I’m in Canada. My wife took Domperidone for a few weeks after her Whipple surgery, to help with a problem called “delayed stomach emptying”. It’s a common issue after Whipple. She still occasionally needs Domperidone, when she feels like her stomach is “filled with stones” (her words).
My understanding is that Domperidone can also be used for nausea. Our doctors never told us to use Domperidone for that purpose.
For chemo-induced nausea, my wife took Zofran and Stemetil (Compazine). Zofran twice a day as the main anti-nausea medication. Stemetil (Compazine) in between Zofran on as needed basis, to deal with break-through nausea.
EDIT:
My question to you is, why was Reglan prescribed to your son? Is it for nausea?