POTASSIUM

Potassium• Most abundant positively charged

electrolyte inside cells• 95% of body’s potassium is intracellular• Potassium content outside of cells ranges

from 3.5 to 5 mEq/L• Potassium levels are critical to normal

body function• Excess dietary potassium is excreted by

the kidneys in the urine.

Hyperkalemia

-excessive serum potassium level exceeding 5.5 mEq/L.

Causes:• Angiotensin-converting enzyme (ACE) inhibitors• Burns• Excessive loss from cells• Infections• Metabolic acidosis• Potassium supplements• Potassium-sparing diuretics• Trauma

Hypokalemia

-deficiency of potassiumserum level <3.5 mEq/L.

Causes:• Alkalosis• An increased secretion of mineralocorticoids• Burns• Corticosteroids• Crash diets• Diarrhea• Hyperaldosteronism

• Ketoacidosis• Loop diuretics• Malabsorption• Prolonged laxative misuse• Thiazide diuretics• Thiazide-like diuretics• Vomiting

Mechanism of Action

Potassium is responsible for:• Muscle contraction• Transmission of nerve impulses• Regulation of heartbeats• Acid-base balance

• Isotonicity• Electrodynamic

characteristics of the cell• Essential component of

gastric secretion• Renal function• Tissue synthesis• Carbohydrate synthesis

Indication-Used to treat thallium

poisoning and to help increase muscular strength in some patients with myasthenia gravis.

myasthenia gravis

Contraindication

• Known allergy to a specific drug product

• Hyperkalemia• Renal disease• Acute dehydration• Untreated Addison’s disease• Severe hemolytic disease• Extensive tissue breakdown

Adverse effectOral potassium therapy

-diarrhea, nausea, vomiting-GI bleeding and ulcerations

Parenteral administration-pain at the injection site-phlebitis

Interactionpotassium–sparing diuretics + ACE

inhibitors = hyperkalemia

diuretics + amphotericin B + mineralosteroids = hypokalemia

Drug profilesodium polystyrene sulfonate

(potassium exchange resin)-used to treat hyperkalemia-administered orally-no contraindications, but can

cause disturbances in electrolytes.

SODIUM

SODIUM• Most abundant positively

charged electrolyte outside cells.

• Normal concentration outside cells is 135 to 145 mEq/L.

Hyponatremia

- sodium deficiency and occurs when serum levels decrease below 135 mEq/L.

Manifestations:• Lethargy• Hypotension• Stomach cramps• Vomiting• Diarrhea• Seizures

Causes• Excessive perspiration• Prolonged diarrhea or

vomiting• Renal disorders• Adrenocortical impairment

Hypernatremia- sodium excess and occurs

when serum levels exceed 145 mEq/L.

Symptoms:• Edema• Hypertension• Red, flushed skin• Sticky mucous membranes• Increased thirst• Temperature elevation• Decreased or absent urination

Cause• Poor renal excretions• Inadequate water consumption• Dehydration

Mechanism of Action and Drug Effect• Major cation in the extracellular

fluid (ECF)• Control water distribution• Fluid and electrolyte balance• Osmotic pressure • Regulation of acid-base balance

IndicationsMild hyponatremia

-oral administration of sodium chloride tablets and / or fluid restriction

Pronounced sodium depletion-NS or lactated Ringer’s solution

administered intravenously

Contraindication•Know drug allergy•Hypernatremia

Adverse effectOral administration

-nausea, vomiting, and cramps

Parenteral administration-venous phlebitis

Interactions-not known to

interact significantly with any drugs

Drug profilesodium chloride

-used as a replacement electrolyte for either the prevention or treatment of sodium loss.

-diluent for the infusion of compatible drugs

-assessment of kidney function after a fluid challenge

*CONTRAINDICATION: hypertensive patients

Nursing Implications

• Parenteral infusions of potassium must be monitored closely– Rate should not exceed 20 mEq/hour– NEVER give as an IV bolus or undiluted

• Oral forms of potassium– Must be diluted in water or fruit juice to minimize GI distress

or irritation– Monitor for complaints of nausea, vomiting, GI pain, or GI

bleeding

• Monitor for therapeutic response–Normal lab values• RBCs, WBC, electrolyte levels

– Improved fluid volume status– Increased tolerance to activities

• Monitor for adverse effects