This document provides a summary of pharmacology of the electrolyte, potassium, in the human body including:
- normal functions of potassium
- normal lab values for potassium
- causes of potassium imbalance
- signs and symptoms of potassium imbalance
- treatment of potassium imbalance
- p...
Potassium Disorders ⑳
Normal Level: 3.5-5 mEq/L If serum potassium levels are
Normal Function: Muscle Contraction in muscles, especially the Myocardium low, it’s because it is stuck
Potassium is normally intracellular while sodium is extracellular, maintaining the resting potential of muscle cells. When stimulated, inside the cells, so the muscles
potassium channels close and the cell depolarizes, allowing the muscle to contract. Once complete, potassium channels open to allow can’t relax, which can lead to
potassium to leave the cell to repolarize it, aka stop the action potential, and allow muscle relaxation.
muscular symptoms
Hypokalemia
Hypokalemia: < 3.5 mEq/L Mild Sx: Asymptomatic
·
Mod Sx: Weakness, cramps, muscle pain
Severe: ≤ 2.5 mEq/L or symptomatic Seve Sx: Arrhythmia, EKG changes
Causes: Intracellular shift
B-adrenergic agonists Goal: 4 mEq/L
Insulin
Medications
Diuretics
GI Loss or lack of supplementation
Treatment
• if hypomagnesemia is also present, correct the magnesium first.
• Every 10 mEq administered raises serum potassium by 0.1 mEq/L
If serum potassium levels are high, it’s
Acute Treatment because it is stuck outside the cells, so the
• Oral preferred if mild and able to
muscles are too relaxed and can’t
20-40 mEq per dose to minimize GI side effects
• IV preferred if severe (refer to above) contact, which can lead to muscular
10 mEq/hr max, unless in ICU via central line then 20 mEq/hr max symptoms. If the heart can’t contract, it
can’t beat, which is why calcium is
Chronic Treatment administers to stimulate muscular
• potassium sparing diuretics
Amiloride, Spironolactone, Triamterene contraction.
Hyperkalemia
Hyperkalemia: > 5 mEq/L Sx:
·
muscle twitching
muscle cramps
Severe: ≥ 6.5 mEq/L or symptomatic weakness
ECG changes
Causes: Extracellular shift
arrhythmia
Beta blockers
Succinylcholine
Alteration to RAAS system Goal: <5 mEq/L
ACE inhibitors/ARBS
aldosterone antagonists
NSAIDs
Medications
K-sparing diuretics
AKI or Kidney Disease
Treatment
• if ECG changes are present, administer Calcium gluconate or Calcium Chloride first to stabilize the heart
Insulin + Dextrose FIRST LINE symptomatic AND no ECG CHANGES Rapidly promote K to move
Intracellular shift Albuterol FIRST LINE severe (refer to above) into cells, lowering
Sodium Bicarbonate extracellular plasma levels
LAST LINE for hyperkalemia refractory to treatment
Hemodialysis
Furosemide SECOND LINE symptomatic Ascending loop of Henley:
Increased FIRST LINE mild Asymptomatic promotes Na and water loss,
(Lasix)
excretion Not for severe or symptomatic hyperkalemia along with potassium
Sodium Polyesterene SECOND LINE symptomatic Intestine: 1 g exchanges 1
Sulfate FIRST LINE mild Asymptomatic mEq of Na for 1 mEq of K.
(Kaexylate) Not for severe or symptomatic hyperkalemia Potassium is excreted in feces
Sodium Zirconium SECOND LINE symptomatic Intestine: exchanges Na for K. Edema
(Lokelma) FIRST LINE mild Asymptomatic K is excreted in feces. 10 g
Not for severe or symptomatic hyperkalemia drops serum k by 1 mEq
Patiromer SECOND LINE symptomatic Intestine: Binds to K and Low
(Valtassa) FIRST LINE mild Asymptomatic passes through GI for magnesium
Not for severe or symptomatic hyperkalemia excretion in feces
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