Alcohol - once you drink it, it enters your bloodstream roughly in about an hour's time and begins to get processed. It doesn't sit around in your stomach for a long period of time.

The use of IV replacement of electrolytes and fluids should be in a time when someone is unable to keep fluids down. If your hangover is so bad that every time you drink a sip of Gatorade, you instantly vomit, and you're actively being dehydrated, absolutely you need replacement via an IV.

Maintaining your hydration status is probably the most important thing, along with rest, that you can do with a hangover.

Mikhail Varshavski Quotes