9. Diuretics used to treat hypertension

Question 1

What is the systolic pressure and diastolic pressure for stage 1, 2, and 3 of hypertension?

Answer 1

stage - 140-159/90-99
stage 2 - 160-179/100-109
stage 3 - >/= 180/ >/=110

Question 2

List some risk factors for hypertension.

Answer 2

excessive salt intake, smoking, increased lipids, diabetes, family history

Question 3

What % of hypertension has known causes vs. unknown causes?

Within the known cases, what are the 3 major causes?

Answer 3

known - 10 %
unknown - 90%

renal artery constriction, pheochromocytoma, hyperaldosteronism

Question 4

BP is directly related to what? What does the RAA mechanism alter? How does this mechanism increase BP?

Answer 4

renal perfusion
plasma volume
vasoconstriction

Question 5

Which receptors respond to lack of stretch in arterial walls? Once detected, where are the sensory impulses sent? Which centers respond? What is the response? Describe the effect of the 2 different impulses (motor vs. neural).

Answer 5

baroreceptors
CNS
Medullary cardiac and vasomotor
motor - sent to heart and veins: increase venous return & CO
neural - sent to resistance vessels: increase SVR

Question 6

What is urgency of treatment related to? What are some examples of lifestyle modifications?

Answer 6

urgency (capillaries cannot tolerate chronically high BP)

dietary salt restriction, weight loss, exercise

Question 7

BP control can be achieved through changes in 3 major things, what are they? What do diuretics influence?

Answer 7

CO, vasomotor tone, plasma volume

plasma volume

Question 8

What are diuretics used primarily to treat?

How can they restore cardiopulmonary function?

Answer 8

HTN, CHF

decreased plasma volume, eliminating excess tissue fluid, influence acid-base balance

Question 9

What is essential in treating HTN? Why?

Answer 9

multidrug therapy

compensatory mechanisms that assist with BP control

Question 10

List some challenges to medication compliance.

Answer 10

asymptomatic disease, long-term therapy, benefits nit tangible, undesirable side effects

Question 11

What % or CO do the nephrons receive? What does the nephron regulate?

Answer 11

20-25%

urine output/volume and physical and chemical characteristics

Question 12

List and describe the 3 mechanisms of diuresis.

Answer 12

glomerular filtration - UF enters glomerular capsule

tubular reabsorption - water, glucose, and electrolytes removed from UF; returned to blood

tubular secretion - waste products removed from plasma, added to filtrate for elimination

Question 13

Primary active transport:
How is Na reabsorbed?
How are the remaining ions reabsorbed?

Answer 13

sodium pump…reabsorbed by peritubular capillaries

passive diffusion

Question 14

Secondary active transport:
How is Na, K, and Cl moved from UF?
What then happens to K?
Na/Cl symporters cause additional what?

Answer 14

by the peritubular capillaries by Na, K, Cl (NKCC2) symporter

leaks back into filtrate

reabsorption of electrolytes and water in distal nephron

Question 15

What are the 5 groups of diruetics?

Answer 15

carbonic anhydrase inhibitors, osmotic diuretics, loop diuretics, thiazide diuretics, K sparing diuretics

Question 16

Which 2 classes of diuretics are not used as adjuncts to treat HTN or CHF?

Answer 16

carbonic anhydrase inhibitors and osmotic diuretics

Question 17

Acetazolamine (Diamox):

Class? MOA? Indications?

Answer 17

carbonic anhydrase inhibitor

prevents water and CO2 from combining in the PCT, decreasing carbonic acid, inhibits Na/H antiporter mechanism, causes metabolic acidosis, alkaline urine

glaucoma, metabolic alkalosis

Question 18

Mannitol (Osmitrol):

Class? MOA? Indications?

Answer 18

osmotic diuretic

increases UO without increased Na loss

acute renal failure prophylaxis during surgery, increased ICP and cerebral edema (neurosurgery)

Question 19

Furosemide (Lasix):
Class? Drug of choice for what? MOA? What effects will you see with IV administration? Indications? Formulations? Precautions? Adverse effects?

Answer 19

loop diuretic

pulmonary edema caused by CHF

acts on ascending limb, inhibits NKCC2 symporter (increase excretion of Na, Cl, K, H, Ca, Mg, and HCO3)

acute hemodynamic effects: vasodilation secondary to renal release of prostaglandins (decreased PCWP/BP/SVR)

CHF, pulmonary edema, HTN, Ascites +/- liver cirrhosis, renal failure, SIADH, increased Ca or Mg

oral/parenteral preparations

hypokalemia, metabolic alkalosis, increased risk of digxon toxicity

volume depletion, dizziness, N & V, orthostatic hypotension, muscle weakness, arrhythmia

Question 20

Chlorothiazide (Diuril):

Class? Formulations? Duration? MOA? Indications? Contraindications?

Answer 20

thiazide diuretic

oral/parenteral (act on distal tubule)

6-12hrs

inhibit Na/Cl symporter (natriuretic effect, chloruretic effect, diuretic effect), mild inhibition of carbonic anhydrase in PCT

edema, mild HTN

anuria, hypersensitivities

Question 21

What are the 2 types of K+ sparing diuretics?

Answer 21

aldosterone antagonists and direct-acting

Question 22

Spironolactone (Aldactone):

Class? MOA? General onset/DOA? Results in what? Indications? Precautions?

Answer 22

aldosterone antagonist

blocks hormone to prevent Na and water reabsorption from filtrate

slow onset, long DOA

increased Na and Cl excretion, decreased K excretion

HTN caused by increased aldosterone secretion

K retention (hyperkalemia)

Question 23

Amiloride (Midamor):

Class? MOA? Useful in treatment of?

Answer 23

direct-acting

act on DCT to inhibit Na reabsorption and K secretion causing rapid diuresis

edema secondary to heart failure