Chapter 26 and 29 Drug therapy for Hypertension and Hypotension

What is the formula for cardiac output?

Cardiac Output = Stroke Volume × Heart Rate

What is preload?

Amount of blood returning to the heart; volume at the end of diastole; patient's fluid/hydration status ("pool")

What do "Pool, Pipes, and Pump" mean?

• Pool = Preload (blood volume/fluid status)

• Pipes = Afterload (arterial resistance)

• Pump = Contractility (heart strength)

How does aldosterone affect blood pressure?

It causes the body to retain sodium and water, increasing blood volume (preload).

What is afterload?

Resistance in the arteries ("pipes")

How does the RAAS system raise blood pressure?

Causes vasoconstriction (increases afterload) and retains sodium/water (increases preload).

What is contractility?

The heart's ability to pump ("pump")

How does the sympathetic nervous system increase blood pressure?

Increases heart rate, increases contractility, and causes vasoconstriction.

What is systole?

Contraction of the ventricles; heart pumping

What is diastole?

Ventricles relaxing and refilling with blood

Define Chronotropic effects

Chronotropic: Affects Heart Rate (+ increases, - decreases)

Define Dromotropic effects

Dromotropic: Affects the speed of electrical conduction (+ speeds up, - slows down).

Define Inotropic effects

Inotropic : Affects myocardial contractility/pump strength (+ contracts harder, - contracts with less strength).

What does normotensive mean?

Normal blood pressure

Describe the step-by-step cascade of the Renin-Angiotensin-Aldosterone System (RAAS) when BP drops

1. Low BP causes the kidneys to trigger the pathway.

2. Renin converts angiotensinogen to Angiotensin I.

3. ACE (in the lungs) converts Angiotensin I to Angiotensin II.

4. Angiotensin II causes potent vasoconstriction (increases afterload).

5. The adrenal gland releases aldosterone, which reabsorbs sodium and water (increases preload).

What does the sympathetic nervous system do to blood pressure?

Increases heart rate, contractility, and vasoconstriction

What does angiotensin II do?

Vasoconstriction → increases afterload

What does aldosterone do?

Retains sodium and water → increases preload

What does the RAAS system ultimately cause?

Increased blood volume and vasoconstriction

What is hypertension?

Persistently high blood pressure from abnormalities in regulatory mechanisms

What are major complications of hypertension?

MI, CHF, stroke, renal disease, retinal damage

what ranges define Stage 2 Hypertension vs. a Hypertensive Emergency?

• Stage 2 HTN = ≥140 OR ≥90

• Hypertensive Emergency = ≥180 OR ≥120

BP goal for adults >60 years?

<150/90

BP goal for adults <60 years?

<140/90

BP goal for patients with diabetes or CKD?

<140/90

Lifestyle changes for hypertension?

Stress management, reduce sodium, reduce fat/cholesterol, exercise, stop tobacco, maintain weight, increase fruits/vegetables, limit alcohol

What do ACE inhibitors do?

Block conversion of angiotensin I to angiotensin II

How do ACE inhibitors lower blood pressure?

They block angiotensin II, causing vasodilation (wider arteries) and decreased resistance in the arteries (afterload).

How do ACE inhibitors affect preload?

Decrease preload by decreasing aldosterone

ACE inhibitor all end in?

-pril

Examples of ACE inhibitors?

• Captopril

• Lisinopril

ACE inhibitor memory trick?

"In APRIL my blood pressure decreases"

What type of Adverse effects does a ACE inhibitors have?

Black box warning : Pregnancy

Angioedema - Swelling of lips, tongue, mouth, airway

ACE cough - Dry cough caused by lung effects

Hyperkalemia - High potassium because aldosterone is blocked

Why does orthostatic hypotension occur with ACE inhibitors as an adver effect?

Decreased preload

What foods should patients avoid on ACE inhibitors?

High potassium foods (bananas, oranges)

What supplements should patients avoid on ACE inhibitors?

Potassium supplements and potassium salt substitutes

Can ACE inhibitors be taken during pregnancy?

No

What do ARBs do?

Directly blocks Angiotensin II at the receptor site on blood vessels, leading to vasodilation

How do ARBs lower blood pressure?

They block angiotensin II receptors, causing vasodilation and reducing fluid retention.

ARB ending?

-sartan

Examples of ARBs?

• Losartan

• Valsartan

Major adverse effects of ARBs?

• GI effects

• orthostatic hypotension

• hyperkalemia

Which occurs less with ARBs compared to ACE inhibitors?

Cough and angioedema

Black box warning for ARBs?

A: Pregnancy

What does Beta-1 stimulation normally do?

Increase HR, contractility, conduction

What does Beta-2 stimulation normally do?

Bronchodilation

What does Alpha-1 stimulation normally do?

Vasoconstriction

What do beta blockers decrease?

Heart rate, contractility, electrical conduction

Beta blocker ending?

-olol

Selective beta blocker example? (Selective works on beta 1)

Metoprolol

Nonselective beta blocker example? (nonselective works on both beta 1 and 2)

Propranolol

Alpha-beta blocker examples?

• Carvedilol

• Labetalol

How do alpha-beta blockers lower blood pressure?

Slow the heart rate, decrease contractility, and cause vasodilation.

Major side effect of beta blockers? - Adverse effect

Bradycardia

Why are nonselective beta blockers dangerous in asthma/COPD? - Adverse effect

Cause bronchoconstriction

What can beta blockers mask? - Adverse effect

Hypoglycemia

What happens if beta blockers are stopped abruptly?

• Risk of MI

• chest pain

• lethal dysrhythmias

What should be monitored with beta blockers?

Blood pressure and heart rate

What should diabetic patients monitor?

Blood glucose

Alpha-1 blocker ending? - Antiadrenergics

-zosin

Examples of Alpha 1 blockers?

Doxazosin

Major adverse effect for Antiadrenergics?

First-dose phenomenon

What is first-dose phenomenon? How would you fight it?

PT can get Orthostatic hypotension, dizziness, syncope after first dose.

Fight it by: Take med at bedtime

Most important alpha-2 agonist?

Clonidine

What do calcium channel blockers do?

Inhibit the movement of calcium across the membranes of heart & arterial muscle cells which causes vasodilation of the peripheral vasculature

How do calcium channel blockers lower blood pressure?

Cause vasodilation of arteries, lowering resistance.(afterload)

Calcium Channel Blockers Drug ending?

-pine

Pine tree = wide = widen arteries

Example of Calcium Channel Blockers?

• Amlodipine

• Nicardipine

Calcium Channel Blockers adverse effects?

• Flushing

• muscle cramps

• edema

• headache

• dizziness

• hypotension

Can calcium channel blockers cause sexual dysfunction?

Yes

Which calcium channel blocker can be IV?

Nicardipine

How do diuretics lower blood pressure?

Remove excess water and fluid from the body.

Example of a thiazide diuretic?

Hydrochlorothiazide (HCTZ)

What do thiazide diuretics increase excretion of?

They block sodium reabsorption, increasing excretion of sodium, water, and potassium.

Example potassium-sparing diuretic?

Spironolactone (Blocks aldosterone)

What electrolyte abnormality can occur in Spironolactone (Blocks aldosterone)?

Hyperkalemia

Example loop diuretic? (works in the Loop of Henle and wastes potassium)

Furosemide

What electrolyte abnormality can occur in Furosemide?

Hypokalemia

BP defining hypertensive emergency?

≥180 systolic OR ≥120 diastolic

Why are IV drugs used in hypertensive emergency?

Need rapid BP reduction

Direct vasodilator example in hypertensive emergency?

Hydralazine

IV-only vasodilator example in hypertensive emergency?

Nitroprusside

Nitroprusside toxicity?

Thiocyanate toxicity

Signs of thiocyanate toxicity?

N/V, muscle twitching, seizures

Definition of hypotension?

SBP <90 and/or DBP <60 WITH symptoms

Why is hypotension dangerous?

Decreased oxygen delivery to tissues

During hypotension what organs are especially affected?

Kidneys

What is shock?

Compromised oxygen delivery, consumption, or utilization causing tissue hypoxia

Hypotension is a clinical indicator of what?

Shock

What causes hypovolemic shock?

Not enough circulating blood/fluid volume. (preload)

Distributive shock problem? Type of shock

Problem with the pipes ( Afterload)

Cardiogenic shock problem? Type of shock

Problem with the Contractility ("pump")

What are vasopressors?

Drugs that increase blood pressure

Another name for vasopressors?

Adrenergic agonists

What does Beta-1 stimulation cause?

Increased heart rate and contractility.

Major adverse effects for Norepinephrine (Levophed)?

• Limb ischemia

• Cardiac dysrhythmias

• decreased organ perfusion

Which vasopressor stimulates everything? Other Vasopressors

Epinephrine

Which vasopressor is used in anaphylactic shock? Other Vasopressors

Epinephrine

Dopamine effects? Other Vasopressors

Beta-1 and Alpha-1 stimulation (dose dependent)

Dobutamine action? Other Vasopressors

Beta-1 agonist; increases contractility