Pharmacology, part 20: Nervous System Medications for Bipolar
February 23, 2021 Updated: December 29, 2021 8 min read
In this article, we cover some medications used to treat bipolar disorder. The Nursing Pharmacology video series follows along with our Pharmacology Flashcards, which are intended to help RN and PN nursing students study for nursing school exams, including the ATI, HESI, and NCLEX.
When you see this Cool Chicken, that indicates one of Cathy's silly mnemonics to help you remember. The Cool Chicken hints in these articles are just a taste of what's available across our Level Up RN Flashcards for nursing students!
Lithium is a mood-stabilizing medication used to treat bipolar disorder. It works to decrease the intensity of manic symptoms and decrease the severity of depressive symptoms to help a patient achieve a more stabilized mood.
Mode of action
Lithium works by influencing the reuptake of neurotransmitters.
Lithium has many side effects which may make it difficult for patients to stay on this medication when it is prescribed to them for bipolar disorder.
Lithium can cause fine hand tremors. When a patient is taking lithium, fine hand tremors are expected. If those hand tremors become coarse hand tremors, that is indicative of toxicity. When it comes to hand tremors, fine and coarse are measures of amplitude. Fine tremors have a tiny range of motion and are barely noticeable. Coarse hand tremors have a larger range of motion (larger displacement) and are very noticeable.
Lithium has major effects on the kidneys, including possible kidney toxicity, as well as nephrogenic diabetes insipidus. We covered diabetes insipidus in our Med-Surg Flashcards, and this is the same disorder, but because of lithium's effect on the kidneys, the disorder is nephrogenic, meaning that it originates in the kidneys as opposed to the brain. Lithium-induced nephrogenic diabetes insipidus causes polyuria, which is the excretion of large volumes of dilute urine.
Lithium side effects = LITH! Leukocytosis, Insipidus, Tremors, Hypothyroidism.
Black box warning
Lithium carries a black box warning due to the risk of lithium toxicity that can occur from excessive lithium intake.
When a patient is on lithium, ensure that you closely monitor their plasma levels to avoid lithium toxicity
Expected plasma levels
The expected therapeutic range of lithium is 0.6-1.2 mEq/L. Amounts over 1.5 mEq/L are indicative of lithium toxicity. This is one of the few KEY medication therapeutic ranges that is included in our Lab Values Flashcards for Nursing Students, because it's so important to know!
Signs of toxicity
Signs of lithium toxicity include coarse tremors, confusion, hypotension, seizures and tinnitus.
If you have a patient on lithium, there are some important teaching tips to be aware of.
When a patient is on lithium, they need to maintain an adequate intake of sodium and fluids to counteract kidney damage. Lithium and sodium have an inverse relationship. As sodium levels fall, lithium levels rise. It is important for patients to maintain an adequate intake of sodium to avoid lithium toxicity. Additionally, patients should be taught to avoid activities that would decrease their sodium levels, such as strenuous exercise or spending time in hot environments.
A patient on lithium should also avoid certain medications to prevent toxicity. Lithium is contraindicated with diuretics. Diuretics remove sodium and water from the body, which is the opposite of what a patient on lithium needs. Patients on lithium should also avoid anticholinergics and NSAIDs. These medications are also covered in our Pharmacology flashcards (Cardiovascular section).
NSAIDS can cause kidney toxicity, and lithium already carries a risk of kidney toxicity, so it's important for a patient to avoid anything that could pose an additional risk to the kidneys.
Likewise, if a patient has renal disease, they should not take lithium because their kidneys have already been damaged.
Lithium and its side effects should definitely be included in your pharmacology and NCLEX exam prep!
Anticonvulsants for bipolar - carbamazepine, valproic acid, lamotrigine
There are some anticonvulsant medications you should be familiar with for your exams. Three anticonvulsant medications used for bipolar are carbamazepine, valproic acid, and lamotrigine. These medications can be used for seizures and epilepsy as well as bipolar disorder.
All three of these medications carry serious side effects and black box warnings that you should be aware of.
Carbamazepine (Carbatrol, Tegretol)
Carbamazepine is an anticonvulsant medication that works to decrease synaptic transmission in the central nervous system, which can reduce seizures and stabilize moods in someone with bipolar disorder.
We covered these disorders in depth in our Med-Surg Series (immune system).
Carbamazepine has often caused vision problems, serious skin rashes, and hypo-osmolarity.
Osmolarity is the concentration of a solution, in this case blood. If blood is hypo-osmolar, it is not concentrated enough, meaning it is diluted with too much water. Carbamazepine can cause syndrome of inappropriate ADH (SIADH), which causes retention of water, diluting the bloodstream and resulting in hypo-osmolarity.
Black box warning
Carbamazepine carries a black box warning due to the risk of anemia, serious skin rashes, and leukopenia.
When a patient is taking carbamazepine, you will need to monitor their CBC levels because of the risk of blood dyscrasias. Patients on carbamazepine should also be monitored for signs of infection because their white blood cell count is impacted, which places them at higher risk for infection.
Valproic acid (Depakene)
Valproic acid is an anticonvulsant medication that works to increase GABA (an inhibitory transmitter) in the central nervous system to prevent seizures and reduce the severity of bipolar symptoms.
Valproic acid can result in some serious side effects, including hepatotoxicity, pancreatitis, GI upset, and thrombocytopenia.
Black box warning
Valproic acid carries a black box warning for its risk of hepatotoxicity and pancreatitis, as well as potential neural tube defects in developing fetuses.
When a patient is taking valproic acid, you will need to monitor their liver function, including AST, ALT, and bilirubin levels. These labs are important to monitor due to the risk of valproic acid causing hepatotoxicity.
Bilirubin is a yellow substance found in vile, produced during the normal breakdown of red blood cells. The expected range of bilirubin is .3 -1 mg/dL.
Elevated levels of bilirubin can be caused by liver dysfunction, bile duct obstruction, hemolytic or pernicious anemia, or a transfusion reaction.
Bilirubin is just one of the KEY important lab values you need to know for your nursing exams and nursing practice, and it's covered in our Nursing Lab Values flashcards.
Lamotrigine is an anticonvulsant that works by inhibiting sodium transport, meaning that it is a sodium channel blocker.
Lamotrigine can result in some side effects including dizziness, GI upset, photosensitivity, and rash.
Black box warning
Lamotrigine carries a black box warning due to the risk of serious skin conditions such as Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis. These are life-threatening dermatological conditions! Any rash should be promptly reported to the provider in a patient taking lamotrigine.
In this video, we are going to talk about medications that are used to treat bipolar disorder. And we're going to start by talking about lithium which is a mood stabilizer.
If you are following along with cards, I'm on card 61. And you'll notice on the back of card 61, there is a lot of bold, red items because there are a lot of things that are important to know about lithium. So like I said, lithium treats bipolar disorder.
It works by influencing the reuptake of neurotransmitters. It has many side effects which makes it difficult for patients to stay on this medication when they need it for bipolar disorder.
So side effects can include GI upset, fine hand tremors, polyuria due to nephrogenic diabetes insipidus that lithium causes. Also weight gain is very common with lithium. Kidney toxicity is a big risk with lithium and we'll talk a little bit more about that. Electrolyte imbalances, fatigue, hypothyroidism, as well as leukocytosis, are other side effects to be familiar with.
So one way to remember at least some of these side effects is to think of the word LITH.
So in the word lith, L stands for leukocytosis.
I stands for insipidus which we'll hope hopefully remind you that lithium can cause diabetes insipidus and polyuria.
T stands for tremors. So when a patient's on lithium, fine hand tremors are expected. If those hand tremors turn into coarse hand tremors, that is indicative of toxicity.
And then, the H stands for hypothyroidism.
So lithium carries a black box warning because of the risk of lithium toxicity. So when your patient is on lithium, you're going to want to closely monitor their plasma levels.
Plasma levels should stay under 1.5. If they get above 1.5, this can cause toxicity.
Signs of toxicity include coarse tremors, confusion, hypotension, seizures, and tinnitus.
If your patient's on lithium, you need to provide some very important teaching.
While the patient's on lithium, they need to maintain an adequate intake of both sodium and fluids. And this is very important to know.
Also, your patient needs to avoid certain medications in order to prevent toxicity. One thing they should avoid is diuretics. Why? Well, diuretics get rid of sodium and water. And that is the opposite of what we want to do with lithium. So no diuretics. No anticholinergics and no NSAIDS.
So NSAIDS are hard on the kidneys. And since this medication already carries a risk for kidney toxicity, we don't need to do any more damage to the kidneys.
So those are going to be some important medications that your patient should avoid.
In addition, if you have a patient who has renal disease, they would not take lithium. It would be contraindicated.
So hopefully, this information's been helpful. Like I said, all of the things we've talked about are on the back of this card. And they're important to know so definitely review those because you will likely need to know those for the NCLEX and in all likelihood, your nursing exams as well.
Now let's talk about some anticonvulsants which are also used to help treat bipolar disorder. So three medications that fall within this class that I'd be familiar with include carbamazepine, valproic acid, and lamotrigine.
These medications can be used for seizures and epilepsy as well as for bipolar disorder.
All three of these meds have some serious side effects. And they all have a black box warning. So let's go through some of those key side effects.
So for carbamazepine, a key possible side effect are blood dyscrasias. So these blood dyscrasias can include anemia, thrombocytopenia, as well as leukopenia.
In addition, carbamazepine has often caused issues with vision for patients.
And it can also result in hypo-osmolarity in patients. This is because with this drug, it can cause SIADH or syndrome of inappropriate ADH. And this SIADH causes the retention of all this water which dilutes the bloodstream and can result in this hypo-osmolarity.
And then serious skin rashes are also a risk with carbamazepine.
So like I said, this drug, as well as the other two we'll talk about, does carry a black box warning. The black box warning for carbamazepine is due to the anemia, the potential for serious skin rashes, as well as that leukopenia.
So when your patient is on carbamazepine, you're definitely going to want to monitor their CBC levels because of the blood dyscrasias.
And then you're also going to want to monitor the patient for signs of infection because their white blood cell count is impacted, which places them at higher risk for infection. So that's going to be another thing to watch out for.
Valproic acid also has some serious side effects. So these side effects can include hepatotoxicity, pancreatitis, GI upset, as well as thrombocytopenia.
So valproic acid also carries a black box warning, specifically for that hepatotoxicity, pancreatitis. And then it also carries a risk for causing neural tube defects in developing fetuses.
So if your patient is going to be on valproic acid, you're definitely going to want to monitor their liver function. So you're going to be taking a look at their AST, ALT, and bilirubin levels because of that serious risk for hepatotoxicity.
And then, lastly with lamotrigine. Lamotrigine does carry some risks as well, including dizziness, GI upset, photosensitivity, and rash.
And the black box warning for lamotrigine is because of the risk for development of serious skin rashes.
Okay. In my next video, we will talk about medications that are used to treat psychotic disorders, including schizophrenia. If you have found value in this video, be sure to like it and to subscribe to us here at Level Up RN!
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