Home Depression Medications Reference Guide to Serotonin and Norepinephrine Reuptake Inhibitors (SNRIs)

Reference Guide to Serotonin and Norepinephrine Reuptake Inhibitors (SNRIs)

by Alli Hill
woman enjoying the outdoors


  • Serotonin and norepinephrine reuptake inhibitors (SNRIs) are used to treat various mental health disorders, including depression, major depressive disorder, and generalized anxiety disorder.
  • SNRIs are unique in that they target two types of neurotransmitters: serotonin and norepinephrine.
  • SNRIs and other antidepressants may increase suicidal thoughts and behaviors, especially in adolescents and young adults.
  • SNRIs are generally safe but may not be right for everyone.
  • This guide to SNRIs explores potential interactions with other medications, such as MAOIs, amphetamines, blood thinners, and antiarrhythmics.

Many people experience sadness or irritability. But when these feelings don’t dissipate over time or interfere with your daily life, there might be more going on beneath the surface. Depression is a reality for more than 280 million people worldwide, and medications like serotonin and norepinephrine reuptake inhibitors (SNRIs) provide relief.

When depressive symptoms don’t go away on their own, prescription medications can help individuals live a normal life. These medications work by balancing chemicals in the brain that contribute to feelings of happiness and mood regulation.

Learn more in this guide to SNRIs and what to expect if your doctor prescribes an SNRI to treat your depression. 

What Are SNRIs?

SNRIs are a type of antidepressant that treat various mental health disorders. They are a common prescription in the United States.

Examples of conditions SNRIs can treat include:

  • Depression
  • Major depressive disorder (MDD)
  • Generalized anxiety disorder (GAD)
  • Social anxiety disorder
  • Panic disorder
  • Some chronic pain conditions, such as nerve pain

Off-label uses for SNRIs may include:

  • Hot flashes
  • Night sweats
  • Urinary incontinence
  • Peripheral neuropathy
  • Attention deficit/hyperactivity disorder (ADHD)
  • Migraines
  • Obsessive-compulsive disorder (OCD)

How Do SNRIs Work?

SNRIs work by affecting the neurotransmitters in the brain, specifically serotonin and norepinephrine. Neurotransmitters are chemical messengers that aid communication between nerve cells. These two neurotransmitters play a role in regulating mood, emotions, and perceptions of pain, which is why they’re commonly used to treat depression.

The neurotransmitters deliver messages in the brain. When the “mission” is complete, they are reabsorbed by the nerve cells that released them — a process called reuptake.

It’s theorized that depression occurs when neurotransmitters like serotonin, norepinephrine, or dopamine are depleted in the brain. There’s simply not enough to keep you feeling happy.  

potential candidate for serotonin

By inhibiting the reuptake process, more neurotransmitters are available in the brain, helping to stabilize moods and positive feelings.

SNRIs inhibit the reuptake of serotonin and norepinephrine. This increases the amount of each neurotransmitter in the brain, which improves communication between nerve cells. By better balancing these chemicals, antidepressants have a positive impact on emotions and well-being.

Description and Examples of SNRIs

SNRIs are one of several subtypes of antidepressants, which also include selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs). 

Examples of SNRIs include:

SNRIs are unique because of the neurotransmitters they target. Unlike SSRIs, which focus on serotonin, SNRIs also target norepinephrine. TCAs affect serotonin, norepinephrine, and other neurotransmitters as well. 

woman taking SNRIs

Treatment and use cases can also vary. While SSRIs are mainly used to treat depression, SNRIs can treat depression and anxiety disorders. TCAs have a still broader range of uses.

Ultimately, the choice of antidepressants depends on several factors, including:

  • The patient’s specific condition(s)
  • Medical history
  • Potential side effects
  • Response to previous treatments

Your doctor will conduct a thorough evaluation of your health history and symptoms prior to recommending an antidepressant.

Warnings and Contraindications — SNRIs

While generally safe and effective, SNRIs come with warnings and contraindications that should be considered before taking these medications. Warnings and contraindications may vary by prescription. 


Common warnings with SNRIs include the following:

  • Suicidal thoughts. SNRIs are known to increase the risk of suicidal thoughts and behaviors, especially in adolescents and young adults. Report any suicidal feelings or behaviors to your doctor immediately.
  • Serotonin syndrome. SNRIs increase serotonin levels in the brain, which could lead to the development of serotonin syndrome, a rare but serious condition. Symptoms include:
    • Sweating
    • Fever
    • Confusion
    • Stiff muscles
    • Seizures
  • Antidepressant discontinuation syndrome. Missing doses or abruptly discontinuing your medication may create unwanted side effects, such as dizziness, nausea, or insomnia. Never stop an antidepressant on your own; these medications require a gradual taper done under a doctor’s supervision.

woman experiencing a headache

Additional warnings may exist for individual SNRI medications. For example, mydriasis has occurred in patients with narrow-angle glaucoma who were taking desvenlafaxine. This medication features additional warnings for patients with:

  • Elevated blood pressure
  • Abnormal bleeding
  • Hypomania
  • Cardiovascular disease
  • High cholesterol
  • Renal impairment
  • Seizures
  • Hyponatremia
  • Interstitial lung disease

Speak with your doctor to learn more about the risks and benefits of your specific medication.


SNRIs are typically contraindicated in patients:

  • Who have a known hypersensitivity to the drug
  • Are taking an MAOI
  • Have stopped taking an MAOI within the previous 14 days

This information is not a substitute for professional medical advice. Always consult with your doctor prior to taking any medication, including SNRIs. They can discuss the individual risks and benefits of a specific SNRI and provide guidance on its safe and effective use based on your personal medical history.

Side Effects — SNRIs

Side effects may vary between individuals and medications. Some of the most common side effects of SNRIs include:

  • Nausea
  • Vomiting
  • Dry mouth
  • Dizziness
  • Headache
  • Fatigue
  • Constipation
  • Insomnia
  • Decreased libido
  • Loss of appetite
  • Heartburn
  • Weight changes
  • Nervousness

Rare but serious side effects should be reported to your doctor. These include but are not limited to:

  • Abnormal bleeding
  • Rash
  • Hives
  • Swelling
  • Difficulty breathing
  • Seizures
  • Hallucinations
  • Confusion
  • Difficulty swallowing
  • Loss of coordination
  • Itching
  • Chest pain

Drug Interactions — SNRIs

SNRIs may interact with other medications, and some medications should never be taken together. Interactions can vary by prescription, so be sure all your providers know every medication and over-the-counter supplement you’re currently taking to avoid potential interactions. 

pills and pill bottles

Typically, SNRIs should not be taken with the following types of medications:

  • Amphetamines. SNRIs may increase the effects of amphetamines, including jitteriness, nervousness, and anxiety, and may lead to serotonin syndrome.
  • MAOIs. Taking these two types of drugs may lead to serotonin syndrome.
  • TCAs.Using SNRIs with tricyclic antidepressants (TCAs) may increase the risk of heart problems and serotonin syndrome. 
  • Blood thinners. Warfarin and NSAIDs may increase the risk of bleeding.
  • Antiarrhythmic drugs. This combination may increase the risk of an irregular heartbeat that can be serious and potentially life-threatening.

For a complete list of potential interactions, check your medication using the Drug Interaction Checker.

Are SNRIs the Right Option for Your Depression?

SNRIs have been shown to be highly effective in treating certain depressive disorders. They target two unique neurotransmitters, serotonin and norepinephrine, to increase their availability in the brain. For many patients, SNRIs allow them to lead happy and productive lives.

However, no medication is without risk. It’s important to review the potential side effects, warnings, and contraindications prior to taking any medication. Let your doctor know all of the prescriptions, over-the-counter medications, and supplements you’re taking to avoid potential adverse effects.

Get the Lowest Price for Your SNRIs

If you’re looking to save money on SNRIs or other medications, BidRx can help. Create a free account, share your prescription, and let pharmacies compete for your business. You can select the offer that best matches your budget and have your prescriptions delivered to your door.

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This information is intended for general informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or medication. 

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