NO start at the beginning therapeutic dose of 5mg and wait at least an hour before dosing again. As well do not mix it with another type of sedating drug. Taking 15 of hydro with diph could easily be to much for a non tolerant individual.
15mg of Hydrocodone is fine for a first time user. 20mg was my first dose and I was fine and I'm quite a lightweight.
Obviously i would like to start this off by saying that this mentality of using this drug for recreational use is a bad road to go down, but i have done it as well, so this is slightly hypocritical, but either way, please be very careful when using these drugs. Space out your usages.
Either way, start at 15mg with some diphenhydramine, youll be feeling great.