Home > Serotonin-norepinephrine reuptake inhibitor

Depression is thought to be caused by a lack of information flow between neurons in certain parts of the brain. Neurons pass information to each other by means of chemicals known as neurotransmitters, which shoot across the tiny synapses between the cells. After firing, most of the neurotransmitter is reabsorbed by the presynaptic cell in a process called reuptake.

Antidepressants work by increasing the amount of neurotransmitters active in the synapse, thereby enhancing neuronal activity and increasing the responsiveness of mood. Modern antidepressants usually achieve this effect by blocking the transporter proteins that reabsorb certain neurotranmitters, hence the name "reuptake inhibitors".

SNRIs were developed more recently than SSRIs, and there are relatively few of them. Their efficacy as well as their tolerability appears to be somewhat better than the SSRIs, owing to their compound effect. It is expected that most future antidepressants will probably work on multiple neurotransmitters, like the SNRIs and novel antidepressants such as bupropion (tradename Wellbutrin®).

SNRIs currently available:

• VenlafaxineVenlafaxine hydrochloride is a prescription antidepressant first introduced by Wyeth in 1993, and marketed under the tradename Effexor . It is used primarily for the treatment of depression, generalized anxiety disorder, and social anxiety disorder in adu (tradename Effexor®) is the first and most commonly used SNRI. Although it also works on dopamineDopamine is a neurotransmitter in the brain. As a member of the catecholamine family, dopamine is a precursor to epinephrine ( adrenaline) and norepinephrine ( noradrenaline) in the biosynthetic pathways for these neurotransmitters. Dopamine is synthesize somewhat at high dosages, the majority of its effect is on serotonin and norepinephrine.

• Nefazodone (tradename Serzone®) is an antidepressant with efficacy similar to SSRIs. It has been discontinued in several countries due to rare cases of unexpected liverThe liver is an organ in vertebrates including humans. It plays a major role in metabolism and has a number of functions in the body including detoxification, glycogen storage and plasma protein synthesis. It also produces bile which is important for dige failure.

• Milnacipran (tradename Ixel®) has shown to be significantly effective in the treatment of depression and Fibromyalgia syndromeFibromyalgia is a debilitating chronic illness characterized by diffuse pain, fatigue, and a wide range of other symptoms. It is a syndrome, not a disease. It is not contagious, and is probably genetic. It affects more women than men, mostly between ages (FMS). Although it has not yet been approved by the FDA for use in the United States, it has been commercially available in Europe and Asia for several years.

• Desipramine (tradenames Norpramine®, Pertofraneis®) is technically a tricyclic antidepressantChemical structure of the tricyclic antidepressant amitriptyline Tricyclic antidepressants are a class of antidepressant drugs first used in the 1950s. They are named after the drugs' molecular structure, which contains three rings of atoms (compare tetra, and is usually categorized as such. It works, however, on both serotonin and norepinephrine, so it can also be considered an SNRI.

• DuloxetineDuloxetine hydrochloride (brand name: Cymbalta is a medically used drug that primarily targets major depressive disorders (MDD) and stress urinary incontinence (SUI). Known also as LY248686, chemically (+ S N methyl-3-(1-napthalenyloxy)-2-thiophenepropana (tradename Cymbalta®) is a new SNRI by Eli Lilly and Company, and has been approved for the treatment of depression in August of 2004.