Be aware that being in unfamiliar surroundings is likely to increase the person with dementia’s sense of confusion and agitation, which could lead to aggressive behaviour.
If accompanied by a relative/friend who they know and trust, ensure the relative/friend stays with them throughout their treatment.
Follow general advice.
If possible find a quiet area to place them and speed up the process so they are seen as quickly as possible.
As they may not be able to tell you about their pain, consider pain relief as early as possible, if this is appropriate.