What are Serotonin and Norepinephrine Reuptake Inhibitors (SNRIs)?

Serotonin and norepinephrine reuptake inhibitors (SNRIs) are a class of antidepressant medications that have been approved by the FDA and are commonly used to help treat depression. SNRIs may also be used to treat anxiety, chronic pain, and nerve pain. SNRIs work by affecting brain chemistry and changing the communication in brain nerve cell circuitry responsible for regulating mood.

Use Cases of SNRIs for Mental Health Disorders

SNRIs are typically prescribed to help treat or manage symptoms of depression. SNRIs may also be used to treat the following conditions:

• Generalized anxiety disorder
• Social anxiety disorder
• Panic disorder
• Fibromyalgia
• Pain from diabetes-related neuropathy
• Musculoskeletal pain

Which Drugs are SNRIs?

There are several FDA-approved SNRIs.

They include:

• Desvenlafaxine (Khedezla®, Pristiq®)
• Duloxetine (Cymbalta®, Drizalma®, Irenka®)
• Levomilnacipran (Fetzima®)
• Venlafaxine (Effexor®)
• Milnacipran (Savella®)

Side Effects

There are several different potential side effects that may occur while using an SNRI. Side effects vary between individuals. Not everyone who takes an SNRI experiences side effects. The most common side effects include:

• Headache
• Anxiety or agitation
• Tremors
• Difficulty with sleep
• Dry mouth
• Tachycardia (elevated heart rate)
• Heart palpitations
• Dizziness
• Nausea
• Lack of appetite
• Constipation
• Muscle weakness
• Excessive sweating
• Difficulty urinating
• Fluid retention (mostly in older adults)
• Sexual dysfunction in males

The benefits of taking an SNRI usually outweigh the possible side effects. Consult with your healthcare provider to see what may work best for you.

Types of SNRIs

There are several FDA-approved SNRIs. They include:

• Desvenlafaxine (Khedezla®, Pristiq®)
• Duloxetine (Cymbalta®, Drizalma®, Irenka®)
• Levomilnacipran (Fetzima®)
• Venlafaxine (Effexor®)
• Milnacipran (Savella®)

How SNRIs Work

SNRIs work by blocking the reabsorption (reuptake) of the neurotransmitters of serotonin and norepinephrine in the brain. This allows serotonin and norepinephrine levels to increase and remain active in the brain. Both neurotransmitters work as chemical messengers in the brain. Serotonin plays a role in mood regulation, the sleep-wake cycle, and memory. It can also impact your appetite, digestion, social behavior, and sexual desire. Norepinephrine plays a role in increasing energy levels, attention and focus, alertness, and arousal.

Precautions and Warnings

Although SNRIs are safe for most people, they do carry some precautions and warnings. Common precautions and warnings of certain SNRIs include:

• May raise blood pressure
• May worsen liver problems
• Harmful drug interactions (certain medications or herbal supplements may be harmful if taken with the SNRIs)
• Serotonin syndrome (this happens in rare cases, but will need immediate medical attention)
• Antidepressants during pregnancy or while breastfeeding may be harmful to the baby

It is important to consult with your healthcare provider about the possible risks if you are taking an antidepressant and considering getting pregnant. Please do not stop taking your medication without consulting your healthcare provider first. Stopping medication may pose a risk for you.

Suicide Risk with Antidepressants

Most antidepressants are considered safe. However, the FDA requires all antidepressants to carry a black box warning label. The reasoning for this is that in some cases, children, teenagers, and young adults under the age of 25 may have an increased risk for suicidal thoughts and behaviors when taking antidepressants. Within the first few weeks of starting an antidepressant or when the dosage is changed seems to be when the greatest potential for suicidal thoughts or behaviors would occur.

It is important to keep in mind that antidepressants are meant to regulate mood and decrease symptoms of depression, which would help to reduce the risk of suicide in the long-term.

Call to Schedule an Appointment

If you are noticing symptoms of depression, please consult with your healthcare provider to determine what your next steps should be. Your healthcare provider will also answer any questions you may have about antidepressants.

Call a Baptist Health provider to schedule an today.