PC707 Exam 4 Cardiac Questions With Accurate Answers
Thiazide diuretics
Hydrochlorothiazide (Hydrodiuril)
Chlorthalidone
Indication:
Essential HTN
Edema
Diabetes Insipidus
MOA:
- These agents work by reducing blood volume & reducing arterial resistance
- They promote potassium, sodium & water excretion by inhibiting Na & Cl reabsorption
in the early segment of the distal convoluted terminal of the nephron
- Diuresis is considerably less than with loop diuretics
- Not effective when urine flow is scant (unlike with loop diuretics)
Peak effects occur in 4-6 hours
The most widely used diuretic
These may be used in the management of HF patients. They are more effective in HF
than aldosterone antagonist diuretics but not as effective as loop diuretics.
s
Safety/Contraindication/D2D Interactions:
Hypokalemia, hyponatremia, hypochloremia, hypomagnesaemia
Hyperglycemia [DM], hyperuricemia [gout] r/t uric acid levels, hypercalcemia,
Postural hypotension
D2D: Digoxin, Can reduce renal excretion of Lithium, NSAIDs may blunt diuretic effects,
Caution with certain Sulfa drugs but sulfonamides are OK
- This one is OK to use with ototoxic drugs w/o increased risk of hearing loss
,- Dehydration
- Increased LDL, Triglycerides, and decreased HDL
Special Considerations:
- May help w/ bone loss in postmenopausal women because of calcium sparing effects
and they stimulate osteoblast activity
- Acts well as an add-on medication
- If taken with an ACEI, there is better K+ balance
- Do not administer to patients with severe renal disease because of hypokalemia
- Instruct the patient about the signs of electrolyte imbalances like dryness of mouth,
thirst, fatigue, weakness, lethargy, somnolence, restlessness, confusion, seizures,
cramping or muscle aches, hypotension, and GI disturbances like nausea and vomiting.
Not effective when the flow of urine is scant unlike in the case of loop diuretics
Have pt be on a high potassium diet.
Now, let's discuss about loop diuretics
Furosemide Lasix
Indications
Pulmonary edema
Edema of cardiac HE, hepatic, or renal origin
HTN unresponsive to other classes of diuretics
MOA
Inhibits the Na-K-Cl pump in kidneys & inhibit the reabsorption of Na & Cl in the loop of
Henle & in the proximal & distal tubule
More powerful than thiazide diuretics
They act even if low GFR
Safety/ contraindications/D2D:
Hypokalemia, hyponatremia, hypochloremia, [Dehydration], hypomagnesaemia
hyperuricemia [gout], hyperglycemia [DM], hypercalcemia, and LDL/ total chol, and HDL
Postural hypotension
Ototoxicity (temporary in furosemide; permanent with ethacrynic acid)
,D2D: Digoxin ((hypokalemia and toxic arrhythmias), lithium, ototoxic drugs, NSAIDs,
K-sparing drugs(above), other antihypertensive agents( hypotension)
Black Box Warning:
Produces profound diuresis and electrolyte depletion
Special
Fluid & electrolyte loss is of most concern
Monitor electrolytes, BP
Add PO KCl when indicated
Instruct slow transition from lying > sitting > standing
Avoid use in anuric patients
HF Specific Info:
Diuresis decreases CVP, right and left ventricular filling pressures, and pulmonary
vascular pressure.
Discuss Aldosterone Receptor Antagonists
OR Potassium-Sparing Diuretics
Spironolactone or Eplerenone (Inspra)
(aldosterone antagonist)
Triamterene or Amiloride
(non-aldosterone antagonists)
Indications:
, HTN, Edema, HF, PCOS, premenstrual syndrome, Primary hyperaldosteronism
MOA:
Spironolactone: Spironolactone-blocks aldosterone receptors in the distal nephron
causing retention of K and increased excretion of Na (slow onset, 1-2 days), a modest
increase in urine production
Triamterene: direct inhibition of Na & K exchange in distal nephron (onset in hours).
Decreases Na reuptake, inhibits ion transport
Safety/contraindications/D2D:
- They bind to the receptors for other steroid hormones, including glucocorticoids,
progesterone, & androgens leading to gynecomastia, impotence, hirsutism, deep voice,
irregular menstruation
- Hyperkalemia [ACEIs, ARBs, KCL]
- May cause benign or malignant tumors in rats
- D2D: Thiazide & loop diuretics (great in combination to balance K+). Agents that raise
the potassium level (Don't do it)
Special:
· Spironolactone or eplerenone: decrease mortality & hospital admissions in HF.
· Monitor electrolytes. They may be combined with a loop or thiazide diuretics to offset
K+ loss