Radafaxine is drug

Drug

A drug, broadly speaking, is any substance that, when absorbed into the body of a living organism, alters normal bodily function. There is no single, precise definition, as there are different meanings in drug control law, government regulations, medicine, and colloquial usage.In pharmacology, a...

 candidate designated GW-353,162 by GlaxoSmithKline

GlaxoSmithKline

GlaxoSmithKline plc is a global pharmaceutical, biologics, vaccines and consumer healthcare company headquartered in London, United Kingdom...

, investigated for treatment of restless leg syndrome and as an NDRI antidepressant. GlaxoSmithKline was targeting Radafaxine for regulatory filing in 2007, but development was discontinued in 2006 due to "poor test results".

Chemistry

It is a potent metabolite of bupropion, the compound in GlaxoSmithKline's Wellbutrin. More specifically, "6-hydroxybupropion" is an analogue of bupropion, and radafaxine is an isolated isomer of 6-hydroxybupropion.

Therefore, radafaxine builds on at least some of the properties of bupropion in humans.

Effects

In various clinical trials, radafaxine has been studied as a treatment for clinical depression

Clinical depression

Major depressive disorder is a mental disorder characterized by an all-encompassing low mood accompanied by low self-esteem, and by loss of interest or pleasure in normally enjoyable activities...

, obesity

Obesity

Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...

, and neuropathic pain. Radafaxine is described as a norepinephrine-dopamine reuptake inhibitor

Norepinephrine-dopamine reuptake inhibitor

A norepinephrine-dopamine reuptake inhibitor is a drug which acts as a reuptake inhibitor for the neurotransmitters norepinephrine and dopamine by blocking the action of the norepinephrine transporter and the dopamine transporter , respectively...

 (NDRI).

Unlike bupropion

Bupropion

Bupropion is an atypical antidepressant and smoking cessation aid. The drug is a non-tricyclic antidepressant and differs from most commonly prescribed antidepressants such as SSRIs, as its primary pharmacological action is thought to be norepinephrine-dopamine reuptake inhibition...

 (which has a slightly higher effect on dopamine

Dopamine

Dopamine is a catecholamine neurotransmitter present in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this substituted phenethylamine functions as a neurotransmitter, activating the five known types of dopamine receptors—D1, D2, D3, D4, and D5—and their...

 reuptake

Reuptake

Reuptake, or re-uptake, is the reabsorption of a neurotransmitter by a neurotransmitter transporter of a pre-synaptic neuron after it has performed its function of transmitting a neural impulse....

), radafaxine seems to have a higher potency on norepinephrine

Norepinephrine

Norepinephrine is the US name for noradrenaline , a catecholamine with multiple roles including as a hormone and a neurotransmitter...

. This, according to GlaxoSmithKline, may account for the increased effect of radafaxine on pain

Pain

Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...

 and fatigue.

Radafaxine has about 70% of bupropion's efficacy in blocking dopamine reuptake, and 392% of efficacy in blocking norepinephrine reuptake.

At least one study suggests that radafaxine has a low abuse

Drug abuse

Substance abuse, also known as drug abuse, refers to a maladaptive pattern of use of a substance that is not considered dependent. The term "drug abuse" does not exclude dependency, but is otherwise used in a similar manner in nonmedical contexts...

potential similar to bupropion.