It is impossible to say which of these medications, if any, would help with any particular individual's shyness. Everybody's body chemistry is different. Medications may seem to work at first and then stop. Or they may require larger and larger doses to have the same effect. Or new side effects may crop up after a few months of usage.
Medications are also limited in what they can do.
They may help throttle back the nervousness that often accompanies shyness. But they may do nothing to help increase self confidence, remove nervous mannerisms, or alter the other symptoms of shyness.