diuretics

interstitial fluid increases by 2 1/2-3L

2mm, trace

4 mm, moderate-disappears in 10-15 seconds

6 mm, deep-disappears in 1-2 minutes

8 mm, very deep-disappears in 5 minutes

treat underlying cause, supportive treatment, sodium restriction, diuretics

first line for pts with edema secondary to DVT or overproduction of lymph fluid

• a. Avoid prolonged standing or inactivity
• b. Elevate edematous legs
• c. Avoid placing hard objects under the knees when reclining
• d. Avoid constricting clothing, including tight-fitting or high-heeled shoes
• e. Avoid alcohol and excessive heat
• f. Support hosiery

DASH diet <2400mg sodium, one tea NaCl tablet salt contains 2000 mg sodium

when edema persists despite supportive therapy and sodium restricted

• ex: acetazolamide
• Use:

• • Diuretic (rarely)
• • Glaucoma (↓ IOP)
• •Metabolic Alkalosis
• •Altitude Sickness

• ex: mannitol
• Use:

• • Diuretic (rarely)
• • Cerebral edema
• • ↓ Intracranial pressure

• most potent diuretic
• ex: bumetanide, furosemide, torsemide
• use:

• • Diuretic
• • Hypercalcemia
• • Pulmonary Edema
• • RTA

• moderate diuretic activity
• ex: chlorothiaz, HCTZ, chlorthal, indapamide, metolazone
• use:

• • Diuretic
• • Hypertension
• • Hypercalciuria
• • Diabetes insipidus

• least potent
• ex: amiloride, triamterene, spironolactone, eplerenone
• use:

• • Diuretic
• • K loss
• • Cirrhotic ascites
• • CHF (spironolactone, eplerenone

• loops and thiazides
• associated with: dose, worse with long-acting, high sodium intake

• 1. use smallest dose poss
• 2.restrict Na
• 3. encourage k-rich foods ( can prevent but not treat if metabolic alkalosis K citrate in foods is converted to bicarb
• 4. subst or add k-sparin
• 5. recomm a salt subst 10 mEq K/gm
• 6.rx an oral k supp 20 mEq/day
• 7. add an ACE or ARB

• **PO is 2x the IV dose
• a. F varies with product
• • Toresemide (Demedex ®) ~80-100%
• • Bumetanide (Bumex ®, generics) ~80-90%
• • Furosemide (Lasix ®, generics) ~10-100% (50%)
• b. Duration of Action – 2-3 hours
• c. High Ceiling Effect
• d. Dosing: Start with 20 mg furosemide PO (or equivalent). If inadequate response, double the dose
• sequentially until response ensues or max dose reached.

40 mg furosemide IV=80 mg PO

furosemide-doses greater than or equal to 100 mg IV, rapid inf time and worse with other drugs causing ototox, AGs and vanco

4mg/min

6-12 hours chlorthiazide, HCTZ

12-24 hours, metolozone

>24 hours, chlorthaiidone, indapamide

• loop-high ceiling effect
• thiazides-low

• a. ineffective when CrCl <30ml/min
• b.Hyponatremia -part. in elderly
• c.Hyperuricemia -also with loops but worse
• d.Hypercalcemia (rarely) -calcium-sparing, good for post-menopausal
• e.Hyperglycemia -still first line in HTN
• f. ↑ Serum Lithium levels • Pancreatitis

• aldosterone antag
• plateu effect not reached til 3-4 days
• dose 25-100 mg qd x 5 days, titrate up to 200mg/day

Inspra

• Selective Aldosterone antagonist
• • Plateau effect – max effect not seen for 4 weeks
• ¾ Dose: 25 mg q day x 4 weeks. Titrate upwards to 100 mg daily

• Dyrenium,
• (+ HCTZ = Dyazide ® 37.5 /25 & 50/25 , Maxide -25® 37.5/25
• Maxide ® 75/50 )
• d. Amiloride (Midamor ® )
• e. Specific Clinical Concerns
• ¾ Hyperkalemia
• ¾ Hyponatremia (spironolactone, eplerenone)
• ¾ Gynecomastia (spironolactone)
• ¾ Nephrolithiasis & Nephrocalcinosis (triamterene)

• a. Na restriction-cornerstone, Na overrides effect of diuretic
• b. Avoid drugs that interfere with diuretic effectiveness
• c. Dose -short-acting max diuresis within a few hours, can increased.
• d. Route-HF Gi abs decreased due to excess fluid in gut, take on empty stomach, or switch to higher F or continous IV

• rate of diuresis:
• -initial fluid loss-intravascular space-refilled by fluid mobilized in interstium, rate should not exceed rate of mobilization or will be hemodynamically unstable, goal: 1-2 lbs/24 hours, except ascites assoc with cirrhosis, slower movement more gradual 0.5-1 lbs/day

• vitalsigns
• • Weight
• • BUN:Cr ratio (~ 10-20:1)
• • GFR
• • Potassium

Failure to ↓ interstitial fluid volume despite liberal use of diuretics and sodium restriction

• -nephron adaptation to chronic therapy
• • Drugs (NSAIDs) Potential solutions
• • Sequential nephron blockade
• • DC offending agents

• due to drugs (NSAIDs)
• potential soln
• d/c offending agents

increase dose or more freq admin or cont infusion

to maintain threshold conc at all times, can see increase with same dose

• Sample protocols – most suggest a bolus dose of 40-80 mg IV furosemide followed by continuous
• infusion furosemide 250 mg in 250cc D5W @:
• • 0.05 – 0.1 mg / Kg / hr – titrate ↑ to goal UOP (CHF 2002;8(2):80-85) -or -
• • Start @ 0.1 mg/Kg/hr - ↑ hourly by 0.1 mg/kg/hr to a max rate of 0.75 mg/kg/hr (Crit Care Med
• 1997;25:1969-1975) - or -
• • NEJM 1998;339(6):387-395
• J. Diuretic Challenges
• 1. Ascites associated with cirrhosis
• a. Diuretic

• -diuretic challenges:
• • Secondary hyperaldosteronism causes sodium & water retention
• • Rapid diuresis may compromise intravascular volume
• • ↓ renal tubular responsiveness to diuretics b. Therapeutic Approach
• • Spironolactone 100-200 mg / day administered with food
• • If inadequate response, add low dose Metolozone or Indapamide prn

• -diuretic challenges:
• • Impaired oral absorption of furosemide
• • ↓ renal tubular responsiveness to diuretics b. Therapeutic Approach
• • Give moderate doses of loop diuretic more frequently
• • If inadequate response, add a thiazide in doses appropriate for renal function

• -diuretic challenges:
• • Impaired delivery of diuretic to renal tubule
• • ↓ filtered load of sodium in response to ↓ GFR b. Therapeutic Approach
• • Give increasing doses of loop diuretic up to 160-200 mg furosemide IV bolus (or equivalent)
• • If inadequate response, add Metolazone or Indapamide
• • If diuresis still inadequate, continuous infusion of loop diuretic

• >3gm, protein spills into urine
• a. Diuretic Challenges
• • Impaired delivery of diuretic to renal tubules secondary to binding to urinary protein
• • ↓ renal tubular responsiveness to loop diuretics
• • ↑ proximal or distal reabsorption of sodium
• b. Therapeutic Approach
• • Give larger doses (2-3 x normal) of loop diuretic
• • Administer diuretic more frequently
• • If inadequate response, add thiazide

• diuretics less effective for treating
• recommend alternatives to drugs that are causing the edema