posted
when adding a suffix to an acronym (acronym being used as a verb and getting a verb ending):
I must have OD'ed
or
I must have ODed
The apostrophe doesn't make sense to me, since you don't use an apostrophe for verb endings normally, but without it it looks like it's supposed to be one word (pronounced oh-dead).
posted
Webster's 11th Collegiate answers this one under OD, transitive verb, inflected forms, ODed or OD'd. In other inflected forms, OD'ing and OD's. He OD'd (ODed) on TV. He's OD'ing on TV. He OD's on TV every night.
Apostrophe rules also distinguish missing letters as in contractions, din't for didn't for did not, and like in OD'd, and when necessary for clarity with suffixes that might confuse meaning, especially with letters used as words. On the S level there are nine rooms named with S's.
[This message has been edited by extrinsic (edited July 25, 2009).]