High Quality Content by WIKIPEDIA articles! This is a list of abbreviations used in medical prescriptions (sometimes referred to as sig codes). This listing does not include abbreviations for actual pharmaceuticals (which is a separate article in itself). Capitalization and the use of periods is a matter of style. In the attached list, Latin is not capitalized whereas English acronyms are. The period is used wherever there are letters omitted in the abbreviation. Abbreviations which are officially not to be used as required by the Joint Commission are marked in red. Those abbreviations which are discouraged from use by other organizations are marked in orange.