Pharmacology, part 16: Cardiovascular Medications - Electrolyte & Acid/Base Imbalances

by Cathy Parkes

In this video

Calcium — calcium carbonate (Caltrate, Mylanta, Rolaids, Tums), calcium citrate (Citracal), calcium gluconate (Kalcinate)

  • Indications
  • Mode of action
  • Side effects
  • Expected range of calcium

Potassium chloride

  • Indications
  • Administration
  • Side effects
  • Normal range for potassium

Sodium bicarbonate

  • Indications
  • Mode of action
  • Side effects
  • Bicarbonate level

Sodium polystyrene sulfonate (Kayexalate)

  • Indications
  • Mode of action
  • Side effects
  • Nursing care

Magnesium supplements (magnesium chloride, magnesium oxide, magnesium gluconate)

  • Indications
  • Key side effect
  • Complications - magnesium toxicity
    • Symptoms
    • Easy way to remember
    • Antidote
  • Nursing care
  • Normal range of magnesium

Full transcript

Okay. In this video, we are going to talk about some medications that are used to correct electrolyte imbalances and acid-base imbalances in the body.

Let's first talk about calcium. So we have calcium carbonate, calcium citrate, and calcium gluconate.

So calcium carbonate and calcium citrate are used for hypocalcemia, and they are also used to help prevent post-menopausal osteoporosis.

Calcium gluconate can be used for emergency treatment of hyperkalemia and hypermagnesemia. So if our patient's potassium or magnesium levels are way too high, then calcium gluconate is going to be the antidote.

The mode of action -- calcium is an important mineral needed for bone and teeth formation as well as nerve and muscle function and clotting.

In terms of side effects, if we have too much calcium, that can cause constipation as well as dysrhythmias such as bradycardia.

So keep in mind the expected range of calcium in the bloodstream, which is between 9 and 10.5.

Also keep in mind that in order for your patient to absorb calcium, they need sufficient vitamin D as well.

Now let's talk potassium chloride, which is a potassium supplement used to treat high hypokalemia.

So potassium is a really important electrolyte needed to maintain intracellular fluid volume. It's also super important for nerve, muscle, and heart function.

We can give a potassium supplement through the oral route or the IV route. When you're giving it through the oral route, it comes in these huge horse pills. It's literally this big, which sometimes is an issue for patients to swallow.

You can also get it in this powder, which kind of turns the water orange, and per my patients, tastes really disgusting.

Or you can give it through the IV route, which can cause some burning at the IV site. So you can request that your doctor write an order that it be mixed with lidocaine so that doesn't burn so much when you're giving it through the IV route.

So in terms of side effects, arrhythmias is going to be the really important one to remember here. So with potassium levels, if your potassium levels are too high or too low, the thing you need to worry about for your patient is dysrhythmias. So we need to make sure their potassium levels stay in the right zone because whether they go up too high or too low, then we could have fatal heart arrhythmias.

The normal range for potassium is between 3.5 and 5.

Let's talk about sodium bicarbonate, which is an alkalinizing agent that can be used for metabolic acidosis as well as peptic ulcer disease.

I also have seen it used many times in a code blue situation when a patient has cardiac arrest and resulting acidosis.

So it works by promoting an acid-base balance in the body by releasing bicarbonate ions.

In terms of side effects, if we give too much of this, then we can end up with metabolic alkalosis.

So during therapy, we're definitely going to want to monitor the patient's ABGs and make sure their bicarbonate level is somewhere between 22 and 26.

Now let's talk about sodium polystyrene sulfonate, which is Kayexalate. And that is exactly how I'm going to refer to it for the rest of this little segment of video just because the sodium polystyrene sulfonate is a mouthful, and I can't tell you how many times I've cut this video.

So Kayexalate is a hypokalemic agent, so it's used to help bring down potassium levels when we have hyperkalemia.

It works by exchanging sodium ions for potassium ions in the intestine, which helps to increase excretion of potassium from the body.

So side effects can include constipation, fecal impaction, nausea and vomiting, and possible hypokalemia. Right? If we bring down those potassium levels too far, we can end up with a different problem, with hypokalemia. And remember, anytime we have hyperkalemia or hypokalemia, the patient is at risk for arrhythmias.

So the expected range for potassium is between 3.5 and 5.

And you definitely want to monitor your patients' stools during therapy for constipation and possible fecal impaction. And it may be necessary to give them a laxative concurrently with Kayexalate during therapy.

Finally, let's talk about magnesium supplements, which can include magnesium chloride, magnesium oxide, and magnesium gluconate.

So we would use these supplements to treat hypomagnesemia. We can also use magnesium to treat a dysrhythmia called torsades de pointes, which I talk more about in my EKG video series.

Magnesium can also be used to treat pre-term labor because it helps to slow uterine contractions.

So magnesium is an important electrolyte needed for nerve and muscle function as well as bone formation. It is also critical for many biochemical reactions in the body.

So the key side effect with magnesium supplements is going to be diarrhea. Very common.

But in addition, we need to be on the lookout for magnesium toxicity, and knowing the signs and symptoms of magnesium toxicity is going to be really important for you to know for the NCLEX and for your nursing exams.

So these symptoms include decreased deep tendon reflexes, a urine output that falls below 30 ml an hour. Also respiratory depression is a sign of magnesium toxicity, as well as cardiac depression, including hypotension.

So the way I remember these side effects is I remember that, "Too much magnesium brings Maggie to her knees," due to that respiratory depression and cardiac depression.

So keep in mind for magnesium toxicity, we can give calcium gluconate, which we talked about a little bit earlier, and then we're also going to want to keep an eye on your patient's magnesium levels. So those should be between 1.3 and 2.1.

And that, my friends, is the end of the cardiovascular section of our Pharmacology flashcards, edition 2.0. If you have found these videos helpful, be sure to like and comment on our videos, and share link with your classmates and friends in nursing school. So next up, we're going to be covering important medications that you need to know for the nervous system. Thanks so much for watching!

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