Angina, blood pressure, hypertension, medications

Stable angina

Chest pain triggered by stress, exertion, or cold; relieved by rest or nitroglycerin

Unstable angina

Unpredictable chest pain that occurs at rest / with minimal exertion; not fully relieved by rest or nitroglycerin- may signal impending MI

Prinzmetal (variant) angina

Chest pain that occurs at rest due to coronary artery spasm; often occurs at night

Prinzmetal (variant) angina often responds to…

calcium channel blockers and nitroglycerin

Nitroglycerin mechanism of action

Nitrate vasodilator that causes venous dilation, reducing preload and myocardial oxygen demand; lowers BP

Adverse effects of nitroglycerin

• Headache/dizziness

• Hypotension

• Reflex tachycardia

Nitroglycerin routes of adminstration

IV and sublingual

What should a patient do when taking sublingual nitroglycerin for chest pain?

Take at onset of prescribed pain, repeat after 5 minutes if needed. If no relief after the second dose, call 911

When is nitroglycerin contraindicated

• Severe anemia

• Head injury

• Erectile dysfunction medication

• Use with caution in pregnancy, glaucoma, liver dysfunction

Nitroglycerin nursing considerations

• Monitor BP, chest pain, adverse effects

• Use gloves

• Have pt be medication free for 10-12 hours a day

• Educate to avoid use of alcohol

Hypertension

Persistently elevated BP- above 120/80

Systolic BP

Force of blood against artery walls when the heart beats/contracts

Diastolic BP

Force of blood against artery walls when the heart rests and fills

BP formula

Cardiac output x systemic vascular resistance (CO x SVR)

Cardiac output formula

HR x SV

Primary hypertension

Hypertension that has no single identifiable cause, associated with age, genetics, lifestyle factors (most common cause of HTN)

Secondar hypertension

Hypertension caused by an identifiable underlying condition/medication, such as kidney disease, thyroid disorders

Affects of hypertension on the heart

• Increased cardiac workload

• Coronary artery disease

• Heart failure

• Thickening of heart muscle

What triggers the renin-angiotensin-aldosterone system (RAAS)?

• Low BP

• Low blood volume

• Reduced renal perfusion

Sequence of RAAS pathway

1. Kidneys release renin

2. Angiotensinogen —> angiotensin I

3. ACE converts angiotensin I —> angiotensin II

4. angiotensin II causes vasoconstriction and promotes aldosterone release

5. Aldosterone promotes sodium and water retention, increase BP and blood volume

What regulates BP

• RAAS

• Autonomic nervous system

• Hormones

• Vascular endothelium

Diuretic mechanism of action

Increase sodium/water excretion, reducing circulating blood volume and blood pressure

Loop diuretic

Blocks reabsorption of sodium and water, increases kidney excretion of water, potassium, sodium, and other electrolytes

High ceiling loop diuretic uses

• Congestive heart failure / peripheral edema

• Liver cirrhosis

• Hypertension

High ceiling loop diuretic adverse effects

• dehydration

• hypotension

• hypokalemia / hyponatremia

• hyperglycemia

• ototoxicity

High ceiling loop diuretic contraindications

• anuria

• severe liver disease

• dehydration

• caution with diabetes and pregnancy

suffix for loop diuretics

“-semide”

suffix for thiazide diuretics

“-thiazide”

Thiazide diuretic uses

• Hypertension

• Fluid retention / edema (especially from heart failure or kidney disease)

Thiazide diuretic adverse effects

• Hypokalemia / hyponatremia

• Dehydration

• Hypotension

• Hyperglycemia

• Other electrolyte imbalances

First medication of choice for hypertension

thiazide diuretics

When should patients take diuretics

in the morning

How do loop diuretics differ from thiazide diuretics?

• Loop diuretics act on loop of Henle and increase calcium excretion

• Thiazide diuretics act on distal convoluted tube and decrease calcium excretion

• Both increase excretion of sodium, water, and potassium

potassium sparing diuretic suffix

“-actone”

Mechanism of action for potassium-sparing diuretics

Blocks action of aldosterone (sodium and water retention) causing potassium retention and sodium/water excretion

Why does hypokalemia increase the risk of digoxin toxicity?

Hypokalemia increases heart's sensitivity to digoxin, raising the risk of toxicity and dysrhythmias

What is mannitol

Osmotic diuretic, reduces intracranial and intraocular pressure

Effects of Beta blockers (Beta-adrenergic antagonists)

• Decreases HR + contractility/workload

• Decreases renin release (causing vasodilation and water/sodium secretion)

• Decreases O2 demands on the heart

Suffix for beta blockers

“-olol”

Different types of beta blockers

1. Cardioselective

2. Nonselective

3. Mixed Alpha and Beta blockers

Cardioselective beta-1 blockers affect…

The heart (decrease HR and force of contraction)

Nonselective beta-1 blockers affect…

Both beta1 and beta 2 receptors- both heart and lungs

Why must nonselective beta blockers be used cautiously in asthma or COPD?

Beta-2 block can cause bronchoconstriction and wheezing

Adverse effects of beta blockers

• Bradycardia

• Fatigue

• Dizziness

• Hypotension

Suffix for ACE inhibitors

“-pril”

ACE inhibitors mechanism of action

Blocks ACE, reducing production of angiotension I to angiotension II

ACE inhibitors lead to…

• Vasodilation

• Sodium / water excretion

• Decreased afterload

When are ACE inhibitors commonly used

• HTN

• HF

• MI

Adverse effects of ACE inhibitors

• Dry cough

• Hypotension

• Hyperkalemia

• Angioedema

• Dizziness

Angiotensin II receptor blockers (ARBs) suffix

“-sartan”

ARBs mechanism of action

Blocks action of angiotensin II in the body

Effects of ARBs

• Vasodilation

• Excretion of water and sodium

ARBs are used for…

• Hypertension

• HF

• Stroke + MI prevention

Adverse effects of ARBs

• Hypotension

• Hyperkalemia

• Angioedema

• Dizziness

What do direct renin inhibitors do

Suppresses RAAS activity, decreasing BP

Calcium channel blocker suffix

“-dipine”

Calcium channel blockers mechanism of action

Blocks calcium channels, relaxing vascular smooth muscle —> vasodilation

Adverse effects of calcium channel blockers

• Bradycardia

• Hypotension

• Peripheral edema

Alpha adrenergic blockers suffix

“-azosin”

Alpha adrenergic blockers mechanism of action

blocks alpha 1 receptors, causing venous/arterial dilation (decreased vascular resistance)

IV medications used in hypertensive crisis

• Nitroprusside

• Nitroglycerin

• Nicardipine

How does nitroprusside lower BP

Causes arterial and venous vasodilation

How is BP of 190/98 or above treated

Combination of two drugs: thiazide diuretics + ACE inhibitors/calcium channel blocker

What is orthostatic hypotension

fall in blood pressure when changing from lying down/sitting to standing

What blood pressure change meets the usual definition of orthostatic hypotension?

Decrease of at least 20 mmHg systolic or 10mmHg diastolic within 3 minutes of standing

How should a nurse assess orthostatic blood pressure?

1. Measure BP + HR while lying down

2. Reassess 1 minute after standing

3. Reassess after 3 minutes

What medications are used for hypertension

• Diuretics

• Beta blockers

• ACE inhibitors

• ARBs

• Calcium channel blockers

• Direct renin inhibitor

• Alpha adrenergic blockers

• Vasodilators