Vanoxerine

Vanoxerine inhibits dopamine reuptake by binding and blocking the dopamine transporter. The use of vanoxerine has been evaluated as a potential substitute of cocaine in the treatment of drug addiction. In primates, the intravenous administration of vanoxerine reduced cocaine self-administration at 1 mg/kg and eliminated it at 3 mg/kg. The stimulant profile of cocaine was not detected in healthy volunteers (n=8) receiving vanoxerine for 2 weeks, suggesting a lack of abuse potential of vanoxerine. However, other studies have found that vanoxerine has at least moderate potential to be abused by humans. The antiarrhythmic potential of vanoxerine has also been assessed. A clinical study evaluating the efficacy of vanoxerine on the conversion of atrial fibrillation (AF) or atrial flutter (AFL) to normal sinus rhythm reported that, within 24 hours, a significant proportion of symptomatic AF/AFL patients treated with 200, 300 and 400 mg of vanoxerine converted to sinus rhythm. In studies that evaluated doses ranging from 25 to 300 mg, vanoxerine was considered to be safe and tolerable.

Vanoxerine is a highly selective dopamine transporter antagonist. Due to its ability to inhibit dopamine reuptake, it has been suggested that vanoxerine may be beneficial in treating cocaine addiction. Cocaine increases the amount of dopamine in the synapse by attaching and blocking the dopamine transporter. Compared to cocaine, vanoxerine has a higher affinity for the dopamine transporter and a slower dissociation rate, without the stimulant profile of cocaine. The use of vanoxerine to treat conditions characterized by low levels of dopamine, such as Parkinson's disease and depression, has also been investigated. Vanoxerine is also a potent blocker of the hKV11.1 (hERG) cardiac potassium channel. Even at low concentrations, vanoxerine is capable of blocking calcium and sodium currents without having a significant effect on QT interval, action potential waveforms and transmural dispersion of repolarization. Because of this, the anti-arrhythmic and anti-atrial fibrillatory properties of vanoxerine have been investigated.

_In vitro_ studies suggest that vanoxerine is mostly metabolized by CYP3A4. CYP2C8 and CYP2E1 may also contribute to the metabolism of this drug. CYP3A4 selective-inhibitors may interact with vanoxerine.

Vanoxerine has known human metabolites that include 1-Phenyl-3-[4-[2-(4,4'-difluorobenzhydryloxy)ethyl]piperazino]-1-propanol and 4-[3-[4-[2-[Bis(4-fluorophenyl)methoxy]ethyl]piperazino]propyl]phenol.

At doses of 25, 75 or 125 mg, vanoxerine had a corresponding Cmax of 17.9, 81.1 and 236.5 nmol/L and a corresponding AUC of 81, 365 and 1116 h⋅nmol/L when given orally to healthy male volunteers (n=14). In this same set of subjects, tmax was reached at 0.91, 0.93 and 1.13 h at oral doses of 25, 75 or 125 mg, respectively. The oral bioavailability of this drug depends on food intake. Compared with those fasting, the bioavailability of vanoxerine in volunteers taking a low-fat and a high-fat meal was 76% and 255% higher, respectively.

The majority of vanoxerine is excreted in urine, bile and feces.

Vanoxerine is capable of crossing the blood-brain barrier and distributing to several organs such as fat tissue, lungs, liver and the gastrointestinal tract. Vanoxerine has a large volume of distribution.

At 25, 75 and 125 mg/day, vanoxerine had a corresponding oral clearance of 660, 478 and 250 L/h.