WSDD is the key map to other drug and prescribing sources including:
Read (all versions),
ICD9,
ICD10,
OPCS4,
SnomedCT,
British National Formulary codes,
Martindale coding,
APBI SPCs (Datasheets) and Patient Information Leaflets (PILs),
PIP codes (plus a variety of other pharmaceutical product codes),
PPA codes,
EAN numbers,
NDC codes
ATC codes (both W.H.O. and EPhMRA versions),
and full mapping to the NHS dictionary of medicines and devices (dm+d)