Serotonin-norepinephrine reuptake inhibitors (SNRIs) are commonly used to treat depression and a variety of other conditions like anxiety and chronic pain. In this video, I discuss how SNRIs work in the brain and how they are proposed to be able to treat the symptoms of depression.
The controversy about the relative efficacy of different types of antidepressants continues in part because there are numerous problems that
limit the sensitivity of RCTs to detect efficacy differences between
The backlash against antidepressants results from a suspicion of medicine, and misunderstands the very nature of depression.
While these drugs are traditionally considered a group of inter-related antidepressants based upon reuptake inhibition, they generally display different chemical structures as well as different pharmacological properties.
Also known as dual-uptake inhibitors, serotonin and norepinephrine reuptake inhibitors (SNRIs) are commonly prescribed by physicians and psychiatrists to treat depression and anxiety. SNRIs, developed in the mid-1990s, are very similar to another category of antidepressants known as selective serotonin reuptake inhibitors (SSRIs), but they have a slightly broader effect on chemical processes in the brain, and some individuals who do not respond to SSRIs may benefit from an SNRI.
SSRIs are more commonly prescribed, as they have been around longer and usually have less risk of causing side effects. However, SNRIs can sometimes be more effective than SSRIs.
The first SNRIs were introduced in the mid-1990s, with venlafaxine (sold as Effexor®) approved by the FDA in 1993.
Like other antidepressants, SNRIs work by increasing the levels of neurotransmitters, which are chemicals related to your thoughts, feelings and moods.
SNRIs are also used to treat other conditions such as anxiety disorders and chronic pain associated with diabetic neuropathy or fibromyalgia. SNRIs may be prescribed if you have a coexisting condition like neuropathic pain in addition to depression.
The answer is: the effect of SNRIs (serotonin norepinephrine reuptake inhibitors) on anxiety disorders has nothing to do with norepinephrine. The antidepressants which are effective for anxiety disorders have strong effects on the serotonin neurotransmitter, whereas the dual action of SNRIs on serotonin and norepinephrine appear to be slightly more effective than SSRIs (selective serotonin reuptake inhibitors) for the treatment of depression (Papakostas et al., 2007).
SNRIs, like other depression medicines, can take several weeks to work. It takes time for the brain to produce enough neurochemicals for the patient to feel a noticeable reduction in depression symptoms. SNRIs are particularly effective for depression patients who also suffer from chronic nerve pain.