Serotonin-norepinephrine reuptake inhibitors (SNRIs) are a class of medications that are primarily used as antidepressants. They work by blocking the reuptake of both serotonin and norepinephrine in the brain, increasing the levels of these neurotransmitters and thereby improving mood and reducing symptoms of depression.


SNRIs work by inhibiting the reuptake of both serotonin and norepinephrine in the brain. Serotonin is a neurotransmitter that helps regulate mood, appetite, and sleep, while norepinephrine is involved in the body’s stress response. By blocking their reuptake, SNRIs increase the levels of these neurotransmitters in the brain, which can help alleviate symptoms of depression.


SNRIs are primarily prescribed for the treatment of major depressive disorder (MDD). They may also be used to treat other mood disorders, such as generalized anxiety disorder (GAD) and panic disorder. In some cases, SNRIs may be used off-label to manage chronic pain conditions, such as fibromyalgia or neuropathy, due to their ability to modulate pain signals in the brain.

Mechanism of Action

The mechanism of action of SNRIs involves blocking the reuptake of serotonin and norepinephrine in the brain. By inhibiting the reuptake process, these medications increase the concentration of these neurotransmitters in the synapses, which enhances signal transmission and communication between nerve cells. This modulation of neurotransmitter levels helps restore balance and improve mood regulation.

Side Effects

Just like any medication, SNRIs can cause side effects. Common side effects include nausea, dizziness, headache, insomnia, fatigue, and sexual dysfunction. These side effects are usually temporary and may subside over time. However, it is important to discuss any persistent or severe side effects with a healthcare provider.

Examples of SNRIs

Some commonly prescribed SNRIs include venlafaxine (Effexor), duloxetine (Cymbalta), and desvenlafaxine (Pristiq). These medications are available in different dosages and formats (tablets, capsules) and are typically taken once or twice daily, as directed by a healthcare professional.