My first experience with Vicodin® (a generic form, actually; "Vicodin" is a brand name) was the first time I had had a serious sinus infection since becoming an adult. I had learned the hard way that Tylenol with codiene did not work to ease pain for me and so the doctor prescribed Vicodin.
Always listen to the warnings the pharmacist gives you when you get new medication.
I was given 5/500mg pills (5mg hydrocodone/500mg acetaminophen). The prescription was to take two as necessary not to exceed four times daily. The bottle had warnings that it could cause drowsiness and that if it upsets your stomach to take it with food. The pharmacist knew that it would almost assuredly upset a person's stomach if they hadn't eaten, but the label did not reflect that. I took one. I had not eaten. This was a mistake.
I was a receptionist, which is not a particularly active job. When my equilibrium slid sideways and the world started spinning around me, I knew that it was time to lie down. It didn't stop the world from spinning, but it did keep me from feeling as if I were going to fall off. I think I now have an inkling of what it must be like to suffer agoraphobia. After a short while, the nausea set in. This, on it's own, is bad enough, but trying to empty an already empty stomach is extremely unpleasant.
If you must take Vicodin and you have not eaten within the last hour, then I would suggest having a couple pieces of buttered bread, a handful of crackers or something similar that would hinder the absorbtion of the drug. This is the same way that those wishing to have extended drinking sessions before becoming totally bombed do it. Pasta, bread and high starch foods work best.