Possible Clues:

• Email dupes
• ER units
• They're equivalent to mLs
• Keeps apprised, for short
• Mails a dupe to
• Engine units: Abbr
• Duplicates, briefly ... and a hint to 16-, 22-, 49- and 58-Across
• Includes in an email's recipients
• Alternative to fl. oz
• Hospital IV amts