What Causes Involuntary Tremors In Right Extremities And Unsteady Gait?
If Metoclopramide used, most likely Tardive dyskinesia.
Detailed Answer:
Hello and thanks for using HCM.
I have read your query and understand your concerns.
There is one thing to clarify about your mother's past treatment, did she used Metoclopramide during chemotherapy to prevent vomiting?
If so, then movement disorders you describe are most probably a late side effect of Metoclopramide or Tardive dyskinesia and Benadryl is used as a treatment possibility to improve this condition.
If no use of Metoclopramide, then symptoms and movement disorders you describe could be the start of extrapiramidal ( or basal ganglia) disorders such, dystonia, Parkinson's etc.
Hope this helps. I remain at your disposal for further questions and clarifications.
Take care.