Pharm Exam 1 (diuretics)

What do Diuretics do?

* ↑ urine output
* helps you pee

Therapeutic Use for Diuretics

* hypertension (↓ resistance = ↓ stroke vol)
* mobilization of fluid
* heart failure
* cirrhosis
* kidney disease
* prevent renal failure

What are the Basic Functions of the Kidney?

* maintenance of acid-base
* cleansing of extracellular fluid
* maintenance of ECF volume & composition
* excretion of metabolic wastes & foreign substances

What is the Basic Renal Process?

* filtration
* reabsorption (electrolytes)
* active sedation

Filtration

* small molecules in plasma are filtered
* ex: Na, Cl, HCO3, K
* large molecules stay in the blood
* ex: lipids & proteins

Reabsorption

* >99% of water, electrolytes & nutrients are reabsorbed
* occurs through active transport
* H2O follows passively due to osmotic gradient

MOST DIURETICS ACT BY INTERFERING W/ REABSORPTION

sodium potassium exchange

* aldosterone stimulates reabsorption of sodium from distal nephron & causes potassium to be excreted

How do diuretics work?

* causes a blockade of Na & Cl reabsorption
* creates osmotic pressure that PREVENTS passive water reabsorption

Classifications of Diuretics

* high-celing (LOOP) diuretics
* thiazide
* osmotic
* Potassium Sparing
* aldosterone antagonists
* non-aldosterone antagonists

Loop Diuretics

1st GO TO, TO GET RID OF FLUID

* most EFFECTIVE
* Produce more loss of F & E
* Prototype: Furosemide (Lasix)
* get rids of electrolytes (Na, K)

Furosemide (Lasix)

* Mechanism of Action

blocks reabsorption of Na+ & Cl-

Furosemide (Lasix)

* Administration

PO, IV, IM

Furosemide (Lasix)

* PO Administration

* works in 60 min
* lasts 8 hrs
* med makes PT have to pee → so take in the morning

Furosemide (Lasix)

* IV Administration

* works in 5 min
* lasts for 2 hrs
* give SLOW ,over 2-2 min IV push
* 4mg/min for continuous infusion

Furosemide (Lasix)

* pharmacokinetics

* metabolized in liver
* renal excretion

Furosemide (Lasix)

* Therapeutic uses

* pulmonary edema
* CHF
* edema of hepatic, cardiac, or renal
* HTN
* sever renal impairment (low GFR)

What can you add to Furosemide (Lasix) treatment if it isnt working?

add thiazide if treatment is not sufficient

Furosemide (Lasix)

* Adverse Effects

* electrolyte imbalance
* dehydration
* ototoxicity
* hyperglycemia
* hyperuricemia (gout)

Furosemide (Lasix)

* Drug interactions

* Digoxin
* Lithium
* Ototoxic
* potassium sparring diuetics

Furosemide (Lasix) & Digoxin (Lanoxin)

*  ↓ K+ = dig toxicity
* ↑ arrhythmias in hypokalemia
* ↑ K+ = less dig working

Furosemide (Lasix) & Lithium

↑ toxicity in hyponatremia (↓Na+)

Furosemide (Lasix) & Ototoxic Drugs

↑ risk for hearing loss if used concurrently

Furosemide (Lasix) & K+ Sparring Diuretics

reduces risk of hypokalemia

Furosemide (Lasix) & Pregnancy

Category C → can cause maternal death/abortion/fetal reabsorption

Furosemide (Lasix) & Lactation

May ↓ breast milk production

Furosemide (Lasix) & Peds

same side effect profile as adults

Furosemide (Lasix) & Gero

↑ risk for drug interactions (polypharmacy)

* dehydration, hypotension, heart arrhythmia,fall risk

Furosemide (Lasix) Nurs. Consideration

* s/s of dehydration

* dry mouth


* unusual thirst
* oliguria
* dizziness
* postural hypotension

Furosemide (Lasix) Nurs. Consideration

* ↑ risk of thrombosis & embolism
* s/s?

lack of vol in vasculature = thrombus formation

* s/s
* angina, pain in calves or pelvis, HA

Furosemide (Lasix) Nurs. Consideration

* Assess Fluid Status

* vitals (BP & HR)
* I & O
* weight
* ex: for heart failure patients → report >3lbs to Dr

Furosemide (Lasix) Nurs. Consideration

* Labs to assess

* kidney function
* creatinine, BUN, GFR
* electrolytes
* K+, Na+, Cl-, Mg+
* Serum lithium & digoxin levels (to make sure PT is NOT toxic)

Furosemide (Lasix) Nurs. Consideration

* PT Teaching

* educate about high K+ diet
* dried fruit, nuts, spinach, citrus, potatoes, bananas, non-sodium table salt
* Have PT notify provider if urine output drops

Thiazide Diuretics

* Mechanism of Action

* ↑renal excretion of Na+, K+, water, Cl-
* promote reabsorption of Ca+
* ↑ glucose & uric acid levels

NEED A GOOD GFR TO USE

KIDNEYS MUST WORK

Hydrochlorothiazide (HCTZ)

1ST CHOICE FOR HYPERTENSION

* weak diuretic effect because MOST of the Na+ is reabsorbed

Hydrochlorothiazide (HCTZ)

* Therapeutic Uses

* Hypertension
* preferred drug for mild to moderate heart failure
* edema (due to: heart failure, hepatic ,or renal disease
* diabetes insipidus (reduces the overproduction of urine by 30% to 50%)

Hydrochlorothiazide (HCTZ)

* Adverse effects

* moderate hyponatremia, hypochloremia, & dehydration
* hypokalemia
* hyperglycemia
* hyperuricemia (gout)

Hydrochlorothiazide (HCTZ)

* Drug Interactions

* digoxin (toxicity due to hypokalemia)
* NSAIDS can limit the effect
* other antihypertensive drugs

What do Potassium-Sparing Diuretics do?

they produce a modest increase in urine production

What are the 2 categories of Potassium-Sparing Diuretics?

* aldosterone antagonists
* Spironolactone (aldactone)
* non-aldosterone antagonists
* triamterene (dyrenium)

Spironolactone (aldactone)

* Mechanism of Action

blocking aldosterone causing

delayed effect (up to 48hrs)

* sodium excretion
* potassium retention

Spironolactone (aldactone)

* Therapeutic Uses

* HTN & Edema
* Most commonly used in combo with thiazide or loop diuretic
* heart failure
* reduces mortality & hospital visits
* protects heart & blood vessel

Spironolactone (aldactone)

* Adverse effects

* hyperkalemia
* Endocrine effects: menstrual irregularities, impotence, hirsutism, deepening of voice

Spironolactone (aldactone)

* Drug Interactions

due to risk of hyperkalemia use the following w/ caution

* ACE inhibitors
* ARBS
* direct renin blockers

potential to cause fetal harm

What precautions do you take when cutting/crushing Spironolactone?

* gown
* double up on chemo gloves

Triamterene (dyrenium)

direct inhibitor of the sodium-potassium pump causing:

* sodium excretion
* potassium retention

Acts quicker than Spironolactone

* works in hours not days

Triamterene (dyrenium)

* therapeutic effects

* Hypertension
* Edema

Triamterene (dyrenium)

* adverse effects

* hyperkalemia
* nausea
* vomiting
* leg cramps
* dizziness

What is the Osmotic Diuretic?

Mannitol (osmitrol)

* ONLY osmotic diuretic in the US

Osmotic Diuretic

* mannitol

* IV admin ONLY
* filtered by glomerulus
* has minimal reabsorption → inhibits passive reabsorption of water
* ex: shifts fluid into bloodstream = ↓ pressure in thee brain
* effects start 30-60 min & lasts 6-8 hrs

Mannitol (osmitrol)

* Therapeutic Uses

* prophylaxis of renal failure
* reduction of inter cranial pressure

Mannitol (osmitrol)

* Adverse effects

* edema
* use x-treme caution w/ CHF & Pulmonary Edema

What are the Intracellular Ions?

* Mg+
* K+
* Phosphate

What are the Extracellular Ions?

* Na
* Cl
* Ca
* HCO3-

Hypotonic Solution

Cell Swell

* more volume, less solute

Isotonic Solution

same concentration

* NO change

Hypertonic solution

Cell Shrink

* more solvent, less fluid

Potassium Replacements

* potassium salts
* KCL PO or IV
* K+ phosphate IV
* K+ bicarbonate IV

IV Potassium for Hypokalemia

Primary KCL

* used for severe hypokalemia of NPO PT’s
* NEVER IV PUSH
* infuse slowly (No fatser than 10mEQ/hr)
* causes vein irritation
* central line is the best
* give very dilute when going through the peripheral

PO Potassium Replacement

* KCL
* K-Dur
* Sustained release tabs
* Klor-con, Micro-K → powder that dissolves in liquid)

PO Potassium Replacement

* Adverse effects

* GI irritation
* take w/meals or full glasses of water

Regulation of Potassium Levels

* hyperkalemia treatment

Mild to Moderate

* kayexalate (PO or PR)

Severe

* dextrose & insulin IV
* if acidioic: sodium bicarb infusion
* calcium gluconate IV (for heart)
* dialysis

Magnesium replacement

* Mg Hydroxide
* tabs or liquid (MOM)
* Severe deficiency
* IV MG Sulfate
* AVOID w/ PT’s that have AV heart block

Magnesium replacement

* Adverse effects

* x-cessive amounts of neuromuscular blockade
* calcium gluconate = antidote