SNRIs

SNRIs (Serotonin/Noradrenaline Reuptake Inhibitors) are a relatively new group of antidepressants that have proved to be an effective, safe form of treatment for patients with anxiety disorders but without comorbid major depression. They are not effective in OCD. These drugs include:

• duloxetine
• venlafaxine XR
• in a few countries - milnacipram 

SNRIs also have effects on the noradrenaline and serotonin neurotransmission system, which appear to be important in mood and anxiety disorders. The potentially troublesome side effects are slightly more pronounced than those of the SSRIs as these also include the noradrenergic side effects:  These may include:

• restlessness and agitation
• difficulty in sleeping
• dryness of the mouth
• nausea and vomiting
• headache
• constipation
• tendency to sweat
• sexual problems (lack of desire, delayed/absent ejaculation)
• weight increase
• vision disturbance
• palpitations
• blood pressure increase

Both the SSRIs and the SNRIs are new drugs, which, because of their specificity for the serotonin and noradrenaline reuptake proteins, lack most of the adverse side effects of the older antidepressants. Consequently, in addition to being first-line treatments for major depression, they are also first-line for panic disorder, obsessive-compulsive disorder, social phobia, posttraumatic stress disorder, and bulimia. They may also be the best medication treatment for generalized anxiety disorder.