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Flashcards in Antianginals Deck (38)
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1
Q

Nitroglycerin and isosorbide dinitrate are all metabolized to ____

A

nitric oxide

2
Q

What class of medication is sildenafil?

A

type 5 phosphodiesterase inhibitor

3
Q

What disorder is O2 demand > O2 supply?

A

angina

4
Q

What is stable angina?

A
  • most common (atherosclerosis with cap)
  • a fixed narrowing of the coronary artery
  • onset associated with a given level of activity
  • it is predictable
    (partial occlusion to flow - with increased O2 demand this may be a problem. Smaller lumen and can not increase flow effectively)
5
Q

What is unstable angina?

A
  • onset at rest or increased physical activity (it is not predictable)
  • related to coronary atherosclerotic plaque rupture (emboli)
  • dislodged clots - lodge in coronary blood vessels
    (due to rupture of atherosclerotic plaque. Platelet accumulation and breaking off of the thrombus)
6
Q

What is vasospastic angina?

A
  • occurs at anytime, spasms of coronary artery
7
Q

What are he 2 ways that angina can be treated?

A
  • can be treated by increasing oxygen supply or decreasing oxygen demand
8
Q

What are the risk factors for angina?

A
  • smoking, dyslipidemias, diabetes, hypertension, sedentary, obesity, stress
  • family history is important - but unable to modify
9
Q

What are the 2 examples of nitrates that are used to treat angina?

A
  • nitroglycerin and isosorbide dinitrate
10
Q

Nitroglycerin can be used for both acute and prophylactic use. True or false

A

True

11
Q

Why are sublingual tablets used in an acute angina attack?

A
  • rapid onset 2-5 minutes, with a duration of 15-30 minutes
12
Q

Why are the patch or an oral tablet used to treat angina prophylactically? (to prevent pain associated with exercise)

A

they are both long acting, with the patch having a duration of 8-14 hours and the oral tablet having a duration of 6-8 hours

13
Q

Isosorbide dinitrate is used only ______

A

prophylactically (prevents pain with exercise)

14
Q

What is the mechanism of action of nitrates?

A
  • metabolized to NO (mainly in veins)
  • nitric oxide increases cGMP which mediated dilation
  • avoid giving with drugs that block cGMP breakdown
  • eg. type 5 phsophodiesterase inhibitors
  • eg. sildenafil
  • lower doses relaxes veins, and higher doses causes arteries to enlarge
  • decreases preload (venous return)
  • decreases heart size
  • may redistribute blood to ischemic areas
  • decreases pulmonary artery resistance
  • useful in pulmonary hypertension seen in COPD
15
Q

Relaxing veins in the heart does what?

A

causes venodilation -> decreasing preload (decreases venous return) -> decreases filling pressure (decreases stretch) -> decreases myocardial O2 demand and less decrease in endocardial flow (inner wall) during systole

16
Q

When does the endocardium get blood flow?

A
  • blood flow only during diastole
17
Q

When does the pericardium get blood flow?

A
  • diastole and systole
18
Q

What do nitrates prevent?

A

coronary steal - blood flowing only to the healthy areas of the heart by the B2 reflux receptors on the heart

  • by using nitrates, you are increasing the blood flow to the iscehmic acids, which is exactly where you want the blood to be flowing
  • do NOT use hydrazine in patients with angina
19
Q

Nitrates need _____ treatment intervals

A

12 hour

20
Q

What are some of the adverse effects associated with nitrates?

A
  • orthostasis
  • throbbing headache
  • reflex activation of SNS
  • salt and water retention
  • high doses may decrease BP and increase sympathetic nerve activity
    (resultant increased O2 demand and decreased perfusion pressure may be problematic)
21
Q

How do you know if the antianginals are still potent or not?

A
  • if they are potent, a slight tingling sensation should be felt under the tongue
  • crumbly tablets are likely not potent
  • they are heat and light sensitive- should carry some, but the rest should be stored in the fridge
  • there is better absorption if the sublingual mucosa is moist
22
Q

30-50% of ____ may be poor responders to nitrates

A

asians

23
Q

Why are asians poor responders to nitrates?

A
  • due to decreased mitochondrial aldehyde dehydrogenase (this is needed to convert nitrate to nitric oxide)
  • this enzyme is also needed to breakdown aldehyde associated with alcohol metabolism (a flush response to alcohol suggests a lack of ALDH2)
24
Q

What medications are used as first line treatment in chronic stable angina?

A
  • beta blockers (not for acute attacks)
  • all beta blockers are of equal benefit in angina tx - cardioselective vs non-selective)
  • recommend as initial treatment in relief of angina symptoms in stable ischemic heart disease
25
Q

What is the mechanism of action in beta blockers?

A
  • decreased oxygen demand (decreased heart rate blood pressure and contractility)
  • increase flow of blood to the ischemic region
26
Q

What is the main benefit of using beta blockers?

A
  • improved survival
  • following an MI, they are the only antianginals proven to decrease incidence of reinfarction and improve patient survive
  • if there is no previous MI, they are just as good as CCBs and nitrates as an antianginal
  • prophylactic use of antianginals to prevent the 1st MI appears to be ineffective
  • benefit in systolic heart failure
27
Q

What are the adverse effects associated with using a beta blocker?

A
  • slowing of the heart - increased EDV -> increased oxygen demand - may use with nitrates to decrease preload and EDV
  • not for vasospastic angina- may worsen
28
Q

Dihydropyridines decrease the ______ and may also decrease ______

A

afterload

coronary vascular tone

29
Q

What effect do dihydropyridines have on cardiac suppression?

A

very little effect (may cause reflex increase in cardiac B-receptor activity)

30
Q

How does verapamil work as an antianginal?

A
  • decreases oxygen demand (negative inotrope, chronotrope, lowers blood pressure)
  • poor vascular dilator
31
Q

How does diltiazem work as an antianginal?

A
  • decreases oxygen demand (negative inotrope, negative chronotrope, lowers blood pressure)
  • effective coronary arterial dilator (less peripheral)
32
Q

What are the benefits of using calcium channel blockers?

A
  • decrease symptoms, increase exercise tolerance/time
  • if a beta blockers alone is ineffective or contraindicated
    (substitute with a CCB or combine with a CCB)
  • effective for vasospastic angina - dihydropyridines
33
Q

What are the adverse effects associated with using calcium channel blockers?

A
  • serious cardiac suppression (verapamil and B-blocker - possible heart block)
  • constipation, ankle deem
  • sympathetic reflexes (nifedipine vs verapamil)
  • dizziness, hypotension, headache, flushing
34
Q

Amlodipine causes ____ tachycardia compared to verapamil

A

less

35
Q

What is typically used as a treatment for angina of effort?

A
  • ASA or clopridogrel
  • nitrates or Beta adrenergic receptor blockers if there are problems with the first 2 (increases time of onset of angina and ST depression during exercise treadmill test)
  • get angina at same level of oxygen demand
  • long term: start with a beta blocker (prevents reinfarction and improves survival)
36
Q

What are the “go to drugs: for treating both hypertension and angina?

A
  • beta blockers or long acting calcium channel blockers (dihydropyridine)
37
Q

What medications should be used to treat unstable angina?

A
  • ASA, clopridogrel
  • IV heparin added to ASA
  • oxygen
  • nitroglycerin, give IV if pain persists after 3 tablets
  • morphine
  • oral beta blockers given IV
  • statins
  • in this case, giving a beta blocker will decrease ischemic episodes but not mortality
38
Q

What should be given as therapy for vasospastic angina?

A
  • calcium channel blockers and nitrate
  • avoid giving…
  • – beta adrenergic receptor blockers
  • – ASA, decreases prostacyclin which is a vasodilator
  • sumatriptan (used in migraines, may constrict coronary arteries)