Pharm110 Chp 20 Diuretics and Antihypertensives

Question 1

Cardiac performance

Answer 1

Determined by:

• Preload (how much blood is entering the R. Atrium)
• Afterload (pressure L. Ventricle has to exert to get blood out to the system)
• Contractility (hears ability to contract)
• Heart rate

The larger the amount of blood in the ventricle, the higher the preload.

Question 2

Diuretics

Answer 2

Remove excess fluid which results in:

• Decreased preload
• Decreased cardiac output
• Decreased total peripheral resistance

-Decreased workload of the heart and decreased blood pressure

Question 3

Thiazide diuretics

Answer 3

Prefix “zide”
Action:
-Inhibit Na+ and Cl- reabsorption in the DCT.
More Na+ enters the DCT increasing the Na+ - K+ exchange and could lead to hypokalemia.

Adverse effects:

• Loss of potassium, check K+ level (normal 3.5-5)
• Loss of sodium and chloride (normal Na+ 135-145)
• Hyperglycemia

For every Na+ absorbed into blood the kidneys excrete a K+

Teaching:

• K+ chloride supplements required
• Encourage to eat oranges and bananas

Question 4

Loop Diuretics

Answer 4

Prefix “mide” e.g. furosemide (Lasix)
Action:
-Increase excretion of Na+ and Cl- by inhibiting reabsorption in the DCT, PCT and loop of Henle, 3 sites of action increasing their effectiveness as diuretics.
-More potent than Thiazides

Adverse effects:

• Dry mouth
• Potassium depletion (Hypokalemia)
• Fatigue
• Dehydration
• Hypotension

Question 5

Potassium-Sparing Diuretics

Answer 5

e.g. spironolactone
Action:
-Inhibit aldosterone
-Bind aldosterone receptors and block the reabsorption of sodium and water
-Conserve potassium

Adverse effect

• Hyperkalemia (excessive K+ levels)
• Drowsiness
• Mental confusion

Question 6

Osmotic Diuretics

Answer 6

e.g. Mannitol
Action:
-Produces a profound diuretic effect
-Used to treat intracranial pressure and renal failure

Adverse effects:
-IV tissue necrosis

Question 7

Carbonic Anhydrase Inhibitors

Answer 7

e.g. Acetazolamide (Diamox)
Action:
-Inhibit carbonic anhydrase, enzyme that maintains alkalinity of the blood and normal pH levels.
-Results in excretion of Na+, K+, bicarbonate, and H2O.

-Only used to treat glaucoma

Adverse effects:
-Blood pH to become acidic

Question 8

Combination Potassium sparing and Hydrochlorothiazide

Answer 8

Action:

-Decreases adverse effects (Hypokalemia from thiazides and Hyperkalemia from potassium sparing diuretics)

Question 9

Diuretic administration and nursing implications

Answer 9

Before admin, measure fluid I&O and report to Dr. any marked decrease in output.

Patients with edema caused by HF or other causes are weighed DAILY.

Measure and record I&O every 8 hours

Give Early in the morning to avoid night time urination

Most common adverse effect is the loss of fluid and electrolytes

Most common imbalances are loss of potassium and water.

Encourage to eat and drink between meals and in the evening when allowed.

Question 10

Diuretic warnings and pt teaching

Answer 10

Notify Dr. if

• Pt. fails to dring adequate amount of fluid
• If urine output is low
• If urine appears concentrated
• Pt. appears dehydrated
• If S/S of an electrolyte imbalance are apparent.

Pt and family teaching

• Do not reduce fluid intake
• Avoid alcohol (it is also a diuretic)
• Rise slowly
• Weigh yourself weekly
• Wear sunscreen (photosensitivity)

Question 11

Diuretics and Antihypertensives

Answer 11

Effect control of BP, diuretics frequently given in combination with another class of hypertensives

Question 12

ACE Inhibitors

Answer 12

Prefix “pril”
Action:
-Antagonists to angiotensin-aldosterone system
-Prevent Angiotensin I conversion to Angiotensin II, produces potent vasoconstriction and stimulation of aldosterone.
-Result in vasodilation, decreased BP, decreased systemic vascular resistance and decreased afterload

Adverse effect:
-Dry non-productive cough

Question 13

Angiotensin II antagonists

Answer 13

Prefix “sartan”
Action:
Allow Angiotensin I to convert to Angiotensin II, but block the receptors that receive Angiotensin II
-Block vasoconstriction and release of aldosterone
-Lower BP
-Well tolerated, coughing not a concern

Question 14

Calcium channel blockers

Answer 14

e.g. Amlodipine
Action:
-1st drug for hypertension treatment
-Dilate peripheral arterioles and reduce peripheral resistance
-Reduce arterial blood pressure at rest and during exercise

Adverse effects:

• Hypotension
• Palpations
• Tachycardia

Question 15

Beta-adrenergic blocking agents

Answer 15

prefix "olol"
Action:
-Inhibit beta1 and beta2 receptors in the heart and lungs, or just the heart
-Reduce heart rate
-Force contraction

Adverse effects:
-Bronchoconstriction

Question 16

Vasodilators

Answer 16

Action:

• Directly dilate the peripheral arterioles
• Lower BP

Question 17

Peripherally acting Antiadrenergic agents

Answer 17

Action:

• Block alpha1 receptors
• Deplete norepinephrine
• Block adrenergic receptors
• Prevent sympathetic nervous system stimulation

Adverse effects:

• Depression
• Hypotension

Question 18

Centrally acting antiadrenergic agents

Answer 18

e.g. Clonidine
Action:
-Not clear
-Theory, Norepinephrine and epinephrine is decreased
-Directly stimulate alpha-adrenergic receptors in the CNS, thereby resulting in dilation of peripheral blood vessels and reduction blood pressure.

Adverse effect:

• Sedation
• Orthostatic hypotension

Client teaching
-Do not stop abruptly, rebound hypertension crisis can occur