anti HTN drugs (part 1)

Question 1

antihypertensives:

1. hydralazine -aka
2. action:
3. metabolism via:
4. side effects
5. uses:
6. use cautiously in:

Answer 1

1. apresoline
2. arteriole dilation by relaxation of smooth muscle (arteriole > venous)
3. acetyltion (faster in rapid acetylators)
4. increased heart rate (reflex tachycardia, especially if give to tachycardic persons) d/t direct cardiac action
5. in HTN to decrease afterload in CHF persons
6. CAD patients

Question 2

antihypertensives:
Hydralazine:
1. dose:
2. onset:
3. duration:

Answer 2

1. 2.5-40 mg
2. 5-20 min
3. 2-4 hours iv

Question 3

antihypertensives:

1. ace inhibitior: brand name?
2. action:
3. what does this prevent?
4. what secondary hormone is prevented by this drug?
5. what does competitively inhibit mean?

Answer 3

1. enelapril/ vasotec
2. competetively inhibit the conversion of angiotensin I to angiotensin II by enyme ACE (a peptidiy-dipeptidase)
3. prevents angiotensin II mediated stimulation of SNS and vasoconstriction
4. blocks aldosterone release by inhibiting angiotensin II
5. it can be over-ridden if demand is higher

Question 4

antihypertensives:
ace inhibitiors:
1. what are they the first line drug in?
2. what patient population are these drugs safer than other antihypertensives in? why?
3. what do they improve as far as heart issues?

Answer 4

1. first line drug in patient with CHF, HTN and mitral regurg
2. safer than other antiHTN in diabetics because they delay the progression of diabetic renal disease
3. improve left ventricular hypertrophy in CHF patients

Question 5

antihypertensives:
ACE inhibitors: airway side effects:
1. mild ; cause?
2. severe; cause?

Answer 5

1. cough, upper resp congestion, allergy like symptoms (d/t inhibition of peptidyl-dipetidase)
2. angioedema (d/t drug induced inhibition of metabolism of bradykinin).

Question 6

antihypertensives: 
ACE inhibitiors: renal:
1. what is the renal side effect?
2. what patients should these drugs be avoided in?
3. why?

Answer 6

1. proteinuria in about 1% of patients especially in patients with preexisting renal disease.
2. renal artery stenosis
3. renal perfusion in renal artery stenosis is highly dependent on angiotensin II

Question 7

antihypertensives:
ACE inhibitiors: anesthesia implications:
1. what is the new general consensus of taking ACE inhibitors before surgery?
2. what do you need to avoid with blood pressure intra op? why?
3. for what reasons patients are taking ACEs will decreases in blood pressure be a problem?
4. why dont some anesthetists like the effects of ACE inhibitors intra op; what might these patients need?

Answer 7

1. take your am ACE as well or when was last dose (usually p.m.)
2. avoid fluctuations in BP; may need higher perfusion pressures intraop (for brain)
3. patients may have CAD, CHF as well as HTN
   4 blood pressure hard to control, may need antihypertensives or fluids

Question 8

recap questions:

1. how does clonidine work?
2. what are other uses for clonidine besides antiHTN?
3. how does hydralazine work?
4. how do ACE inhibitors work?
5. what are 4 anesthesia implications of ACE inhibitors?

Answer 8

1.

Question 9

what are the 5 classes of drugs used to manage hypertension

Answer 9

1. sympatholytics (alpha and beta blockers)
2. ace inhibitors/ ARBS
3. calcium channel blockeers
4. diuretics
5. vasodilators

Question 10

antihypertensives:
Prazosin: aka?
1. action?
2. uses?
3. first group that it is safe for, why?
4. second group that it is safe for, why?

Answer 10

Minipress
1. selective alpha 1 blockade; vasodilation of resistance (arterial vessels) and capacitance (venous vessels) (aka decreases pre and after load).
2. useful preop for pheochromocytoma patients, good for CHF patients (decreases preload and afterload)
3. safe for asthmatics d/t only alpha 1 bolckade
4. renal patinents d/t metabolized solely in liver
4.

Question 11

antihypertensives:

clonidine: aka?
1. drug class:
2. what is the ratio?
3. mechanism of action; where exactly (in the body) does it work?
4. how is this accmplished on a cellular level and what desirable s/e might this cause?

Answer 11

catapress

1. centrally acting selective alpha 2 agonist, very,very slight A1
2. alpha 2=220: alpha 1=1 (220:1 ratio)
3. works at medullary vasomotor center; decreases CNS sympathetic output which decreases BP
4. modifies K+ channel; may explain decrease in MAC

Question 12

antihypertensives: 
Clonidine: 
1. Other uses (besides hypertension)
2. where is it administered?
3. what is its action?
4. what are pros to this approach
5. what are potential cons: s/e's

Answer 12

1. analgesia
2. given via subarachnoid (spinal) or epidural
3. activates postsynaptic A2 receptors in substantia gelatinosa (II,III & ?V)
4. lacks the side effects of opiates (pruritis, N/V or respiratory depression)
5. can cause hypotension

Question 13

antihypertensives:
clonidine:
1. other uses in anesthesia:
2. s/e with pregnancy?
3. diagnostic uses: what disease is this used to dx?
4. other uses (4 uses 1 common, 3 alternative)

Answer 13

1. anesthesia:
   a) 75-100 mcg added to LA prolongs SAB, brachial plexus block
   b) po clonidine given 1 hour prior can prolong SAB, but may cause hypotension
2. in pregnant: may cause fetal bradycardia (dangeroso!!)
3. diagnosis of pheochromocytoma Clonidine Suppression Test:(will reduce catecholamines in normal patients, but not in pheochromocytoma patients).
4. a) opiate withdrawl (replaces opiate mediated inhibition of CNS with a2 mediated inhibition)
   b) may do same for nicotiene withdrawl
   c) shivering (by inhibiting thermoregulatory controls)
   d) preanesthetic (may decrease analgesia needs-though not commonly used for this).