L14 CVS

Question 1

GTN

Glyceryl trinitrate

Answer 1

GTN converted to NO, stimulates guanylate cyclase, increase CGMP-> vasodilation
dilates veins- decrease preload
dilates arterioles-decrease afterload
dilates coronary collateral vessels

Question 2

GTN absorption

Answer 2

non ionic, very high lipid solubility-> absorbed rapidly
very potent
venous drainage from mouth to SVC
avoids hepatic first pass metabolism

Question 3

Alpha 1 adrenoceptor blockers/antagonists

mechanism

Answer 3

1. Inhibit vascular alpha adrenoceptors
2. Inhibit NA-mediated mechanisms
3. Decrease TPR
4. Decrease BP

Question 4

eg Alpha 1 adrenoceptor blockers/antagonists

Answer 4

zosin

prazosin

Question 5

Alpha 1 adrenoceptor blockers/antagonists

side effects

Answer 5

1st dose hypotension
»  within 90 min of initial dose; ≈50% patients
❖  initial reflex tachycardia 
❖  postural hypotension
»  problem in elderly patients 
❖  nasal congestion

Question 6

ACE Inhibitors mechanism

Answer 6

1. inhibit ACE
2. Decrease circulating Ang 2, increase bradykinin
3. Less vasoconstriction, more vasodilation
4. Decrease TPR
5. Decrease BP

Question 7

eg ACE Inhibitors

Answer 7

pril
Captopril
Enalapril

Question 8

ACE Inhibitors side effects

Answer 8

1st dose hypotension
hyperkalaemia too much K
decrease Ang II -> decrease in aldosterone K+ retention (usually only problem for patients on K+-sparing diuretics)
acute renal failure (reversible)

usually in patients with renal artery stenosis
dry cough (increase bradykinin as ACE = kininase II)
ACEIs with sulfhydryl group (e.g. captopril)
– altered/loss of taste (reversible)
– 
rash (reversible)

Question 9

Eg Angiotensin AT1 receptor antagonists

Answer 9

sartan

Losartan

Question 10

Angiotensin AT1 receptor antagonists side effects

Answer 10

• 1st dose hypotension
• Hyperkalaemia
• Renal problems
• But no dry cough, no increase in bradykinin

Question 11

L-type Ca channel blockers mechanism

Answer 11

1. Inhibit L-type Ca channels
2. Decrease Ca entry in vascular smooth muscle, low intracellular ca
3. Decrease vascular contractile tone
4. Decrease TPR, especially due to arteriolar dilatation
5. Decrease BP

Question 12

Eg L-type Ca channel blockers

Answer 12

Dihydropyridines DHPs
pine
Nifedipine, felodipine, amlodipine

Question 13

Adverse effects of Eg L-type Ca channel blockers

Answer 13

reflex tachycardia, palpitations, nausea, flushing, headache