This class of drugs is used to treat pain and a wide range of mental and behavioral disorders.
An SNRI is a serotonin and norepinephrine reuptake inhibitor, which is a group of antidepressant medications.
They're used to treat depression as well as anxiety, obsessive compulsive disorder (OCD), attention deficit hyperactivity disorder (ADHD), fibromyalgia, nerve pain, and other pain disorders.
SNRIs work by blocking the reabsorption (reuptake) of the brain chemicals serotonin and norepinephrine.
These medicines were first introduced in the mid-1990s.
Types of SNRIs
Some common SNRIs include:
- Pristiq (desvenlafaxine)
- Cymbalta (duloxetine)
- Savella (milnacipran)
- Effexor (venlafaxine)
- Fetzima (levomilnacipran)
SNRI Side Effects
Side effects of SNRIs may include:
- Dry mouth
- Anxiety or agitation
- Difficulty urinating
- Loss of appetite
- Reduced sexual desire, or problems with sexual arousal
Let your doctor know about all medical conditions you have before starting on an SNRI.
SNRIs can cause a rare problem called serotonin syndrome, which is characterized by dangerously high levels of serotonin.
Tell your doctor right away if you experience any of the following symptoms:
- Anxiety, agitation, confusion, or restlessness
- Severe sweating
- Lack of coordination
- Rapid heart rate
Antidepressants may raise the risk of suicidal thoughts or behaviors, especially in children, adolescents, and young adults. Talk to your doctor if this is a concern.
Some SNRIs can raise your blood pressure or worsen liver problems.
Tell your doctor about all prescription, non-prescription, illegal, recreational, herbal, nutritional, or dietary drugs you're taking before starting on an SNRI.
It may take several weeks or longer before you experience the benefits of an SNRI.
You may develop withdrawal symptoms if you stop taking an SNRI suddenly or miss several doses of the drug.
Symptoms of SNRI withdrawal can include:
- Urgent need to urinate
- Tiredness, chills, muscle aches, or other flu-like symptoms
Don't stop taking an SNRI without first talking to your doctor.
SNRIs and Alcohol
Alcohol may worsen certain side effects of SNRIs.
Avoid drinking alcohol while taking these medicines.
SNRIs and Pregnancy
Tell your doctor if you're pregnant or might become pregnant while taking an SNRI.
Pregnant women should avoid taking these medicines, but don't stop taking an SNRI without first talking to your doctor.
SNRIs can pass into breast milk. Talk to your healthcare provider before taking an SNRI if you're breastfeeding.
SNRI vs. SSRI
The selective serotonin reuptake inhibitor (SSRI) class is another group of antidepressants.
SSRIs block only the reuptake of serotonin, while SNRIs block the reuptake of both serotonin and norepinephrine.
Some studies have shown that SNRIs may have better pain-relieving properties, and may be more effective at treating certain forms of depression.
Other research has shown mixed results.
More data is needed to fully understand how these two types of antidepressants compare with one another.
Editorial Sources and Fact-Checking
- Serotonin and norepinephrine reuptake inhibitors (SNRIs), Mayo Clinic.
- Antidepressants, MedlinePlus.