Homestasis - Diuretics Flashcards
Thiazides
Synthetic diuretic drugs, chemically related to the sulfonamides and differ mainly in their duration of action. Drugs of choice for most patients who require diabetic therapy, especially long-term management of heart failure and hypertension.
Thiazide prototype drug
Hydrochlorothiazide
Hydrochlorothiazide
Prototype thiazide; most commonly used drug in the class; not a strong diuretic and works efficiently only when urine flow is adequate
Thiazide (Hydrochlorothiazide) action
Acts to decrease reabsorption of sodium, water, chloride, and bicarbonate in the distal convoluted tubule. (most sodium is reabsorbed before the distal convoluted tubule, so only a small amount is reabsorbed at the site.)
Thiazide (Hydrochlorothiazide) Use
Treatment of mild to moderate hypertension and the edema associated with heart failure and nephrotic syndrome. Effective for most patients.
Thiazide (Hydrochlorothiazide) for children
Hypertension, edema, bronchopulmonary dysplasia, hypercalciuria, and congenital nephrogenic diabetes insipidus. Chlorothiazide suspension may be preferred. Hydrochlorothiazide IV usually not recommended. Thiazides do not commonly cause hyperglycemia, hyperuricemia, or hypercalcemia in children, as they do in adults.
Thiazide (Hydrochlorothiazide) for Older Adults
Management of hypertension and heart failure. Older adults are especially sensitive to ADEs, such as hypotension and electrolyte imbalance. May aggravate renal or hepatic impairment. With rapid or excessive diuresis, MI, renal impairment, or cerebral thrombosis may occur from fluid volume depletion and hypotension. Smallest effective dose recommended. ADEs may exceed therapeutic effects at doses greater than 25 mg.
Thiazide (Hydrochlorothiazide) with renal impairment
May be useful in managing edema due to renal disorders such as nephrotic syndrome and acute glomerulonephritis. Effectiveness decreases as the GFR decreases, and is ineffective when the GFR is less than 30mL/min. Accumulation and increased ADEs with renal impairment. Requires periodic renal function tests.
Thiazide (Hydrochlorothiazide) with hepatic impairment
Significant risk for thiazide-induced hypokalemic and hypochloremic alkalosis (w/severe hepatic impairment). Hepatic encephalopathy and death have occurred because of electrolyte imbalances. Blood ammonia levels continuously rise in those with previously elevated blood ammonia. Cautious thiazide use with hepatic impairment and discontinuation if signs of impending hepatic coma (e.g. increased jaundice, tremors, confusion, asterixis) appear.
Thiazide (Hydrochlorothiazide) with critical illness
Ineffective for immediate diuresis due to SLOW ONSET OF ACTION. Loop diuretics (Furosemide/Lasix) are more likely to be administered in a critical care setting due to the need for increased potency.
Hydrochlorothiazide and general anesthesia
Hydrochlorothiazide should not be given the morning of surgery because it may lead to volume depletion, causing BP to be labile and undergo frequent changes with general anesthesia.
Thiazide (Hydrochlorothiazide) with home care
The nurse may need to assist patients and caregivers in drug safety, response monitoring, and providing information. Assessment of nutritional status, BP, weight, and OTC medications that may aggravate edema or hypertension.
Thiazide (Hydrochlorothiazide) ADEs
Hypersensitivity reactions, hypotension, weakness, dizziness, diarrhea, constipation, electrolyte imbalances (hyponatremia, hypokalemia, hypochloremia), hyperglycemia, paresthesia, and erectile dysfunction.
Thiazide (Hydrochlorothiazide) Contraindications
Known sensitivity to thiazides of sulfonamide-derived agents (cross-sensitivity) or renal decompensation or anuria (no urine output).
Thiazide (Hydrochlorothiazide) Interactions
Thiazides can increase the effects of ACE inhibitors, other antihypertensive, allopurinol, calcitriol, and lithium.
