is basically brand name for a psychostimulant belonging to phenethylamine and amphetamine
It is thought to work by increasing the amount of dopamine
and norepinephrine in between synapses in the brain because the drug is a potent dopamine reuptake inhibitor and norepinephrine reuptake inhibitor
. It is available in two formulations: IR (Instant Release) and XR (Extended Release).
And this norepinephrine is a potent vasoconstrictor which may be a cause of your symptoms leading to bad circulation, numbness
And I would suggest that you should ask your doctor who prescribed you this medicine and if you are taking it by yourself you should stop it keeping in view your side-effects.
I hope this this answered your query.