GMDN Codes are not built into the Static UDI number allocated to your product and therefore changes to GMDN Terms will not require you to assign a new UDI to your product and the costly relabelling that would result.
As part of their implementation of UDI, the US FDA require manufacturers to submit a GMDN Code that is not obsolete, when you provide your product information as part of the GUDID record submission. We have been informed by the FDA that it is possible to change the GMDN Code allocated to a product on the GUDID at any time, because the GMDN record is not ‘locked’ unlike other information, such as the Static UDI number.