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Pharmacology Test #3 > 11.12 pharm of angina pectoris > Flashcards

11.12 pharm of angina pectoris Flashcards

1
Q

what is Angina Pectoris?

A

Chronic disease, intermittent attacks of chest pain, radiate through chest, shoulder & arm

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2
Q

what are the four types of angina?

A

A: typical (stable, effort) angina (major type)
B. Variant (Prinzmetal’s) angina:
- ↓ O2 supply - unchanged demand - ie. at rest, coronary spasm (PGs?)
C. Unstable angina: (most dangerous)
- ↓ O2 supply, plaque, platelets, clot
D. Microvascular angina (Syndrome X):
- atherosclerosis in small coronary a.

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3
Q

Typical (Stable, Effort) angina:

A
  • ↑ O2 demand - fixed supply
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4
Q

Variant (Prinzmetal’s) angina:

A
  • ↓ O2 supply - unchanged demand - ie. at rest, coronary spasm (PGs?)
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5
Q

Unstable angina:

A
  • ↓ O2 supply, plaque, platelets, clot
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6
Q

Microvascular angina (Syndrome X):

A
  • atherosclerosis in small coronary a.
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7
Q

what are the main mechanisms to treat angina (basic)

A

-angina is a supply vs demand problem, so either increase the oxygen supply or decrease the oxygen demand

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8
Q

The primary determinants of myocardial O2 supply:

A

a. Coronary blood flow (major determinant)
b. O2 content of the blood
c. O2 extraction by the myocardium

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9
Q

The primary determinants of myocardial O2 consumption:

A

a. Ventricular systolic pressure (afterload)
b. Heart size (preload)
c. Heart rate
d. Myocardial contractility

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10
Q

Improving supply/demand ratio:

A

a. Relaxation of resistance vessels (small arteries and arterioles) ↓TPR → ↓BP → ↓Afterload, ↓O2 demand
(Nitrates, calcium channel blockers and beta-blockers)
b. Relaxation of capacitance vessels (veins and venules) ↓Venous return, ↓heart size, ↓Preload, ↓O2 demand (Nitrates)
c. Blockade or attenuation of sympathetic influence on the heart ↓Contactility, ↓HR, ↓O2 demand
(Beta-blockers)
d. Coronary vessel dilation
- Important mechanism for relieving vasospastic angina - ↑O2 supply
(Nitrates)

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11
Q

Relaxation of resistance vessels (small arteries and arterioles) ↓TPR → ↓BP → ↓Afterload, ↓O2 demand

A

Nitrates, calcium channel blockers and beta-blockers)

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12
Q

Relaxation of capacitance vessels (veins and venules) ↓Venous return, ↓heart size, ↓Preload, ↓O2 demand

A

nitrates

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13
Q

Blockade or attenuation of sympathetic influence on the heart ↓Contactility, ↓HR, ↓O2 demand

A

beta-blockers

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14
Q

Coronary vessel dilation

- Important mechanism for relieving vasospastic angina - ↑O2 supply

A

nitrates

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15
Q

nitrates mechanism of action:

A
  • Direct smooth m. relaxation
  • High specificity vascular sm
  • Vasodilation: veins > arteries
  • ↓Preload > ↓Afterload
    a. Formation of NO in endothelial cells involving sulfhydral (SH) groups
    b. Interaction between NO and thiols in smooth mus. to form nitrosothiols
    c. Nitrosothiol activates guanylate cyclase and increased formation of cGMP
    this leads to vasodilation
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16
Q

continual use of nitrates leads to ….

A

Tolerance (formation of disulfide bonds)
oxidation of SH groups and formation of disulfide bonds - develops fast and recovers fast ie. “Monday syndrome or Head”
-So individuals need abstinence periods

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17
Q

Nitrates and Nitrites MOA

A
  • Formation of Nitric oxide (NO) → activation of guanylate cyclase
  • ↑ Ca++ uptake SR, dephosphorylation of myosin-LC
    Tolerance: frequency / dose dependence (absence periods)
    Absorption and disposition: well absorbed, first-pass metabolism with oral administration (10-20%)
18
Q

adverse actions of nitrates and nitrites

A

Adverse actions: headache, flushing, hypotension, reflex tachycardia, possible circulatory collapse CI: PDE5 inhibitors (ie. Viagra)

19
Q

when are nitrates and nitrites contraindicated?

A

with PDE5 inhibitors (ic Viagra)

20
Q

Viagra

Sildenafil

A
  • phosphodiesterase type 5 inhibitor
  • ↑NO release
  • leads to ↑cGMP
  • initially developed for angina
  • CI with nitrates, alpha-blockers
21
Q

Nitroglycerin - Routes of administration

A
  1. Sublingual tablet (for an acute attack)
    • Avoids first-pass effect
    • Onset: 30 sec, Duration: 30 min
  2. Buccal tablet
    • Tablet placed in buccal cavity
    • Adheres to mouth’s mucosal surface, NG released for 3-6 hrs
  3. Oral
    • Translingual spray – Duration 30 min
    • Oral tablet – Duration 6 hrs, subject to first-pass effect
  4. Topical
    a) ointment (paste)
    • Duration: 3-4 hrs, used in acute care setting
    • Inconvenient, messy, largely replaced by patch
    b) Transdermal system (patch)
    • Delivers nitroglycerin over 24 hr period
    • Avoid continuous use to prevent tolerance (remove at night)
22
Q

Sublingual tablet (Nitroglycerin)

A

Avoids first-pass effect

• Onset: 30 sec, Duration: 30 min

23
Q

Buccal tablet (nitroglycerin)

A
  • Tablet placed in buccal cavity

* Adheres to mouth’s mucosal surface, NG released for 3-6 hrs

24
Q

Oral (nitroglycerin)

A
  • Translingual spray – Duration 30 min

* Oral tablet – Duration 6 hrs, subject to first-pass effect

25
Q

Topical nitroglycerin

A

a) ointment (paste)
• Duration: 3-4 hrs, used in acute care setting
• Inconvenient, messy, largely replaced by patch
b) Transdermal system (patch)
• Delivers nitroglycerin over 24 hr period
• Avoid continuous use to prevent tolerance (remove at night)

26
Q

acute onset/attack angina use which nitroglycerin route of admin?

A

-sublingual tablet or translingual spray

27
Q

Isosorbide dinitrate [ISDN] – converted to ISMN c. Isosorbide mononitrate [ISMN]

A

• Active metabolite of ISDN
• Not subject to first-pass metabolism
• Greater bioavailability (100%)
• Clinical efficacy not greater than ISDN
Both forms have: 30 min onset, 6 hr duration

28
Q

Calcium Channel Blockers and use for angina

A
  • frontline class, oral and generally well absorbed
  • bind to L-type calcium channels in cardiac and vascular smooth muscle
  • inhibition of calcium influx into cardiac and arterial smooth muscle cells
  • minimal effect on venous capacitance vessels.
  • dilate arterioles →↓TPR →↓ BP (less verapamil, more nifedipine), ↓ afterload
  • negative inotropic action on heart (more verapamil, less nifedipine), →↓ oxygen demand
  • T1⁄2: most 2-5 hrs, bepridil 42 hrs, amlodipine 30-50- hrs
  • CHRONIC TXT
29
Q

Nifedipine: (DHP)

A
  • mainly arteriole vasodilation, little cardiac effect - reflex tachycardia, flushing, peripheral edema
30
Q

Verapamil:

A
  • significant cardiac depression, constipation
  • caution in digitalized patients (↑ digoxin levels)
  • incr renal blood flow (CCBs tend to incr renal blood flow)
31
Q

Diltiazem:

A
  • similar to Verapamil / Nifedipine (less) - actions on cardiac and vascular beds
  • INCR. RENAL BLOOD FLOW
32
Q

examples of Non-dihydropyridines (non-DHPs):

A

verapamil, diltiazem

33
Q

examples of Dihydropyridines (DHPs):

A

Nifedipine, or anything with [-dipine]

34
Q

Calcium-Blockers: Adverse effects

A
  • constipation (more likely with non-DHPs)
  • non-DHPs: cardiac depression, bradycardia, AV block
  • non-DHPs are contraindicated with beta-blockers
  • mostly DHPs: hypotension, reflex tachycardia, flushing, headache, edema
  • hypotension (more likely with DHPs)
  • gingival hyperplasia (nifedipine, 10%)
  • CHF non-DHPs contraindicated, DHPs not recommended - CYP3A4 inhibitors: grapefruit, verapamil, diltiazem
  • CYP3A4 substrates: amlodipine, verapamil
35
Q

Drug Choices in Angina: Effort angina

A

nitrates, calcium-blockers, beta-blockers, aspirin

36
Q

Drug Choices in Angina: variant angina:

A

nitrates, ccbs

37
Q

drug choices for unstable angina

A

nitrates, calcium-blockers, beta-blockers,

38
Q

Aims in the use of antianginal drugs:

A

a. Treatment of acute attack - nitroglycerin very effective (i.v., sublingual, oral spray)
b. Short term prophylaxis - taking nitroglycerin prior to physical or emotional stress to prevent attack
c. Long term prophylaxis - objective is to reduce frequency of angina attacks. Many options are now available ie. long-acting nitrates, Ca++-blockers, β- blockers, aspirin, anticoagulants, thrombolytics

39
Q

Treatment of acute attack

A

nitroglycerin very effective (i.v., sublingual, oral spray)

40
Q

Short term prophylaxis

A

taking nitroglycerin prior to physical or emotional stress to prevent attack

41
Q

Long term prophylaxis

A

objective is to reduce frequency of angina attacks. Many options are now available ie. long-acting nitrates, Ca++-blockers, β- blockers,

Pharmacology Test #3 (9 decks)

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