Handy device prescribed by the doctor? (6)
I believe the answer is:
tablet
This clue is a double definition.
'handy device' is the first definition.
(type of hand-held device)
'prescribed by the doctor?' is the second definition.
(a doctor might prescribe tablets)
(Other definitions for tablet that I've seen before include "Pill; writing pad" , "Small slab or flat pill" , "Let bat provide a pill" , "Battle (anag) - pill" , "Flat slab (of stone, etc)" .)