CV Medications Part 1

Question 1

Diuretics

Answer 1

Decrease the plasma and extracellular fluid volumes by promoting excretion of sodium & water

Results:
Decreased preload
Decreased afterload
Reduced workload of the heart, and decreased blood pressure

Question 2

Thiazide diuretics

Answer 2

The most commonly used diuretics for hypertension; first line

Question 3

Adrenergic Receptors

Answer 3

Alpha 1
Vasoconstriction
BP increases

Alpha 2
Receptors within the brain
Decreases Norepinephrine 
Inhibits SNS 
Decreases vasoconstriction & HR 

Beta 1
Increase HR (chronotropic effect)
Increases speed of contraction
Increase cardiac muscle contractility (inotropic effect)

Beta 2
Bronchiole dilation (targeted when treating asthma attacks) & some peripheral dilation

Question 4

Peripheral α1-blockers/antagonists

Answer 4

Blockage of postsynaptic alpha-1 adrenergic receptors

-zosin

Alpha 1:
Vasoconstriction of coronary arteries/veins

Results in:
Vasodilation of arteries & veins
Reduction in standing and lying blood pressure
Substantial first-dose effect of hypotension

Question 5

Centrally acting α2-receptor agonists

Answer 5

Stimulate α2-adrenergic receptors in the brain
(Alpha 2: Vasodilatation of arteries)

Sympathetic outflow from the CNS is decreased
Norepinephrine production is decreased leading to vasodilitation
Stimulation of the α2-adrenergic receptors reduces renal vascular resistance (protects kidneys)

Result: decrease in BP, HR, vasoconstriction, renal vascular resistance

Drug: Clonidine (Catapress)

Adverse Effects: Dry mouth, drowsiness, dizziness, sedation, and constipation
Rebound hypertension with abrupt discontinuation

Question 6

β-blockers

Answer 6

-olol
Reduce BP by reducing heart rate & contractility through β1-blockade
Long-term use causes reduced peripheral vascular resistance
Cause reduced secretion of renin

Common Drugs:
metoprolol (Lopressor)

Result: decreased blood pressure & HR
NOT good for a patient with pulmonary edema

Adverse Effects: Wheezing, bradycardia, unusual dreams, hypotension, Heart Failure

Question 7

Dual-action α1- and β-receptor blockers

Answer 7

Block the α1-adrenergic receptors
Reduction of heart rate (β1-receptor blockade)
Vasodilation (α1-receptor blockade)

Common Drugs:
Labetalol (AB in name = A/B receptor blocker)

Result: decreased blood pressure

Question 8

Labetalol

Answer 8

Management of acute, severe hypertension after acute ischemic stroke

Complete absorption after oral administration: Lay down! Can cause orthostatic event

Question 9

Contraindications to Labetalol

Answer 9

Contraindications
Severe bradycardia, second- or third-degree heart block, bronchial asthma, overt uncompensated heart failure, and cardiogenic shock

Precautions
Patients with history of heart failure, emphysema, bronchitis, diabetes mellitus, or impaired hepatic function: can cause hypoglycemia

Adverse Effects
Orthostatic hypotension, Weakness, fatigue, and dizziness, Overdose effects: posture sensitive hypotension and excessive bradycardia, Bronchospasms

Question 10

Angiotensin Converting

Enzyme (ACE) Inhibitors

Answer 10

Large group of safe and effective drugs
Often used as first-line drugs for HF
and hypertension
May be combined with a thiazide diuretic or calcium channel blocker
Most ACE inhibitors are prodrugs* (except for captopril and lisinopril)

Result: increased blood volume, increased preload, and increased BP

Question 11

ACE Inhibitors Cont.d

Answer 11

ACE inhibitors block the angiotensin converting enzyme, thus preventing the formation of angiotensin II

Result:
decreased peripheral vascular resistance (afterload), vasodilation, and therefore decreased blood pressure
Decreased sodium retention, decreased water retention, therefore decreased circulating volume and decreased blood pressure
Increased cardiac output without increase in HR

Question 12

ACE Adverse Effects

Answer 12

Potassium, Sodium levels, BP, Dry cough, angioedema, neutropenia (white blood cells)

Question 13

Angiotensin II Receptor Blockers (ARB’s)

Answer 13

-sartan
Also known as ARBs
Do not cause a dry cough
Allow angiotensin I to be converted to angiotensin II, but block the receptors that receive angiotensin II
Block vasoconstricting effects of angiotensin II and release of aldosterone
Aldosterone retains Sodium (and water) and excretes Potassium

Interactions
Potassium supplements
Grapefruit decreases effectiveness of losartan by slowing conversion of losartan to its active form

Question 14

Calcium-Channel Blockers

Answer 14

-pine
Cause smooth muscle relaxation by blocking the binding of calcium to its receptors, preventing muscle contraction
Dilates coronary vessels & peripheral arteries
Causes decreased peripheral resistance and BP
Decreases impulse formation

Result:
decreased blood pressure and decreased heart rate
Reduce the workload of the heart
Decreased myocardial oxygen demand

Question 15

CCB Drugs that also work like anti-arrythmics

Answer 15

Specifically approved as antiarrhythmics:
verapamil
diltiazem

Question 16

When should you use CCB’s?

Answer 16

Angina
Prinzmetal’s angina: vasospastic angina, smokers/Reynaud patients, random chest pain, possibly during sleep
Hypertension
Raynaud’s Disease

Adverse Effects:
Peripheral Edema
Constipation (w/ verapamil), nausea
Hypotension, palpitations, reflex tachycardia
COnstipation

Question 17

Nifedipine

Answer 17

The dihydropyridines of the CCBs
Acts mainly on vascular smooth muscle
Blocks calcium channels in vascular smooth muscle – vasodilation
Given for angina, hypertension

Question 18

Vasodilators

Answer 18

Second-line agents
Result: decreased systemic vascular resistance, decreased afterload, and peripheral vasodilation

Common Drugs:
Hydralazine HCl (Apresoline)
Diazoxide (Hyperstat)
Minoxidil (Loniten)
Sodium nitroprusside (Nipride, Nitropress)

Sodium nitroprusside (Nipride) and intravenous diazoxide (Hyperstat) are reserved for the management of hypertensive emergencies or hypertensive crisis

Question 19

Hydralazine (Vasodilator)

Answer 19

Palpitations, reflex tachycardia, nausea and vomiting, edema, symptoms of SLE with high doses/prolonged use, others

β blocker or clonidine
Reduces adverse effect of reflex tachycardia
Diuretic
Offsets fluid retention/edema from increased renin activity

May need vitamin B supplement