HYPERTENSION!!!




Question: What is hypertension?

Answer: The term used to describe high blood pressure. 90% of all cases are idiopathic, or of unknown causes, and 10% of all cases have a known cause such as a tumor or other disease processes.


Classification and management of hypertension is based on 4 stages:
  • normal: 120/80external image images?q=tbn:ANd9GcRnSjBAi8seaUskuoieTPStwzm3z8cQlYDHMSpdLrr9TBMwMh3faw
  • prehypertension: 120-139/80-89
  • stage 1: 140-159/90-99
  • stage 2: 160+/100+ (this is a medical emergency. Patients with a high blood pressure should see their physician as soon as possible)

Question: Why is blood pressure so important to monitor?

Answer: Hypertension is the THIRD leading cause of death throughout the world. People with hypertension have a greater risk of MIs, heart failure, renal, and hepatic disease.


ANTIHYPERTENSIVE DRUGS!!!

Adrenergic drugsexternal image images?q=tbn:ANd9GcRorRrFOfoACbOR6ceyuuX08Bvr1sAJQnhBGE9BmcURn0DoRrJRZw
Angiotension converting enzyme inhibitors (ACE)

Angiotension II receptor blockers (ARB)
Calcium Channel Blockers
Diruetics
Vasodilators


ADRENERGIC DRUGS:

alpha-blockers and combined alpha/beta-blockers.
five subgroups:
  • centrally and peripherally acting adrenergic neuron blockers
  • centrally acting alpha2 receptor agonists
  • peripherally acting alpha1 receptor bloclkers
  • peripherally acting beta receptor blockers (BETA BLOCKERS)
  • Peripherally acting dual alpha1 and beta receptor blockers

ANGIOTENSION CONVERTING ENZYME INHIBITORS (ACE):external image figure55l.jpg

Mechanism of action:
-the venom of a South American Viper was found to inhibit kininase. Kininase is an enzyme that breaks down bradykinin which is a potent vasodilator in the human body.
-the primary effects of the ACE inhibitors are cardiovascular and renal. Their cardiovascular effects are due to their ability to reduce blood pressure by decreasing SVR.
-they do this by preventing the breakdown of the vasodilating substance bradykinin and also of substance P.
-these combined effects decrease afterload, or the resistance against which the left ventricle must pump to eject its volume of blood during contraction.

ACE inhibitors are beneficial in the treatment of heart failure because they prevent sodium and water resorption by inhibiting aldosterone secretion. This causes diuresis which decreases the blood volume.

Indications:
-hypertension
-left ventricular hypertrophy
-diabetic patients ( ACE inhibitors have a protective effect on the kidneys because they reduce glomerular filtration pressure. They also prevent the progression of nephropathy)

Contraindications:
-drug allergy
-high baseline Potassium level (these drugs can promote hyperkalemia)
-lactating women
-children
-bilateral renal artery stenosis

Adverse Effects:
-fatigue
-dizziness
-mood changes
-headaches
-dry, nonproductive cough
-first dose hypotensive effect
-hyperkalemia

Examples:
-Captopril (capoten)
-Analapril (vasotec)
-Lisinopril (prinivil and zestril)

The story of Angie and Al - credit to npetges.


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ANGIOTENSIN II RECEPTOR BLOCKERS:

ARBs
external image images?q=tbn:ANd9GcQdMVwDYfXbNg_EEOQ_bL-Xg64xvu1yloAlCBSDUp-sszuH9jTt

CALCIUM CHANNEL BLOCKERS

Mechanism of action
-Relaxes smooth muscle by blocking and binding calcium to its receptors preventing muscle contraction
-Resulting in decreased peripheral smooth muscle tone and decreased systemic vascular resistance = decreased blood pressure :)

Indications
Angina
Hypertenstion
Dysrhythmias
Migraine headaches
Raynaud's disease

Side effects
Hypotenstion, palpitations, tachycardia
Constipation, nausea
Rash, flushing, peripheral edema, dermatitisexternal image US.jpg

Examples
Benzothiazepines
Phenylakamines
Dihydropyridines

DIURETICS

-Decreases the plasma and extracellular fluid volumes
-------> decreased preload, cardiac output, total peripheral resistance

*Decreased workload of the heart and decreased blood pressure :) *


VASODILATORS

Mechanism of action
-directly relax arteriolar smooth muscle
-resulting in decreased systemic vascular response, decreased afterload, and peripheral vasodilation :)

Indications
Hypertension
May be used in combination with other agents
IV sodium nitroprusside and diazoxide are reserved for hypertensive emergencies---- used in the hospital setting

Side effects
Hydralazine:
dizziness, headache, anxiety, tachycardia, nausea and vomiting, diarrhea anemia, dyspnea, edema, nasal congestion

Sodium nitroprusside:
Bradycardia, hypotension, possible cyanide toxicity

-Dose dependent

Examples
Hydralazine
Sodium nitroprusside
-Dose dependent

Nursing Implications
Instruct patient to change positions slowly to avoid syncope from postural hypotension

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