Hyper-Hypokalemia Drugs (Wolff) Flashcards
Hypokalemia on ECG
flattened t waves
tall u waves
ST segment depression
prolonged QT interval
Hyperkalemia on ECG
tall/peaked t waves
prolonged PR interval
widened QRS interval
flattened p waves
(can produce bradycardia**)
K+ sparing diuretics
spironolactone, triamterene and amiloride (Na+ ch blockers)
K+ losing diuretics
thiazides (Na/Cl cotransporter blocker)
loop diuretics (Na/K/2Cl cotransporter blocker)
carbonic anhydrase inhibitor
osmotic diuretics
Furosemide
directly inhibits reabsorption of NaCl by blocking Na/K/2Cl cotransporter; indicated in edema, pulm. edema, HTN; works in pts with low GFR
Torsemide
similar to furosemide; longer half-life; better oral absorption and has been seen to work better in heart failure
Bumetanide
similar to furosemide; more predictable oral absorption
Ethacrynic acid
non-sulfonamide loop diuretic reserved for those with sulfa allergy
MOA of loop diuretics
K+ losing diuretic that blocks the Na/K/2Cl co-transporter in the thick ascending limb
Hydrochlorothiazide (HCTZ)
K+ losing diuretic that inhibits Na reabsorption in distal tubule by blocking Na/Cl co-transporter; indicated in HTN; not effective in patients with low GFR
Chlorothiazide
similar to HCTZ but poor oral absorption
Chlorothalidone
similar to HCTZ; prolonged/stable response with HTN
Metolazone
another long-acting thiazide diuretic, favorite of cardiologist for use as adjunct in treatment in CHF
MOA of thiazides
block Na/Cl co-transporter in DCT
Amiloride
K+ sparing diuretic that block ENaC channels in the collecting duct; counteracts K+ loss; toxicity of HYPERkalemia
Trimterene
similar to amiloride; indicated in edema and off-label for HTN
Spironolactone
K+ sparing diuretic that is a competitive antagonist of aldosterone receptors; also a partial agonist for androgen receptors; indicated off-label to reduce fibrosis post-MI failure; slow on and slow off pharmacokinetics; toxicity is HYPERkalemia
Eplerenone
more selective aldosterone antagonist than spironolactone; approved for use in post-MI heart failure and HTN
Treatment for hypokalemia
replace K+ deficit; if severe IV K+ (potassium chloride or potassium acetate) if not oral K+
Treatment for hyperkalemia
Emergency management (3): 1. antagonize cardiac effects (give IV calcium) 2. redistribute K+ into cells (IV insulin and glucose) 3. Facilitate K+ elimination (K+ losing diuretic - furosemide)
Hyperkalemia signs and symptoms
Cardiac (bradycardia, peaked t wave, widened QRS complex) and Neuromuscular (numbness, weakness, flaccid paralysis)
Hypokalemia signs and symptoms
CNS (drowsiness, lethargy), Neuromuscular* (most prominent manifestation) - skeletal muscle weakness and smooth muscle weakness (constipation), CV (hypotension, cardiac arrest), Renal (polyuria, nocturia), Metabolic (HYPERglycemia)
Alternative Medicine
Herbal diuretics - active ingredients and MOA are generally unknown; should not be mixed with conventional diuretics
Licorice - contains glycyrrhizic acid
MOA K+ sparing diuretics
amiloride- blocks Na ch (ENaC) in collecting ducts
spironolactone - blocks aldosterone receptor in collecting duct
Toxicity of furosemide
HYPOkalemia, HYPOnatremia, HYPOcalcemia, HYPOmagnesemia, HYPOchloremic
HYPERglycemia and HYPERuricemia
Ototoxicity (tinnitus); risk for sulfonamide hypersensitivity
What drug is not effective in patients with low GFR?
Hydrochlorothiazide (HCTZ); K+ losing diuretic
Toxicity of Hydrochlorothiazide (HCTZ)
HYPOkalemia, HYPOnatremia, HYPOmagnesemia, HYPOchloremic
HYPERglycemia and HYPERuricemia
HYPERcalcemia (differs from furosemide)
sulfa drug (hypersensitivity)
