Viloxazine

Viloxazine (Emovit&reg;, Vivalan&reg;, Vivarint&reg;, Vicilan&reg;) is a bicyclic antidepressant morpholine derivative that inhibits the reuptake of norepinephrine. It is a racemic compound with two isomers, the S(-)-isomer being five times as pharmacologically active as the R(+)-isomer.

Approved
Viloxazine hydrochloride was approved in Italy, Belgium, the United States, England, Ireland, Germany, Portugal, Spain, the former Yugoslavia, France, Slovakia, for the treatment of clinical depression.

Unapproved/off-Label/investigational
Viloxazine has undergone two randomized controlled trials for nocturnal enuresis (bed-wetting) in children, both of those times versus imipramine., By 1990, it was seen as a less cardiotoxic alternative to imipramine, and to be especially effective in heavy sleepers.

In narcolepsy, viloxazine has been shown to suppress auxiliary symptoms such as cataplexy and also abnormal sleep-onset REM without really improving daytime somnolence.

Viloxazine has also been studied for the treatment of alcoholism, with some success.

While viloxazine may be effective in clinical depression, it did relatively poorly in a double-blind randomized controlled trial versus amisulpride in the treatment of dysthymia, according to Leon and colleagues at the University of Valle in Colombia.

Mechanism of action
In 1976, Lippman and Pugsley reported that viloxazine, like imipramine, inhibited norepinephrine reuptake in the hearts of rats and mice; unlike imipramine, (or desipramine or amitriptyline, for that matter) it did not block reuptake of norepinephrine in neither the medullae nor the hypothalami of rats. As for serotonin, while its reuptake inhibition was comparable to that of desipramine (i.e., very weak), viloxazine did potentiate serotonin-mediated brain functions in a manner similar to amitriptyline and imipramine, which are relatively potent inhibitors of serotonin reuptake. Unlike any of the other drugs tested, it did not exhibit any anticholinergic effects.

It is also known to up-regulate GABAB receptors in the frontal cortex.

Side effects
Side effects include nausea, vomiting, insomnia, loss of appetite, increased erythrocyte sedimentation, EKG and EEG anomalies, epigastric pain, diarrhea, constipation, vertigo, orthostatic hypotension, edema of the lower extremities, dysarthria, tremor, psychomotor agitation, mental confusion, inappropriate secretion of antidiuretic hormone, increased transaminases, seizure, (there were three cases worldwide, and most animal studies (and clinical trials that included epilepsy patients) indicated the presence of anticonvulsant properties, so is not completely contraindicated in epilepsy), and increased libido.

Drug interactions
Viloxazine is known to increase plasma levels of phenytoin by an average of 37%. It is also known to significantly increase plasma levels of theophylline and decrease its clearance from the body, sometimes resulting in accidental overdose of theophylline.