Drugs for Cardiac - Diuretics Flashcards
hypertension (what is it?)
chronic progressive disorder that damages walls of blood vessels –> hypertrophy/hyperplasia of vessel lining –> causes target organ damage
- asymptomatic until long after injury
Primary (essential) HTN
- has no identifiable cause
Secondary HTN
- HTN is secondary to another disease
- not as common as primary
Therapeutic goals: HTN
- keep BP < 140/90 (keep even lower w/diabetes Mellitus and CHD)
- drug therapy and minimize drug side effects
- lifestyle modifications
- individualized therapy
types of drugs for HTN
- diuretics
- drugs that act on sympathetic NS
- drugs that act on RAAS
- calcium channel blockers (CCB)
- vasodilators
Diuretics
- MOA - block Na+ and H20 reabsorption –> ⇡ excretion of solute and water (& Cl-)
- “High ceiling” effects - drugs that act on a part of the nephron that blocks the largest amt of solute reabsorption
- Indications: HTN, HF, CKD
Loop diuretics
- for HTN
- act on the Loop of Henle (20%) of reabsorption takes place there
- Furosemide (Lasix)
- Bumetanide (Bumex) - 40x stronger than Furosemide
Furosemide (Lasix)
[also, Bumetanide (Bumex) = 40x stronger)
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)
SE of Furosemide (Lasix)
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)
5 major categories of diuretics
- loop diuretics
- thiazide diuretics
- osmotic diuretics
- potassium-sparing diuretics
- aldosterone antagonists
- nonaldosterone antagonists
- carbonic anhydrase inhibitors - used primarily to ↓ IOP (not to ⇡ urine output)
Drug interactions w/Furosemide
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
Thiazides
aka Hydrochlorothiazide / HCTZ
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
Potassium-sparing diuretic
Spironolactone (Aldactone)
Spironolactone (Aldactone)
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.
Osmotic diuretic
Mannitol (Osmitrol)
Mannitol (Osmitrol)
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
NI and pt education for diuretics
- check K+ levels
- monitor I/O status (daily wt)
- baseline assessment (lung sounds)
- know S/Sx of hypokalemia, hypochloremia, dehydration
Spironolactone - SE
Potassium sparing diuretic
SE
- hyperkalemia (⇡ peak wave, change in EKG);
- endocrine effects (acts like a steroid) - may include menstrual irreg
BiDil (Isosorbide Dinitrate and Hydralazine)
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.
