Name 3 Dihydropyridines
  • Amlodipine
  • Nifedipine
  • Felodipine

Vessels > Heart
Name 2 Non-dihydropyridines
  • Diltiazem
  • Verapimil

Heart > Vessels
Give 1 example of an α-blocker. Describe mechanism. What are the 2 systemic effects? What is the 1 classic side effect?
Prazosin (blocks alpha-receptors, which mediate vasoconstriction)
  • Effects: Vasodilation (arteries and veins) 

Classic side effect: Orthostatic hypertension
Name 2 examples of β-blockers. Describe mechanism. Name 2 effects. What are 2 contraindications to β-blockers.
Metoprolol, propranolol (block beta-receptors)
  • Reduce contractility
  • Reduce HR

2 contraindications
  • Asthma (β-blockers cause bronchoconstriction)
  • Fatigue
Name 3 classes of β-blockers
  • Cardioselective
  • Non-cardioselective
  • Partial agonists
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