NCLEX Quick Review of Diuretic Medications


(General Key Points)

This is part one – we’ll be reviewing Diuretics. Next week we’ll post about minerals and renal.

Enjoy your weekend.

Some highlights.

Diuretics increase fluid loss via urine output

Major uses of diuretics include prevention of renal failure and management of hypertension.

Most diuretics work by blocking reabsorption of Na+ and Cl; the more ion absorption blocked, the more fluid that is lost.

Potassium is necessary for nerve impulse conduction and regulation of acid-base balance.

Calcium is critical to normal metabolic processes of the heart, nerves, muscles, bones, and coagulation.

Mineral supplements tend to cause GI distress and should be administered with a full glass of water or with meals.


High Ceiling Loop Diuretics

Expected Action:

In upper Loop of Henle to block reabsorption of Na+/Cl/H2O leads to Extensive diuresis.

Example: furosemide (Lasix) — Others: ethacrynic acid (Edcrin), bumetanide (Bumex), Torsemide (Demadex)

Therapeutic Uses: Pulmonary edema d/t heart failure, Works well with renal impairment, Hypercalcemia r/t stone formation, Reserved for conditions unresponsive to other diuretics (e.g. edema d/t liver, cardiac or renal disease; hypertension)

Adverse Effects:

Dehydration (notify physician output < 30 mL/hr)
Ototoxic – furosemide (temp); ethacrynic acid (permanent) – no other ototoxics
Hyperglycemia, hyperuricemia, decreases [Ca2+], [Mg2+]

Contraindications/Precautions: Pregnancy (C), Caution ĉ diabetes, gout

Interactions: Digoxin toxicity r/t decreased K+, NSAIDs blunt diuretic effect, Antihypertensives – Additive hypotensive effect, [Li] increases d/t diuresis


  • Daily weights, infuse slowly (20 mg/min), increase K+ foods (avocado, strawberry, banana, potato, spinach, tomato, meat, carrots), decreased Mg2+ signs: muscle twitch and tremor


Thiazide Diuretics

Expected Action:

In early DCT to block Na+/Cl/H2O reabsorption – promote diuresis when renal function is not impaired.

hydrochlorothiazide (HydroDIURIL) — Others: chlorothiazide (Diuril), indapamide

Therapeutic Uses:

1st choice essential hypertension, Edema of mild-to-moderate heart failure and liver/kidney disease.

Contraindications/Precautions: Pregnancy (B), NO breastfeeding, Caution ĉ renal impairment – may not be effective


Digoxin toxicity d/t decreasedK+, Antihypertensives: Additive effect, increased lithium levels, NSAIDs blunt diuretic effect


Alternate day dosing can decrease electrolyte imbalances
Increased K+ foods (avocado, strawberry, banana, potato, spinach, tomato, meat)


K+-Sparing Diuretics

Expected Action:

Block aldosterone action resulting in K+ retention and Na+/H2O excretion.

Example: spironolactone (Aldactone) — Others: triamterene (Dyrenium), amiloride (Midamore)

Therapeutic Uses: Combined with other diuretics for K+-sparing effect, Blocks aldosterone in hyperaldosteronism, Heart failure

Adverse Effects:

Hyperkalemia (insulin injection drives K+ back into cell)
Endocrine effects: Irregular menses or impotence


ACE inhibitors (lisinopril) leads to increased hyperkalemia
K+ supplements leads to increased hyperkalemia


Triamterene may color urine blue


Osmotic Diuretics

Expected Action:

Increases blood osmolality thus attracting fluid (e.g. 3rd spacing, CSF, intraocular)

Examples: mannitol (Osmitrol) — Others: urea, glycerin, isosorbide

Therapeutic Uses:

Decreases ICP, Decreases intraocular pressure (IOP), Prevent renal failure in hypovolemic shock or severe hypotension., Promote Na+ retention and H2O excretion in hyponatremia and fluid V excess

Adverse Effects:

Heart failure / pulmonary edema
Renal failure (urine < 30 mL/hr, creatinine > 1.2 mg/dL, BUN > 20 mg/dL
Fluid and electrolyte imbalance


Lasix complements through renal excretion of fluid drawn by osmotics.


Most effective given as a bolus, Use filter to prevent crystals, Monitor serum osmolarity and every 6 hours / urine osmolarity daily


Past Medication posts –

Respiratory Meds –

Blood –


Nervous System Meds (4 parts)


Cardiac Medications

Part 1 –
Part 2 –
Part 3-

Pain Meds and Inflammation –

Immunity and Chemo –

Anti Infective Drugs –

More information can be found on our blog –

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