Alcohol is treated as a specialized poison. Ales and wines usually have a fortitude save DC of 10-15, most human spirits a 15-20 dwarven or special spirits would have a 21+. Like most poisons, continued “doses” increase the DC of checks that must be made to stave off drunkenness.
Upon entering Stage II, the character must immediately make a second Fort save at the DC of the beverage that caused them to enter this stage. Failure indicates taking 1d8 subdual damage. While in Stage II, the character takes a -2 temporary morale penalty to all mental stats, but keeps the benefits from Stage I. The Stage II penalties have a separate 1d4 hour window from the Stage I bonuses.
After a failed fort save while continuing to drink while in Stage II, the following occurs –
Character loses all benefits from Stage I
Character takes an additional -2 penalty on ALL stats for 1d4 hours. These negatives are innate, and stack with the penalties from Stage II.
Character must make a secondary Fortitude save at the adjusted DC of the imbibed liquid, or lose consciousness or “black out” for 2d4 hours.
If a character reaches Stage II or III of inebriation, they must make a Fortitude save at a DC of what they were drinking (if mixing drinks, they take the highest DC and add 2 for each additional alcohol source) or become hungover when the benefits/penalties of their inebriation state wear off.
Hungover characters are treated as Fatigued, but undertaking any activity which requires a check which is affected by statistics (attacks, skills, some spells) cause them to become exhausted. The duration of a hangover is 1d4 hours for each hour spent Inebriated.
DM may rule that repeated exposure to high levels of drunkenness, or extended periods of hung-over exhaustion may have longer-term detrimental effects on a character (subdual damage or stat penalties which require abstinence and rest to go away).
Any time a drinker fails a fortitude save which would progress them to inebriation, they can opt to vomit, in lieu of progressing. This reduces a drinker one stage of inebriation, but penalties to fort saves for continued exposures continue to last until the character has had a full rest, instead of the normal 1d4 hours. If a character vomits more than once in a drinking bout, they immediately become Fatigued, and they will have a hangover which lasts a minimum 8 hours, even if they are only at Stage I. Monks and Druids are still affected by alcohol, regardless of class abilities, but Dwarves +2 racial bonus against poison also carries over to alcohol. Most creatures with an immunity to poison will have a bolstered resistance to inebriation, like dwarves.