Vasodilators PPT part 2 Flashcards
ACE I are free of many SE’s associated with other antihypertensive drugs including:
- depression
- insomnia
- sexual dysfunction
AE’s such as HF, bronchospasm, bradycardia, and exacerbation of PVD are not seen with:
ACE inhibitors
Are metabolic changes induced by diuretic therapy (hypokalemia, hyponatremia, and hyperglycemia) observed in ACE I?
No!
Do ACE inhibitors see the same rebound htn as clonidine users?
nope!
ACE inhibitors have been established as first line therapy for pts with: (3)
- CHF
- Mitral regurgitation
- Systemic HTN
ACE inhibitors are more effective and possibly safer than other antihypertensive drugs in the tx of
HTN in diabetics
there is evidence that ACE I delay the progression of
diabetic renal disease
ACE I have been shown to provide survival benefit to pts who (2 types):
- have suffered a MI
2. with HF
Angiotensin II binds to a specific cell membrane receptor:
This Receptor ultimately leads to:
- AT1
- increased release of Ca+ from SR to produce vasoconstriction
Decreased generation of angiotensin II due to the administration of an ACE inhibitor results in
-reduced vasoconstrictive
effects
-decreased plasma concentrations of aldosterone resulting in less sodium and water retention
ACE I also block the breakdown of
bradykinin
Bradykinin is what? what does it do?
- an endogenous vasodilator
- contributes to the antihypertensive effects of ACE I
How are ACE I like statins?
they reduce LDL activation thus reducing plasma concentrations of LDL
What ACE I is a PRODrug?
Enalapril
-the prodrug of the active ACE I, enalaprilat
Conversion of enalapril may be altered in patients with?
Hepatic dysfuntion
Captopril and lisinopril are not:
Prodrugs
The major difference among various clinically used ACE I is in:
duration of action
Name the most common SE of ACE I:
- cough
- Rhinorrhea
- Upper Respiratory congestion
- allergic-like symptoms
What patient type more frequently experiences the cough associated with ACE I?
Women
If RD develops, prompt tx of what is advised?
Epi (0.3-0.5mL of a 1:1,000 dilution) Subcutaneously
A potentially life-threatening complication of tx with ACE I is?
Angioedema
*an EMERGENCY!
ACE Inhibitors may decrease what in patients being treated with ACE I:
GFR
Who would you use ACE I with caution in?
What patients are not recommended for tx with ACE I?
- caution in pre-existing renal dysfunction
- not rec. for patients with renal artery stenosis
The risk of hyperkalemia is greatest in patient’s with what RF’s?
What causes the hyperkalemia with ACE I?
Recognized RF - CHF with renal insufficiency
-Hyperkalemia is possible d/t decreased production of ALDOSTERONE
- Due to adverse effects to the circulatory system during anesthesia in pts chronically treated with ACE I, what is the recommended discontinuation timeline?
- What happens with GA? 3. How would you tx this?
1-D/C 12-24hrs before anesthesia and surgery.
2- exaggerated HYPOtension
3- responsive to cystalloid fluid infusion and/or admin of a catecholamine or vasopressin
What did Dr. Hammon say was the issue with stopping ACE I 12-24h before surgery?
it’s still likely in the pt’s system
ACE I may increase sensitivity to:
insulin (and hypoglycemia)
*concern w/DM
Is there evidence that the incidence of hypoglycemia is great in diabetics being treated with ACE I for control of HTN?
no
Name the only IV ACE I:
and a few notes about it
enalaprilat
- there’s little published to guide its use in this setting. Not used as a gtt. Dosing rec’s are for intermittent injection.
- has a less predictable onset and DOA as well as antihypertensive action than short-acting direct vasodilators
Angiotensin II Receptor inhibitors produce antihypertensive effects by blocking the:
vasoconstrictive actions of angiotensin II w/o affecting ACE activity
Common Angiotensin II R-inhibitors are:
- candesartan
- losartan
- valdesartan
*All have relatively long DOA; once/twice daily dosing
Name the IV angiotensin II R-inhibitor agent
there is no iv agent available
Angiotensin II R-inhibitors have similar SE profile to?
What do they not do?
- ACE I
- the do not inhibit breakdown of bradykinin
–> (one of the benefits of ACE I that make it generally a preferred first line therapy)
A major difference b/w ACE and ARBs is:
ARBs do not cause cough
What percentage of pts tx with ACE I may not tolerate it d/t cough?
more than 10%
D/t hypotension following induction/anesthesia in pts treated with ARBs, some recommend these drugs be discontinued:
on the day before surgery
These are historically the vasodilators most widely used by anesthesia providers
Sodium nitroprusside (SNP) and IV nitroglycerin
*“nitrodilators”
SNP and Nitroglycerin work through the generation of:
Which then augments ____ in ____ ____ ____, both arteries and veins, leading to _____.
- NO
- cyclic cGMP in vascular smooth muscle,
- vasodilation
Nitroprusside (SNP) is a
direct acting, Nonselective peripheral vasodilator that causes relaxation of arterial and venous vascular sm
SNP lacks significant effects on -
nonvascular smooth muscle and on cardiac muscle
- SNP onset of action is:
- equipotent on:
- its duration is:
- almost immediate
- arteries and veins,
- transient- requiring continuous IV administration to maintain a therapeutic effect
SNP necessitates careful titration of dosage as provided by continuous infusion devices and frequent monitoring of systemic blood pressure, often by intraarterial monitoring due to it’s:
extreme potency
SNP interacts with oxyhemoglobin, dissociating immediately and forming
methemoglobin while releasing cyanide and NO
Once released, NO activates the enzyme :
Resulting in increased:
- guanylate cyclase (present in vascular smooth muscle)
- intracellular concentrations of cGMP
cGMP inhibits
calcium entry into vascular smooth muscle cells and may increase calcium uptake by the smooth endoplasmic reticulum to produce vasodilation.
What is the active mediator responsible for the direct vasodilating effect of SNP
NO
SNP spontaneously generates this product, thus functioning as a prodrug
NO
*(in contrast to Nitroglycerin, -organic nitrate-which requires trio-containing compound to generate NO)
Metabolism of SNP begins with the transfer of an electron from the iron of oxyhemoglobin to SNP, yielding
methemoglobin and an unstable SNP radical