Mirtazapine is a medication which blocks the 5HT3 receptor in addition to having antidepressant effects, leading to an antiemetic effect. It has successfully been used as an antiemetic drug in patients undergoing chemotherapy and chemotherapy nausea is BAD. You can use it as an antiemetic at low dosages. I have done some research and people use about 15mg of it as an antiemetic but you should test yourself and see which dosage works best for you.
As for Hydrocodone, I only know of tablets with Acetaminophen in addition to Hydrocodone. Are these what your tablets are like? If so, how much of each drug is in each?