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Pharmacology > Magnesium & potassium > Flashcards

Magnesium & potassium Flashcards

1
Q

Extracellular concentrations are low

A

Potassium

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2
Q

Conducting nerve impulses

Maintaining the electrical excitability of muscle

Regulating acid-base balance

A

Potassium

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3
Q

Regulation of potassium is primarily regulated by the _____

A

kidneys

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4
Q

Renal excretion increased by aldosterone

Excretion also increased by most diuretics (specifically loop diuretics & thiazide diuretic = can lead to low levels )

A

potassium

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5
Q

Potassium-sparing diuretics are the exception (some are aldosterone antagonist which means they keep potassium, increase potassium)
Influenced by extracellular pH—- increase or decrease potassium

A

increase

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6
Q

Potassium uptake enhanced

A

Alkalosis

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7
Q

Potassium exits cells

A

Acidosis

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8
Q

_____ has a profound effect on potassium level : it helps pull potassium back into the cell

A

Insulin

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9
Q

weakness or paralysis of skeletal muscle
risk of fatal dysrhythmias,
intestinal dilation and ileus.

A

s/s of hypokalemia

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10
Q

Serum potassium levels less than 3.5 mEq/L

A

Hypokalemia

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11
Q

Most common cause is treatment with a thiazide or loop diuretic

Less common: Excessive insulin, alkalosis

Adverse effects on skeletal muscle, smooth muscle, blood pressure, and heart

A

Hypokalemia

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12
Q

Potassium salts preferred because chloride deficiency frequently coexists with hypokalemia

A

Hypokalemia treatment

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13
Q

Oral potassium chloride: Mild

A

Hypokalemia treatment

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14
Q

Sustained-release version has fewer GI effects

Especially for prevention

Abdominal discomfort, nausea and vomiting, diarrhea

A

Oral potassium chloride: Mild (Hypokalemia treatment)

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15
Q

Oral potassium chloride should be taken with meals or a full glass of water

A

True

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16
Q

Oral potassium chloride: Mild

Dosages for_____: 16 to 24 mEq/day

A

prevention:

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17
Q

Oral potassium chloride: Mild

Dosages for _____ 40 to 100 mEq/day

A

deficiency:

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18
Q

IV potassium chloride: Severe or cannot take PO

A

Hypokalemia treatment

19
Q

Must be diluted and infused slowly

Potassium must also be infused slowly (generally no faster than 10 mEq/hr in adults)

Potassium chloride must never be administered by IV push
Results in cardiac arrest

A

IV potassium chloride: Severe or cannot take PO

Hypokalemia treatment

20
Q

Must be diluted and infused slowly
IV solutions must be diluted (preferably to 40 mEq/L or less)
IV solutions are extremely irritating to the veins

A

IV potassium chloride: Severe or cannot take PO

Hypokalemia treatment

21
Q

Avoid in patients who are predisposed to hyperkalemia

Severe renal impairment, use of potassium-sparing diuretics, hypoaldosteronism

A

Contraindications to potassium use

22
Q

Principal complication of hypokalemia is hyperkalemia

Assess renal function and changes in ECG

A

True

23
Q

Excessive elevation of serum potassium

A

Hyperkalemia

24
Q

Severe tissue trauma

Untreated Addison’s disease

Acute acidosis (draws potassium out of cells)

Misuse of potassium-sparing diuretics

Overdose with IV potassium

A

Causes of hyperkalemia

25
Q

Disruption of electrical activity of the heart

A

Hyperkalemia

26
Q

____elevation (5 to 7 mEq/L): T wave heightens; PR prolonged

A

Mild (hyperkalemia)

27
Q

____ elevation (8 to 9 mEq/L): Cardiac arrest can occur

A

Severe

28
Q

Confusion, anxiety, dyspnea, weakness or heaviness of legs, numbness/tingling of hands/feet/lips

A

Noncardiac signs of hyperkalemia

29
Q

alterations in the ECG and cardiac rhythm (eg, peaked T wave, prolonged PR interval, ventricular tachycardia or fibrillation, cardiac arrest)

confusion

anxiety

dyspnea,

weakness or heaviness of the legs, and numbness or tingling of the hands, feet, and lips.

A

S/s of hyperkalemia

30
Q

Withhold foods that contain potassium

Withhold medicines that promote potassium accumulation: Potassium-sparing diuretics, potassium supplements

Counteract potassium-induced cardiotoxicity

A

Hyperkalemia treatment

31
Q

Lower extracellular levels of potassium

  Calcium salt (eg, calcium 
  gluconate)

Infusion of glucose and insulin

If acidosis is present: Infusion
of sodium bicarbonate

Oral or rectal administration of
sodium polystyrene sulfonate
[Kayexalate, Kionex]

Peritoneal or extracorporeal
dialysis

A

Hyperkalemia treatment

32
Q

Required for the activity of many enzymes

Binding of messenger RNA to ribosomes

Helps regulate neurochemical transmission and the excitability of muscle

A

Magnesium

33
Q

1.5 to 2.4 mEq/L.

A

Magnesium

34
Q

Diarrhea

Hemodialysis

Kidney disease

Prolonged IV feeding

Chronic alcoholism

A

Causes of hypomagnesemia

35
Q

Involve cardiac and skeletal muscle

Low magnesium prompts the release of acetylcholine at the neuromuscular junction, this will increase muscle excitability to the point of tetany

Increases the excitability of neurons in the CNS, can lead to disorientation, psychosis and seizures

A

Hypomagnesemia

36
Q 
muscle excitability
tetany 
disorientation
psychoses
seizures.
A

s/s of hypomegnesemia

37
Q

Prevention and treatment
Magnesium oxide
Magnesium sulfate
IM or IV

A

Prevention and treatment of hypomegnesmia

38
Q

Critically low levels of magnesium will need IV replacement

Magnesium Sulfate 10% solution, infused at a rate of 1.5 mL/min

Typically the infusion rate is one gram per 60 minutes in asymptomatic patients

There are exceptions to this (Torsades de Pointes)

A

treatment for hypomagnesemia

39
Q

Most common in patients with renal insufficiency

Especially when patient uses magnesium-containing antacids or cathartics

Symptoms of mild intoxication: Muscle weakness, hypotension, sedation, and ECG changes

A

Hypermagnesemia

40
Q

Respiratory paralysis: Plasma levels of 12 to 15 mEq/L

A

Hypermagnesemia

41
Q

Higher magnesium concentrations: Risk of cardiac arrest

A

Hypermagnesemia

42
Q

Muscle weakness and paralysis can be counteracted with IV _____

A

calcium (hypermagnesemia)

43
Q

The nurse should assess the patient for neuromuscular blockade, which can occur as a result of elevated levels of magnesium.

Paralysis of the respiratory muscles is a particular concern. An injectable form of calcium (calcium gluconate) should be immediately available for patients receiving magnesium sulfate.

The ECG should be monitored because excessive magnesium can suppress conduction through the AV node.

To minimize the risk of toxicity, serum magnesium levels should be monitored. Respiratory paralysis occurs at 12 to 15 mEq/L. When magnesium levels exceed 25 mEq/L, cardiac arrest may occur.

A

Nursing considerations

Pharmacology (2 decks)

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