"A 60-year-old man with acute pancreatitis developed persistent hiccups after insertion of a nasogastric tube. Removal of the latter did not terminate the hiccups which had also been treated with different drugs, and several maneuvers were attempted, but with no success. Digital rectal massage was then performed resulting in abrupt cessation of the hiccups. [1]"Recurrence of the hiccups occurred several hours later, and again, they were terminated immediately with digital rectal massage. No other recurrences were observed. This is the second reported case associating cessation of intractable hiccups with digital rectal massage. We suggest that this maneuver should be considered in cases of intractable hiccups before proceeding with pharmacological agents."
So. Instead of using medicine, you should stick your finger in your butt. That sounds like good advice. Though they use the term "rectal massage." I wonder what happens if they accidentally hit the prostate while massaging that rectum? I know that would make me gasp some air. If nothing else, it could make the hiccup cure more enjoyable, at least for men.
The problem I see here: how can one treat their hiccups during the workday? You can't just stick your finger in your butt whenever the need arises, can you? I think one of those remote control vibrators might be the answer. You would want one that does not make too much noise, of course. And position it carefully -- you also wouldn't want to be tickling that prostate while you're at work. That can get messy.