Drugs for Cardiac - Diuretics

Question 1

hypertension (what is it?)

Answer 1

chronic progressive disorder that damages walls of blood vessels –> hypertrophy/hyperplasia of vessel lining –> causes target organ damage
- asymptomatic until long after injury

Question 2

Primary (essential) HTN

Answer 2

• has no identifiable cause

Question 3

Secondary HTN

Answer 3

• HTN is secondary to another disease

- not as common as primary

Question 4

Therapeutic goals: HTN

Answer 4

• keep BP < 140/90 (keep even lower w/diabetes Mellitus and CHD)
• drug therapy and minimize drug side effects
• lifestyle modifications
• individualized therapy

Question 5

types of drugs for HTN

Answer 5

1. diuretics
2. drugs that act on sympathetic NS
3. drugs that act on RAAS
4. calcium channel blockers (CCB)
5. vasodilators

Question 6

Diuretics

Answer 6

1. MOA - block Na+ and H20 reabsorption –> ⇡ excretion of solute and water (& Cl-)
2. “High ceiling” effects - drugs that act on a part of the nephron that blocks the largest amt of solute reabsorption
3. Indications: HTN, HF, CKD

Question 7

Loop diuretics

Answer 7

• for HTN
• act on the Loop of Henle (20%) of reabsorption takes place there
• Furosemide (Lasix)
• Bumetanide (Bumex) - 40x stronger than Furosemide

Question 8

Furosemide (Lasix)

[also, Bumetanide (Bumex) = 40x stronger)

Answer 8

MOA - loop diuretic b/c block reabsorption of Na+/Cl- at (ascending limb) Loop of Henle

Indications: pulmonary edema (PE), pulmonary congestion (PC), HTN

Route: PO, IVPush (acts w/in 5 min), IM

S/Sx - distended jugular (w/PE)

Question 9

SE of Furosemide (Lasix)

Answer 9

CV = hypotension
Fluid/electrolyte imbalance
  = FVD (severe dehydration)
  = hypokalemia (give K+ supplement)
  = hyponatremia

Ototoxicity - transient hearing loss

Metabolic
= hyperglycemia
= hyperurecemia (high uric acid = gout attack)

Question 10

5 major categories of diuretics

Answer 10

1. loop diuretics
2. thiazide diuretics
3. osmotic diuretics
4. potassium-sparing diuretics
   
   • aldosterone antagonists
   • nonaldosterone antagonists
5. carbonic anhydrase inhibitors - used primarily to ↓ IOP (not to ⇡ urine output)

Question 11

Drug interactions w/Furosemide

Answer 11

Digoxin (treats HF & dysrhythmia) - loss of K+ from Furosimide ⇡ risk of Digoxin toxicity

• S/Sx = ventricular disrhythmia
• NIs = monitor K+ levels

K+ sparing diuretic helps counterbalance the K+ loss

Question 12

Thiazides

aka Hydrochlorothiazide / HCTZ

Answer 12

MOA - blocks reabsorption of Na+/Cl- in early segment of distal convoluted tubule

• weaker diuretic than Loop ones
• can’t be used on pt w/renal impairment

Indications - 1st drug of choice in Rx of HTN (cheap drug)
- edema assoc. w/mild to mod HF, hepatic or renal disease

SEs - hypokalemia, FVD (hyponatremia, hypochloremia, dehydration)

NI - monitor K+ levels, weigh pt

Drug interactions - same as Furosemide w/Digoxin

Question 13

Potassium-sparing diuretic

Answer 13

Spironolactone (Aldactone)

Question 14

Spironolactone (Aldactone)

Answer 14

Drug classification - aldosterone antagonist (potassium sparing diuretic)

MOA - block the action of aldosterone in distal tubule

• weak diuretic but ↓ K+ excretion
• commonly combined w/loop or Thiazide diuretic

Indications - HTN, edema, HF (↓ mortality and morbidity in HF pts)

Caution in combining w/: ACE inhibitors, salt subst (b/c have a lot of K+)

NI - monitor K+ levels; if get >5.0 - hold med & call dr.

Question 15

Osmotic diuretic

Answer 15

Mannitol (Osmitrol)

Question 16

Mannitol (Osmitrol)

Answer 16

MOA - promotes diuresis by creating osmotic force in the nephron

Strongest diuretic - not for HTN

Indications - to ↓ intracranial pressure (ICP) – pt w/crebral edema; prophylaxis of renal failure, ↓ of IOP

Route - IV only

Question 17

NI and pt education for diuretics

Answer 17

1. check K+ levels
2. monitor I/O status (daily wt)
3. baseline assessment (lung sounds)
4. know S/Sx of hypokalemia, hypochloremia, dehydration

Question 18

Spironolactone - SE

Answer 18

Potassium sparing diuretic

SE

• hyperkalemia (⇡ peak wave, change in EKG);
• endocrine effects (acts like a steroid) - may include menstrual irreg

Question 19

BiDil (Isosorbide Dinitrate and Hydralazine)

Answer 19

BiDil is a fixed-dose combination of isosorbide dinitrate plus hydralazine and it can be used for patients who cannot tolerate ACE inhibitors or ARBs. BiDil is approved specifically for treating heart failure in blacks.