Pharmacology, part 27: Nervous System Medications for Anxiety and Depression


In this article, we cover a few common medications used to treat both depression and anxiety. 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.

Cool Chicken 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!

Selective serotonin reuptake inhibitors (SSRIs) - paroxetine, sertraline, fluoxetine.

Selective serotonin reuptake inhibitors (SSRIs) like paroxetine (Paxil), sertraline (Zoloft) and fluoxetine (Prozac) are types of antidepressants used to treat anxiety, depression, obsessive compulsive disorder (OCD) and post-traumatic stress disorder (PTSD).

Mode of action

SSRIs work by increasing levels of serotonin in the brain. Serotonin is a neurotransmitter that carries signals between brain nerve cells (neurons). SSRIs block the reabsorption (reuptake) of serotonin into neurons, therefore increasing the amount of serotonin available to improve transmission of messages between neurons.

Side effects

Side effects of SSRIs include sexual dysfunction, weight gain and insomnia.

Black box warning

SSRIs carry a block box warning due to the increased risk of suicidal thoughts in some patients.

Cool Chicken If you are the parent of a teen, you may need an SSRI (i.e. paroxetine, fluoxetine) to cope with depression/anxiety.

Serotonin syndrome

Serotonin syndrome is a potentially life-threatening condition that happens when there is too much serotonin in the body. Symptoms of serotonin syndrome can include agitation, hallucinations, fever, diaphoresis (sweating), and tremors. These symptoms usually occur within several hours of taking a new drug or increasing the dose of a drug.


These medications should NOT be taken concurrently with St. John’s wort due to the increased risk for patients getting serotonin syndrome.

St. John's wort is a plant with yellow flowers that has been used in traditional medicine as far back as ancient Greece. The flowers are used to make liquid extracts, pills, and teas. Today it is mainly used as an over-the-counter remedy to treat mild and moderate depression, seasonal affective disorder (SAD), mild anxiety, and sleep problems.

Nursing care

When caring for a patient on SSRIs, it’s important to inform them that it will take several weeks before they start feeling the effects of these medications. They should not discontinue use early

Serotonin-norepinephrine reuptake inhibitors (SNRIs) - duloxetine, venlafaxine

Serotonin-norepinephrine reuptake inhibitors (SNRIs) like duloxetine (Cymbalta) and venlafaxine (Effexor) are a class of medication used to treat depression, anxiety disorders and neuropathic pain. Because they affect two important neurotransmitters, serotonin and norepinephrine, they are sometimes called dual reuptake inhibitors or dual-acting antidepressants.

Mode of action

SNRIs work by inhibiting the reabsorption (reuptake) of both serotonin and norepinephrine in the body. This increases the availability and amount of these neurotransmitters and helps treat depression, anxiety and neuropathic pain.

Side effects

Side effects with SNRIs can include fatigue, insomnia, GI upset, constipation, nausea, dysuria (painful or difficult urination), and decreased libido.

Black box warning

Just like SSRIs, SNRIs carry a black box warning because it can increase the risk of suicidal thoughts in patients.

Serotonin syndrome

Serotonin syndrome can also occur while taking SNRIs because this medication increases levels of serotonin in the body. Symptoms can include agitation, hallucinations, fever, diaphoresis (sweating), and tremors.

Cool Chicken I don’t need a deluxe apartment to be happy, I just need to take duloxetine for my depression.

Full Transcript: Pharmacology, part 27: Nervous System Medications for Anxiety and Depression

In this video, we are going to talk about some medications that are used for both depression and anxiety. If you are following along with cards, I'm on card 59 in our Pharmacology Edition 2.0 flashcards.

Let's first talk about selective serotonin reuptake inhibitors or SSRIs. This class of medication includes drugs such as paroxetine, sertraline, and fluoxetine. You can see that they all end in that tine type of ending.

So these medications can be used, like I said, for anxiety. They can also be used for depression as well as OCD and PTSD.

They work by inhibiting serotonin reuptake, which increases the amount of serotonin in your system.

So side effects of this include sexual dysfunction, which is very common with SSRIs as well as weight gain and insomnia.

There's also a black box warning with this medication because it could increase suicidal thoughts in some patients.

So the way I remember that fluoxetine, paroxetine, sertraline all are used for depression or anxiety is that if you live with a teen, like I do, then there may be times where you feel like you need a medication for anxiety or depression because teens are a piece of work sometimes, especially during a pandemic. Anyway, so that's my little tip.

When your patient is on an SSRI, you need to carefully monitor your patient for serotonin syndrome, and this is a very important point. So symptoms of serotonin syndrome include agitation, hallucinations, fever, diaphoresis, which is sweating, as well as tremors. So everything's kind of amped up. You're sweating, hallucinating, have a fever. If your patient has those symptoms and they're on an SSRI, then you definitely need to suspect serotonin syndrome.

Also keep in mind is that you don't want to take this concurrently with St. John's wort because that can increase the patient's risk for getting serotonin syndrome.

And then also keep in mind that when a patient first starts on an SSRI, it takes several weeks before they really start feeling the effects of this medication.

Alright, now let's talk about SNRIs. These are serotonin-norepinephrine reuptake inhibitors.

So unlike what we had with SSRIs where we were inhibiting the reuptake of just serotonin, with these medications, we are inhibiting the reuptake of both serotonin and norepinephrine, which increases the amount of serotonin and norepinephrine we have in the body.

Medications that fall within this class include duloxetine and venlafaxine.

So side effects with SNRIs include fatigue, insomnia, GI upset including constipation and possible nausea, dysuria, and decreased libido.

We also have a black box on this medication because it can increase the risk of suicidal thoughts in patients who take SNRIs.

So when the patient is on an SNRI, of course, you're going to want to monitor for serotonin syndrome because with this medication we're also increasing levels of serotonin.

So again, those important symptoms to remember are agitation, hallucinations, fever, diaphoresis, and tremors.

So my little trick for remembering at least one of these medications is, "I don't need a deluxe apartment to be happy, I just need to take duloxetine for my depression." So hopefully that will help you remember that duloxetine is for depression and it is an SNRI.

So that is it for this video. When we come back, we will talk about medications that are used for bipolar disorder. Hang in there with me!

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Thumbs up Cathy this is very informative.

Sukoluhle Nkomo

Paroxetine and Fluoxetine attended Sertraline university to study Anxiety and Depression


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