Diuretics Flashcards
Loop diuretics: Action
Action – these are the most potent diuretics available.
They inhibit Na+ and Cl- resorption in renal tubules by direct action on the ascending loop of Henle.
They also inhibit Na+, Cl- and water resorption in proximal tubule.
And they increase the concentrations of renal prostaglandins → dilation of blood vessels in the kidneys, lungs.
Loop Diuretics: Uses
Uses – Edema associated with HF, liver, and kidney disease; hypertension, hypercalcemia (often seen in CA patients).
Loop Diuretics: Side Effects
SE –
Volume depletion [esp in elderly],
orthostatic hypotension,
electrolyte disturbances (esp hypokalemia), tinnitus, transient deafness,
impaired glucose tolerance,
blood dyscrasia,
Steven-Johnson syndrome (awful skin problems which can lead to toxic epidermal necrolysis where your skin falls off). Neurotoxic (hearing loss is one sign) and nephrotoxic effects.
Loop Diuretics: Interactions
Interactions –
additive neurotoxic and nephrotoxic effects, increase serum uric acid, glucose, AST, ALT. Interacts with digoxin. Also, consistent NSAIDs use → less diuresis.
Loop Diuretics: Drugs
Drugs – furosemide [Lasix]** – related to sulfa drugs., po, IV. Also → loss of magnesium and calcium.
Bumetanide [bumex]
Ethacrynate [Edecrin]* – can cause irreversible ototoxicity
Torsemide [Demadex]*
Loop Diuretics: Nursing considerations
Nursing considerations – same as above plus: give IV slowly, over 4 minutes Fast administration can → transient tinnitus or deafness. Store in light resistant containers. These pts often need K+ supplements.
Thiazide Diuretics: Action
Action – sulfa drugs –
Inhibit tubular resorption of Na+ and Cl- ions in the ascending loop of Henle and distal tubule.
These are nowhere near as strong as the loop diuretics.
Thus, water, Na+, and Cl- are excreted. Also K+.
Also may increase GFR.
At first the decrease in blood volume decreases CO, but after a while, this stabilizes.
These drugs are most effective after 3-4 weeks of Tx.
Thiazide Diuretics: Uses
Uses – Hypertension (should be the first line, but aren’t?), edema, hypercalciuria, diabetes insipidus, HF, cirrhosis
Thiazide Diuretics: Side effects
SE – Orthostatic hypotension, hyponatremia, hypokalemia, glucose intolerance, GI, rash, HA, impotence, deceased libido.
Thiazide Diuretics: Interactions
Interactions – Digoxin (causes toxicity). Oral hypoglycemics – reduced effect – check BS.
Bile acid sequestrants – You need separate administration of these 2 classes.
Thiazide Diuretics: Drugs
Drugs – hydrochlorothiazide [HCTZ, Hydro-Diuiril, Esidrix]** -has diuretic ceiling effect at about 50 mg.
chlorothiazide [Diuril]
chlorthalidone [Hygroton]*
indapamide [Lozol]*
Thiazide Diuretics: Nursing Considerations
Nursing considerations – Check K+ and look for sxs of hypokalemia. Give K+ supplements. Check blood sugar. Weigh daily. Get up slowly. Give in AM. Check for sulfa allergy.
Potassium sparing diuretics: ACTION
Action – Na+ ion channel inhibitors have direct action on distal renal tubules - inhibits Na resorption → excretion of Na+ and water, and retention of K+.
Overall Mechanism of Action
- Work in collecting ducts and distal convoluted tubules.
- Interfere with sodium-potassium exchange.
- Competitively bind to aldosterone receptors
- Block the resorption of sodium and water usually induced by aldosterone.
Potassium sparing diuretics: USES
Uses – Hypertension; with other diuretics to prevent K+ loss.
Potassium sparing diuretics: SIDE EFFECTS
SE – hyperkalemia, anemia, dizziness, orthostatic hypotension, sore throat, dry mouth, N/V, irreg menses, kidney stones, impotence, hirsutism
