Pharmacology Diuretics Quiz

Diuretics & Cardiac Drugs

• Diuretics increase urine output (diuresis)
• Normal urine output is 30 mL/hour or greater
• Normal GFR = 125 mL/hour
• Normal output = about 60 mL/hour
• Diuretics mainly affect maintenance of the extracellular fluid (ECF)

Furosemide (Lasix)

• Classification: Loop diuretic, potassium-wasting diuretic
• Mechanism of Action (MOA): Rapid-acting loop diuretic; inhibits sodium and chloride reabsorption in the ascending loop of Henle; decreases edema and blood pressure
• Uses: Very powerful diuretic, often used in acute situations or heart failure (CHF) to reduce fluid buildup
• Dosage/Route: PO, IV, IM; 20-80 mg; IV starts in 5 minutes, lasts for 2 hours
• Adverse effects: Postural hypotension, hypokalemia, hyponatremia, hypomagnesemia, hyperchloremia, nausea, vomiting, dehydration, tinnitus, aplastic anemia, circulatory collapse
• Drug interactions: Low potassium increases risk of digoxin toxicity; digoxin toxicity causes various cardiac dysrhythmias; combined with other ototoxic drugs (e.g., aminoglycosides) can cause hearing loss; combined with other antihypertensives or lithium may cause hypotension
• Patient education: Check potassium levels (3.5-5.0) before administration; check blood pressure before administration (>110/60); weigh daily to assess treatment effectiveness; inform patients about monitoring of symptoms during high volume diuresis, and to report any ineffective responses to their physician; advise patients to increase their dietary intake of potassium-rich foods/supplements.

Hydrochlorothiazide (HydroDIURIL)

• Classification: Thiazide diuretic, potassium-wasting diuretic
• MOA: Blocks sodium and chloride reabsorption in the early distal convoluted tubule; not effective if GFR is low (<15-20 ml/min).
• Uses: Often first-line treatment for hypertension, especially in African Americans; used in mild to moderate heart failure to help mobilize edema
• Dosage/Route: PO, dosage varies based on formulation
• Adverse effects: Hyponatremia, hypochloremia, dehydration, hypokalemia; fetal harm; can enter breast milk; may elevate glucose levels in diabetics; may precipitate gouty arthritis
• Drug interactions: Promotes digoxin toxicity due to potassium loss; increases risk of hypotension with other antihypertensive medications
• Patient education: Not given to pregnant or breastfeeding patients, diabetics, or those with gouty arthritis; monitor potassium, sodium, and chloride levels; increase potassium intake in diet/supplements

Mannitol (Osmitrol)

• Classification: Osmotic diuretic
• MOA: Creates an osmotic effect in the proximal convoluted tubule, inhibiting passive water reabsorption. Has no significant effect on potassium excretion.
• Uses: Preventing/reducing acute renal failure in severe hypertension, hypovolemic shock, reducing intracranial pressure (ICP), reducing intraocular pressure (IOP).
• Dosage/Route: IV infusion (hospital use only), Solutions are 5-25% (infusion percentage)/usually crystallized warmed in water initially frozen; IV infusion rate is adjusted to monitor urine flow rate, which is typically 30-50 mL/min. Measured with a hydrometer.
• Adverse effects: Headache, nausea, vomiting, electrolyte imbalance, pulmonary edema.
• Patient education: Not for home use, only administered in a clinical environment. Inform patients on risks/warnings and importance of reporting observations.

Spironolactone (Aldactone)

• Classification: Potassium-sparing diuretic (Aldosterone Antagonist)
• MOA: Blocks the action of aldosterone in the distal nephron, promoting sodium excretion and potassium retention.
• Uses: Hypertension, edema, heart failure.
• Adverse effects: Hyperkalemia (>5.0), resulting in fatal cardiac dysrhythmias (e.g., ventricular fibrillation). Has endocrine effects similar to steroid hormones (e.g., gynecomastia, irregular menses)
• Drug interactions: Caution with ACE inhibitors, ARBs, direct renin inhibitors.
• Patient education: Monitor potassium levels. Never administer with potassium-sparing drugs or salt substitutes, or ACE inhibitors or ARBs.

Triamterene (Dyrenium)

• Classification: Potassium-Sparing Diuretic (Non-Aldosterone Sparing)
• MOA: Disrupts sodium-potassium exchange directly in the distal nephron.
• Uses: Hypertension, edema. Counteracts the potassium-wasting effects of other diuretics.
• Adverse effects: Nausea, vomiting, leg cramps, dizziness, hyperkalemia
• Drug interactions: Caution with ACE inhibitors, ARBs, and direct renin inhibitors
• Patient Education: Monitor potassium levels, do not administer with other potassium-sparing medications, or salt substitutes.

Potassium Chloride (K+ Supplementation)

• Classification: Potassium Supplement
• MOA: Replacement of potassium for nerve impulse transmission
• Uses: Replaces potassium lost via other medications or conditions requiring potassium replacement.

Additional Information (from further pages)

• Potassium Removal: Symptoms of excess potassium can include confusion, anxiety, shortness of breath, heaviness/tingling in legs and hands, lips, and feet. Steps/treatments include holding potassium-containing foods/medications, infusion with calcium gluconate, insulin, sodium bicarbonate, exchange resin (such as Kayexalate).
• Oral Potassium Chloride(KCL): Irritates the GI tract, potentially severe intestinal ulcers, causing bleeding or perforation. Also causes hyperkalemia (excess potassium) which can cause cardiac dysrhythmias, ranging from mild to severe life-threatening issues.
• Potassium sparing Diuretics: Should be used with caution, with monitored potassium levels, and in conjunction with other potassium-sparing drugs or salt substitutes, and ACE inhibitors or ARBs.
• Blood Pressure Categories: Normal range is below 120/80.
• Misc. Antihypertensive Agents (e.g., atropine, prazosin, propranolol) and additional details are further described in subsequent sections.
• Numerous other drugs are discussed that relate to hypertension control, and their mechanism of action, adverse effects, etc, which are all mentioned in their designated sections on the subsequent pages.