Anti-hypertensives/ Anti-anginals Flashcards
Types of Angina
What causes stable angina?
Narrowing of coronary artery, causes ischemia during times of stress or physical exertion, predictable
Types of Angina
What causes Acute Coronary Syndrome (Variant angina)?
Vasospasm, reduces coronary blood flow
Types of Angina
What causes Unstable Angina?
Rupture of atherosclerotic plaque resulting in platelet adhesion and aggregation which reduces blood flow. Can be progressive and lead to MI
How do you treat variant angina?
Ca channel blockers
How do you treat unstable angina (Rx)
aspirin and statin therapy
Treatment of stable angina
Nitroglycerin (decreases contractility of smooth muscle tissue, dilates venous system primarily in CV system)
How does the reservoir of oxygen in the heart differ from that of other organs?
All of the oxygen is used in normal circumstances, with little left over. Other organs are overperfused. The only way to increase O2 is to increase coronary flow
How do you decrease ischemia in the heart
Decrease demand for O2 = decrease heart rate
what is pressure x radius / wall thickness
tension
how do you calculate coronary flow
aortic pressure (diastole) - LV pressure /coronary vascular resistance
What does nitroglycerin do to preload
decreases
How does the heart respond to localized ischemia?
Ischemic area sends out metabolic signals (adenosine and potassium) which cause dilation in the area of ischemia only so other areas don’t “steal” the increased blood flow
Why do we care about hypertension?
Most common CV disease
Primary cause of stroke
Decreasing diastolic number 5-6 mmHg decreases stroke risk by 35-40%
what is the formula to calculate BP
BP = CO x TPR
How do you calculate CO
CO = HR x SV
what is the top choice for treating HTN?
diuretics (thiazides)
where to thiazides target?
how do they work?
distal convoluted tubule
block Na-Cl cotransport causing lower blood volume
contraindication of thiazide diuretics
renal function impairment
side effects of thiazide diruetics
K loss
sexual dysfunction
increased risk of arrhythmias and QT prolongation (don’t combine with other drugs that do this)
What can you do for patients if you are concerned about K loss?
Prescribe a K sparing diuretic to add (not given alone)
Block Na channels in collecting duct to reduce K loss
which ace inhibitor and ARB do we need to know for this test?
captopril (ACEI) and losarten (ARB)
How does captopril work?
blocks conversion of angiotensin I to angiotensin II, prevents vasoconstriction
reduces aldosterone secretion -> reduces Na retention
In patients with which comorbidity should you definitely consider an ACE?
diabetes- slows progression of renal disease (but they also can cause renal failure in patients with renal artery stenosis and decreased GFR)
What is the common side effect associated with ACEI that requires change of therapy?
dry cough (high bradykinin levels)
How does losarten work?
ARB
Work similarly to ACEI
No increased bradykinin = no cough
Not as good in diabetics
Should you use ACEI or ARBs in pregnancy
Neither! Don’t do it!
What B-adrenergic receptor antagonist do we need to know? (Why can’t he just call them B blockers??)
propranolol
How does propranolol work?
reduces myocardial contractility and CO by blocking B1
beta blocker side effects
erectile dysfunction, depression, and insomnia
who to not use B blockers in and why?
Asthma- bronchoconstriction
Elderly and African Americans- doesn’t work as well, unknown why
what ca channel blockers do we need to know?
verapamil
amlodipine
how do ca channel blockers work?
decrease contractility due to low calcium
lowers vascular resistance
what is the most compelling difference between verapamil and amlodipine
nifedipine/amlodipine causes a sympathetic response to low BP and causes tachycardia
verapamil does not due to direct negative chronotropic response
side effects of ca channel blockers
cardiac depression, cardiac arrest,
bradycardia, peripheral edema, constipation (particularly common with verapamil), AV
block and congestive heart failure
ca channel blockers can increase risk of ischemia! When should you choose them?
for angina and arhythmia treatment, especially in the elderly and African American population
what vasodilators do we need to know?
hydralazine
minoxidil
sodium nitroprusside
how do vasodilators work
direct relaxation of arterial smooth muscle tissue
Why are vasodilators rarely prescribed
The reflex evoked increases in heart rate, contractility, plasma renin activity and fluid retention all counteract the
antihypertensive effect, must be administered with a sympatholytic (hydralazine and minoxidil)
How is sodium nitroprusside different from hydralazine and minoxidil
reduces contractility of arterioles and venules but only modest impact on HR
must be given by continuous IV (breaks down with exposure to sunlight)
