Doesn't work? 
$ echo "12345Red6789" | perl -ape 's/[\s\(]+(r|rd|red)[\s\)]+//gi;'
12345Red6789

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The OP said the spaces were optional.

In reply to Re^2: RegEx to match at least one non-adjacent term by ikegami
in thread RegEx to match at least one non-adjacent term by Cefu

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