Pharm - Diuretics + Potassium

types of diuretics

loop

thiazide

osmotic

potassium sparing

diuretic

increases urine output

normal output = 30mL/hr+

mainly affect maintenance of ECF

Loop diuretic prototype

Furosemide (Lasix)

thiazide diuretic prototype

hydrochlorothiazide

osmotic diuretic prototype

Mannitol

potassium sparing diuretic prototype

Spironolactone (Aldactone)

Furosemide (Lasix): indications

-given for massive movement of fluids

-given for acute and chronic heart failure

-not first choice, try to start w thiazide

Furosemide (Lasix): MOA

rapid acting loop diuretics

inhibits Na and Cl reabsorption in ascending loop of henle

Furosemide (Lasix): T/A

decrease edema, decrease BP

Furosemide (Lasix): A/E

-postural hypotension

-hypokalemia/natremi/chloremia

-N/V

-dehydration

-tinnitus (can lead to hearing loss)

-circulatory collapse (body fails to deliver O2 & nutrients to tissues)(if given IV)

Furosemide (Lasix): NI

-check potassium before admin

-check BP (at least 110/60)

-daily weight

-monitor pt for hypotension during high volume diuresis

-rapid IV admin can cause cardiac arrest

-ECG monitoring

Furosemide (Lasix): dose + route

oral, IV, IM

20-80mg

IV action begins in 5 min + lasts for 2 hours

Furosemide (Lasix) D/I

if potassium is low, high risk for drug toxicity

digoxin toxicity = dysrhythmias

hearing loss w/ other ototoxic drugs

lithium = high sodium

antihypertensives = hypotension

Hydrochlorothiazide (hydrodiuril)

thiazide diuretic

Hydrochlorothiazide (hydrodiuril): MOA

blocks reabsorption of Na and Cl in early segment of the DCT

Hydrochlorothiazide (hydrodiuril): Indications

-HTN, 1# drug choice for black ppl

-mild to mod heart failure

-mobilize edema associated w hepatic/renal dz

Hydrochlorothiazide (hydrodiuril): considerations

drug is not effective if GFR is < 15-20

Hydrochlorothiazide (hydrodiuril): A/E

-hyponatremia

-hypochloremia

-hypokalemia

-dehydration

can cross placenta, can enter breast milk

Diabetes (elevates glucose)

Precipitate gouty arthritis

Hydrochlorothiazide (hydrodiuril): D/I

-promote digoxin toxicity d/t potassium loss

-incr. effects of hypotension when taken w other antihypertensives

Hydrochlorothiazide (hydrodiuril): route

oral

mannitol (osmitrol)

osmotic diuretic

mannitol (osmitrol): MOA

creates osmotic action that inhibits passive reabsorption of water in the PCT.

NO effect on K+ excretion

mannitol (osmitrol): indications

-prevent/slow onset of renal failure

-severe hypotension

-hypovolemic shock

-reduction of ICP & IOP

mannitol (osmitrol): A/E

-HA, N/V

-electrolyte imbalance

-pulmonary edema

-congestive heart failure

mannitol (osmitrol): administration

solutions are 5-25%

usually crystallized

warm in water first

administer per IV infusion to obtain urine flow rate of 30-50mL

potassium sparing diuretic categories

-aldosterone antagonists: spironolactone

-nonaldosterone antagonists: triamterine, amiloride

Spironolactone (Aldactone)

potassium sparing diuretic - prototype

aldosterone antagonist

Spironolactone (Aldactone): MOA

blocks action of aldosterone in the distal nephron

inhibition of aldosterone causes retention of K and excretion of Na & water

Spironolactone (Aldactone): A/E

-Hyperkalemia (can result in fatal cardiac dysrhythmias such as V-Fib).

-Gynnecomastia: swollen male breast tissue by hormone imbalance

-Menstrual irregularities

Triamterine (Dyrenium)

nonaldosterone sparing diuretic

Amiloride: MOA & A/E

Inhibit potassium loss by direct blockade of sodium to potassium exchange in the distal nephron.

Hyperkalemia

Amilorade: Indication

To counteract the potassium laws caused by more powerful diuretics (Thiazides, loop diuretics)

Potassium chloride

K Supplement

MOA: replacement

Potassium chloride: nursing implications

IV only

no faster than 10mEq in 100mL per hr

IV drip NEVER push

dilute 10mEq in 100mL (ICU)

40mEq/500-1000mL

check potassium level before each dose

ways potassium is lost

• Vomiting

• Diarrhea

• Prolonged diuresis

• Insufficient intake of K+

• Alkalosis

• Excessive insulin

potassium chloride PO

large pills, take w water and pt sitting up

liquid form dilute in orange juice

potassium chloride: adverse effects

-GI tract irritation: abd. pain, N/V, diarrhea

-large pills can cause severe intestinal ulcers

removal of excess potassium

1. withhold potassium containing foods/meds

2. infuse calcium gluconate

3. infuse insulin and glucose to push K+ intracellularly

4. infuse sodium bicarb to increase pH and cellular intake of K+

5. give oral or enema Kayexalate an exchange resin that removes K+

6. peritoneal or hemodialysis to remove K+

the closer a diuretic works at the glomerular filtration center (bowmans capsule)....

the more effective it is

recommended furosemide IV admin time

20mg/min

5mg/15seconds

Mannitol indications

hypertension

heart failure

primary aldosteronism

Triamterene (Dyrenium): MOA

potassium sparing diuretic

disrupts sodium-potassium exchange directly in distal nephron

spironolactone works over days while triamterene works over..

hours

Spironolactone (Aldactone): indications

hypertension

edema

usually given in combination w loop diuretic or thiazide

Spironolactone (Aldactone): NI

never give w potassium, salt substitutes, or other K+ sparing drugs

How to reduce hyperkalemia

give insulin IV

Triamterene indications

-hypertension

-edema

mainly used to counteract potassium wasting effects of lasix

Triamterene: A/E

-N/V (common)

-leg cramps

-dizziness

-hyperkalemia

Triamterene: cautions

use caution if combining with:

-ACE inhibitors

-ARBS

-direct renin inhibitors