Antidepressants - SSRIs and SNRIs: Nursing pharmacology

Antidepressants are medications primarily used to treat major depressive disorder, which is a condition associated with a persistent feeling of sadness and loss of interest in everyday activities.

Even though the exact cause of major depressive disorder is still unknown, there's some evidence that suggests that it’s related to low levels of neurotransmitters called monoamines, which include serotonin, norepinephrine, and dopamine.

In this video, we’re going to cover two of the main classes of antidepressants: selective serotonin reuptake inhibitors and serotonin-norepinephrine reuptake inhibitors.First, let’s focus on selective serotonin reuptake inhibitors, or SSRIs for short, such as fluoxetine, fluvoxamine, sertraline, paroxetine, citalopram, and escitalopram.

SSRIs are taken orally, and once absorbed into the bloodstream, they travel to the brain. Here, SSRIs inhibit the reuptake of serotonin.

As a result, free levels of serotonin within the synaptic cleft are increased right away, although the effect of SSRIs alleviating symptoms of depression are not evident for a few weeks.

Other indications for SSRIs include anxiety disorders like obsessive-compulsive disorder, or OCD; post traumatic stress disorder, or PTSD; panic disorder and phobias; as well as eating disorders like bulimia.On the other hand, serotonin-norepinephrine reuptake inhibitors, or SNRIs, include duloxetine, venlafaxine, desvenlafaxine, and levomilnacipran.

SNRIs are also taken orally, and once they reach the brain, they inhibit the reuptake of both serotonin and norepinephrine, increasing their levels in the synaptic cleft.

Other indications for SNRIs besides major depressive disorder include generalized anxiety disorder and neuropathic pain.Now, the brain has different types of serotonin receptors besides the ones involved in depression.

Some of them mediate functions like mood, sleep, appetite, or sexual function. So, some side effects of SSRIs and SNRIs include anxiety or nervousness, agitation, insomnia or drowsiness, loss of appetite, and sexual dysfunction.

Other side effects include headache, dizziness, sweating, and hyponatremia, as well as bruxism, dry mouth, nausea, vomiting, and diarrhea.

Additionally, SSRIs and SNRIs can also cause serotonin syndrome, which usually occurs when these medications are combined with other antidepressants that increase the level of serotonin in the brain, especially monoamine oxidase inhibitors, or MAOIs for short.

Clients that develop serotonin syndrome typically present with skin flushing, hyperthermia, agitation, muscle rigidity, seizures, and altered mental status or even coma.Now, SNRIs also increase the levels of norepinephrine, so they can cause side effects like hypertension and tachycardia, as well as closed-angle glaucoma, and urinary retention.

Finally, an important boxed warning for all antidepressants is that they may increase the risk of suicidal thinking in children, adolescents, and young adults.SSRIs and SNRIs are contraindicated in clients taking MAOIs.

In addition, these medications should be used with caution during pregnancy, as well as in clients with renal or hepatic disease, diabetes, or glaucoma.

Finally, SSRIs and SNRIs should be used with caution in clients with risk factors for QT prolongation, as well as those who have had a myocardial infarction, or who are severely depressed or present with suicidal thinking.Now, before administering an SSRI or SNRI, obtain a baseline assessment of your client’s depressive symptoms and complete a suicide risk assessment.

Observe their behaviors and affect, and ask them about recent changes in appetite, sleep patterns, and activities. Next, assess your client’s baseline vital signs, weight, kidney and liver function tests, as well as serum electrolytes and pregnancy status.

Stress the importance of using an effective birth control method when taking these medications, and instruct your client to inform their healthcare provider if they think they might be pregnant.

Then, ensure your client understands why they are prescribed the medication. Stress the importance of taking their medication as directed, and remind them that they should not stop taking their medication abruptly, even when they start feeling better.

Also let them know that it may take a few weeks before they start feeling the therapeutic effects of their medication. Next, talk to your client about how to manage side effects they may experience during therapy.

Both SSRIs and SNRIs can cause sexual dysfunction, so let your client know that this is a common side effect and encourage them to talk to their health care provider if they experience this side effect.

Advise your client to take their medication in the morning to reduce the risk of insomnia, and remind them that if they feel tired or dizzy, they should avoid driving or engaging in other hazardous activities.

Finally, remind your client to report symptoms like headache or jaw pain, which could be a result of teeth clenching and grinding that can occur with these medications.Now, clients taking SNRIs may also experience urinary retention, so instruct your client to empty their bladder before taking their medication.

Also advise them to let their healthcare provider know if they are feeling palpitations or a faster heart rate.Okay, during the first few weeks of treatment, monitor your client closely for suicidal thoughts and make arrangements for them to meet with their healthcare provider regularly.

During treatment, continue monitoring for side effects and evaluate the effectiveness of treatment.Alright, as a quick recap ….

Two commonly used medications to treat major depressive disorder include SSRIs and SNRIs. SSRIs work by inhibiting the reuptake of serotonin, and SNRIs work by inhibiting the reuptake of serotonin and norepinephrine.

Nursing considerations include client education and monitoring for the effectiveness of treatment, and for side effects especially suicidal thinking, most commonly in children,