Selective Serotonin and Norepinephrine Reuptake Inhibitors (SNRIs) increase the levels of two brain chemicals — serotonin and norepinephrine — in the synapses between brain cells. As with SSRIs, the full mechanism of action of SNRIs is poorly understood. But researchers know that, like serotonin, norepinephrine plays an important role in regulating mood and anxiety. It also contributes to regulating alertness and concentration.
Check out the following table for a list of the most common SNRIs available and the potential side effects for each one.
| Generic Name | Brand Name | Average Adult Dose | Potential Benefits | Some Possible Side Effects* |
|---|---|---|---|---|
| Desvenlafaxine | Pristiq | 50 to 100 mg/day | Antidepressant (approved for use in unipolar depression). Also used to treat many anxiety disorders, but this can present challenges in someone with bipolar disorder. | Suicidal ideation; agitation; disinhibition; mania; insomnia; sedation; elevated blood pressure; change in sexual function; nausea or diarrhea; weight gain. |
| Duloxetine | Cymbalta | 60 to 120 mg/day | Antidepressant (approved for use in unipolar depression). Also used to treat many anxiety disorders, but this can present challenges in someone with bipolar disorder. Treats some pain syndromes. | Suicidal ideation; agitation; disinhibition; mania; insomnia; sedation; elevated blood pressure; change in sexual function; nausea or diarrhea; weight gain; affects the liver, so alcohol intake should be limited. |
| Venlafaxine | Effexor Effexor XR |
75 to 375 mg/day; 75 to 225 mg/day (extended release) | Antidepressant (approved for use in unipolar depression). Also used to treat many anxiety disorders, but this can present challenges in someone with bipolar disorder. | Suicidal ideation; agitation; disinhibition; mania; insomnia; sedation; elevated blood pressure; change in sexual function; nausea or diarrhea; weight gain; has severe withdrawal symptoms with missed doses. |
mg/day = milligrams per day.
* Other side effects may occur that aren't listed.
SNRIs may take several weeks to become fully effective, so keep taking the medication even if you don't experience immediate relief.
