What Are SNRIs?
Serotonin Norepinephrine Reuptake Inhibitors and How They Work

Mental health conditions such as depression and anxiety can make you feel like you’re trapped in a dark room, with no clear way out. You may not know the best way to seek help, or even if the options available are the right ones for you. 

If this sounds familiar, you may encounter the option of antidepressants for managing your symptoms – which may lead to the question “What is an SNRI?”

Serotonin norepinephrine reuptake inhibitors, AKA SNRIs, are a medication which are commonly used to help people restore a sense of emotional and physical balance. But are they the right choice of medication for you?

Mission Connection can help you find the most suitable treatment fit for your needs and symptoms. This page can also help shed light on SNRIs for mental health treatment by discussing:

  • What SNRIs are
  • How SNRIs work
  • The conditions SNRIs are commonly used to treat
  • Commonly prescribed SNRI medications list
  • The differences and similarities between SNRIs vs SSRIs
  • SNRI side effects and risks
  • How to taper off SNRI medications safely
  • Answers to frequently asked questions about SNRIs
  • Where to find professional support for mental health treatment with medications
Serotonin Norepinephrine Reuptake Inhibitors and How They Work

What Are SNRIs?

SNRIs, or serotonin norepinephrine reuptake inhibitors, are a class of antidepressants that are primarily used to treat depression. However, they can also be used to treat a variety of other mental health conditions, including anxiety disorders, post-traumatic stress disorder (PTSD), and chronic pain. 

SNRIs, along with selective serotonin reuptake inhibitors (SSRIs), are referred to as “second-generation” antidepressants. They were first introduced to the American market in 1993, with the launch of venlafaxine for depression. Since the 90s, a variety of other SNRIs have been approved by the Food and Drug Administration (FDA) for the treatment of mental health conditions.1 

Similar to older antidepressants, such as tricyclics, SNRIs target the reuptake of certain brain chemicals involved in functions such as mood, sleep, and alertness. However, in contrast to these older antidepressants, SNRIs pose less of a risk of side effects as they tend to be better tolerated by many people.1 

For this reason, after SSRIs, SNRIs are often the first line of medical treatment for mental health conditions.  

How Do SNRIs Work?

Mental health conditions are complex; they’re believed to be the result of an interplay between genetics, biology, and experiences. However, one long-running theory behind why some people develop mental health issues is that they have a chemical imbalance in the brain. While this theory is still debated, there is strong evidence to suggest that there are differences in the levels of certain chemicals in the brains of people with conditions such as depression and anxiety in comparison to those without.2 

This imbalance allows professionals some insight into how some level of stability can be restored.

SNRIs work by inhibiting the absorption of two brain chemicals, which are primarily responsible for mood, energy, arousal, and attention: serotonin and norepinephrine. To put it as simply as possible, SNRIs increase the availability of these chemicals, allowing them to continue signaling messages between the brain’s cells. 

This increased availability means that people with mental health conditions can start to feel more positive, alert, focused, and able to function.3 Additionally, people with chronic pain also tend to feel relief as a result. 

Although medications such as SNRIs may seem like the solution to your problems, they’re not the right fit for everyone. They also work best when combined with therapy, as this allows people to get to the root of their issues. 

What Are SNRIs Used For?

SNRIs are commonly prescribed for depression, but they’re also used for conditions such as anxiety, panic disorders, PTSD, and obsessive-compulsive disorder (OCD). Additionally, SNRIs have been shown to be effective in treating people with chronic pain issues, especially when this pain goes alongside a mental health condition.4 

It’s also not uncommon for SNRIs to be prescribed off-label for conditions they’re not approved for. Off-label prescribing happens frequently, and often when other treatment options haven’t worked out. 

The following information covers some of the common conditions SNRIs are used to treat.

SNRI for Depression

Depression is a condition that can vary in symptoms from mild to severe, and can seriously impact someone’s quality of life and well-being. While SSRIs are often the first go-to treatment for depression, recent studies have shown that SNRIs may be more effective at treating severe symptoms. For instance, SNRIs may work better for patients who have suicidal thoughts, need residential treatment, or haven’t responded to previous treatment.5 

SNRIs for Generalized Anxiety Disorder

Generalized anxiety disorder (GAD) can cause severe impacts on someone’s ability to function, as it’s characterized by intense worries about the past, present, and future. Along with SSRIs, SNRIs are first-line treatments for GAD and have been shown to work in helping people achieve relief of symptoms. For example, SNRIs such as duloxetine have been shown to be well tolerated and produce limited side effects while improving people’s quality of life.6 

SNRIs for Panic Disorder

Panic disorder consists of recurring, intense bouts of fear and panic, concern about future attacks, and avoidance of people and situations that could trigger them. SNRIs are first-line treatments for panic disorders, with evidence suggesting they’re as effective in treating episodes alongside SSRIs – especially venlafaxine

SNRI for Chronic Pain

As mentioned, SNRIs are often prescribed for treating chronic pain, such as chronic back pain, osteoarthritis, fibromyalgia, and neuropathic pain. Duloxetine, venlafaxine, and milnacipran are some of the SNRIs frequently prescribed for these conditions, as they have been shown to relieve symptoms.4

What Are Common SNRI Medications?

There is a wide variety of prescribed SNRI medications, but they don’t all work in the same way or produce the same side effects. For this reason, SNRIs vary in what they’re most commonly prescribed for. The following list covers the most common SNRIs and the conditions they’re used to treat. 

SNRI Medications List

It can feel overwhelming to be faced with medical names and descriptions, especially if you’re unsure what your diagnosis might be. A healthcare provider can discuss your symptoms with you and talk you through the most suitable medications for your needs. 

Your provider may also discuss initially treating your symptoms with an SSRI, so the next section discusses the similarities and differences between these two forms of medication.

SNRI vs SSRI Differences and Similarities

SNRIs and SSRIs are similar in a couple of ways. They’re both second-generation antidepressants and target the reuptake of serotonin, leading to improved mood, behavior, physical well-being, and overall outlook. Additionally, SSRIs and SNRIs cause the fewest side effects out of the available options of antidepressant medications. 

SSRIs tend to be the first port of call for providers when treating mental health issues, as they only target serotonin. But what if these don’t work? In this circumstance, the provider may consider targeting symptoms by switching someone to an SNRI. 

SNRIs may be more effective than SSRIs for providing symptom relief as they target serotonin and norepinephrine, so they also help to regulate sleep, attention, and memory. But with this wider ability to improve mental health issues comes an increased risk of side effects.
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For instance, certain SNRIs may not be appropriate for people with panic disorders or physical ailments due to the chance that they could induce feelings of panic, high blood pressure, and hyperalertness. We will discuss other SNRI side effects shortly.

When to Switch From SSRI to SNRI

Switching antidepressants comes up in the conversation with a mental health provider when there’s not enough of a response to treatment or too many undesirable side effects. 

As SSRIs only increase the availability of serotonin, they may not be enough for certain mental health symptoms. If this is the case, a provider may talk to you about the option of SNRIs, as they also target norepinephrine. However, SNRIs also come with an increased risk of side effects, so a provider will cautiously taper one medication before switching to another. This way, they can monitor your response and reduce the risk of serious side effects such as serotonin syndrome.
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SNRI Side Effects and Risks

All medications come with a risk of side effects, and SNRIs are no exception. With the exception of SSRIs, SNRIs tend to be the most well-tolerated antidepressant medication. However, everyone’s physiology differs; therefore, so too will their reaction to SNRIs. In other words, while one person might not encounter any side effects, others may experience one or more. 

For most people, side effects tend to ease after the adjustment period. However, for others, the side effects may persist. If this is the case, speak to your provider openly. They may adjust your dose or help you find a more suitable alternative. 

Common SNRI Side Effects:9

  • Gastrointestinal issues, such as nausea or stomach upset
  • Dry mouth
  • Perspiration 
  • Headaches
  • Dizziness
  • Fatigue
  • Constipation
  • Sleep difficulties
  • Appetite changes
  • Sexual dysfunction

For most people, the pros of SNRIs will outweigh the cons. However, in rare cases, they can cause a form of glaucoma in which pressure is raised inside the eye. Another less common side effect of SNRIs that needs to be considered with caution is how they can lead to raised blood pressure. SNRIs and blood pressure are closely monitored by a provider to manage any risk. 

Additionally, SNRIs are not typically prescribed for people with liver issues, as they can lower electrolyte levels.

Tapering Off SNRI Medications: How to Come Off Them Safely

SNRIs work to increase the availability of the chemicals serotonin and norepinephrine in the brain, so it takes time for the body to adjust to this increase. Similarly, it takes time for the body to get used to a reduction in these chemicals when someone decides to come off them. 

Therefore, tapering off SNRI medications is best done slowly and with professional supervision. When SNRIs are phased out instead of stopped suddenly, there’s a reduced risk of relapse of symptoms and SNRI withdrawal symptoms. A healthcare provider, such as Mission Connection, can discuss the most suitable plans based on your needs, dosage, and specific medication. 

Not everyone will get SNRI withdrawal symptoms, but it’s good to keep an eye out for the following so that you can consult your provider if you have any concerns.

SNRI Withdrawal Symptoms:10

  • Return of mental health symptoms
  • Dizziness
  • Sensory issues or brain “zaps”
  • Stomach cramps
  • Vivid dreams
  • Movement issues
  • Stomach discomfort
  • Flu-like symptoms, such as a runny nose or sneezing

Frequently Asked Questions About SNRIs

The information in this article so far has aimed to cover all the necessary information on SNRIs that you might need – but you might still have questions. For this reason, we provide some FAQs and responses to help clear up whether SNRIs are the right choice for you. 

What Are the Best SNRIs for Anxiety?

There may be no such thing as the “best” SNRI, as the most suitable one likely will come down to your specific symptoms, needs, and reaction to medication. However, venlafaxine, duloxetine, and desvenlafaxine are commonly prescribed to treat anxiety disorders. 

SNRIs and Weight Gain – What Is the Link?

Like other antidepressants, SNRIs can cause mild to moderate weight gain.11 However, this effect can vary depending on the person’s reaction to the medication. For instance, SNRIs and weight loss are also linked for some people in the short term, especially with duloxetine. If SNRIs and weight gain are a concern, a provider can help you create a healthy nutrition and lifestyle plan. 

Can SNRIs Interact With Other Medications?

SNRIs can interact negatively with other medications, especially antidepressants, as the combination could lead to serotonin syndrome. Additionally, combining certain natural alternatives to antidepressants, such as St.John’s Wort, can also contribute to too much serotonin in the brain. For this reason, it’s important to consult your provider before adding any substances to your intake while on SNRIs. 

Is It Safe to Consume Alcohol While Taking SNRIs?

Alcohol use while on SNRIs is not recommended due to how it can worsen side effects and reduce benefits. It could also lead to feelings of depression and drowsiness. 

Mission Connection: Comprehensive Mental Health and Antidepressant Support

When first considering medications for mental health symptoms, the options, benefits, and potential side effects can sound overwhelming. What if you make the wrong choice? What if medication doesn’t help? Will you encounter any serious side effects? Each of these concerns is valid – but you don’t have to navigate this decision alone. 

Mission Connection can guide you on the right choice of medication based on your symptoms, needs, and responses. We look beyond the surface to target the underlying causes of mental health concerns, combining medication with therapy for the best possible outcomes. 

Whether medication management or therapy packages are part of your treatment journey, our team can help you figure out the right approach and meet you where you need. If you’re ready to talk about Mission Connection’s treatment options or just have more questions to ask about medication, our team is here to help. Contact us today via phone call or fill out our confidential contact form.

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References

  1. Hillhouse, T. M., & Porter, J. H. (2015). A brief history of the development of antidepressant drugs: From monoamines to glutamate. Experimental and Clinical Psychopharmacology, 23(1), 1. https://doi.org/10.1037/a0038550
  2. Jauhar, S., Cowen, P. J., & Browning, M. (2023). Fifty years on: Serotonin and depression. Journal of Psychopharmacology, 37(3), 237. https://doi.org/10.1177/02698811231161813
  3. Fanelli, D., Weller, G., & Liu, H. (2021). New Serotonin-Norepinephrine Reuptake Inhibitors and Their Anesthetic and Analgesic Considerations. Neurology International, 13(4), 497. https://doi.org/10.3390/neurolint13040049
  4. Robinson, C., Dalal, S., Chitneni, A., Patil, A., Berger, A. A., Mahmood, S., Orhurhu, V., Kaye, A. D., & Hasoon, J. (2022). A Look at Commonly Utilized Serotonin Noradrenaline Reuptake Inhibitors (SNRIs) in Chronic Pain. Health Psychology Research, 10(2), 32309. https://doi.org/10.52965/001c.32309
  5. Bartova, L., Fugger, G., Dold, M., Kautzky, A., Fanelli, G., Zanardi, R., Albani, D., Weidenauer, A., Rujescu, D., Souery, D., Mendlewicz, J., Montgomery, S., Zohar, J., Fabbri, C., Serretti, A., & Kasper, S. (2023). Real-world characteristics of European patients receiving SNRIs as first-line treatment for major depressive disorder. Journal of Affective Disorders, 332, 105-114. https://doi.org/10.1016/j.jad.2023.03.068
  6. Garakani, A., Murrough, J. W., Freire, R. C., Thom, R. P., Larkin, K., Buono, F. D., & Iosifescu, D. V. (2020). Pharmacotherapy of Anxiety Disorders: Current and Emerging Treatment Options. Frontiers in Psychiatry, 11, 595584. https://doi.org/10.3389/fpsyt.2020.595584
  7. Medical News Today. (n.d.). SSRI vs. SNRI: Differences, how they work, and side effects. https://www.medicalnewstoday.com/articles/ssri-vs-snri
  8. Keks, N., Hope, J., & Keogh, S. (2016). Switching and stopping antidepressants. Australian Prescriber, 39(3), 76. https://doi.org/10.18773/austprescr.2016.039
  9. ayo Clinic Staff. (n.d.). Serotonin and norepinephrine reuptake inhibitors (SNRIs). Mayo Clinic. Retrieved May 20, 2025, from https://www.mayoclinic.org/diseases-conditions/depression/in-depth/snris/art-20044970
  10. Harvard Health Publishing. (n.d.). Going off antidepressants. Harvard Health. Retrieved May 20, 2025, from https://www.health.harvard.edu/diseases-and-conditions/going-off-antidepressants
  11. Ghusn, W., Bouchard, C., Frye, M. A., & Acosta, A. (2022). Weight-centric treatment of depression and chronic pain. Obesity Pillars, 3, 100025. https://doi.org/10.1016/j.obpill.2022.100025