The large majority of items are prescribed through general practices (mostly but not exclusively by GPs) and statistics are mainly focussed on these items.
Caiff y rhan fwyaf o'r eitemau eu rhagnodir drwy bractisau meddygon teulu (gan feddygon teulu gan amlaf, ond nid ganddyn nhw yn unig) ac mae'r ystadegau'n canolbwyntio'n bennaf ar yr eitemau hyn.