Why I never thought of writing these rules for Blood & Treasure, I don't know, but they would work for that game and most other old school games I should suppose. Obviously, the rules are kept simple and abstract - they're meant to take up a column of the rulebook, not a chapter - but I think they'll do the job.
Strong men often crave strong drink to dull the pain of living, or to celebrate a hard-fought victory. Of course, alcohol isn’t the only intoxicant a man or his enemies might use. Intoxicants are treated as poisons, and thus require a Fortitude saving throw to resist. They come in three broad varieties: Depressants, stimulants and hallucinogenics.
Intoxicants are also given two levels of efficacy – mild and strong. A strong substance not only has a greater effect than a mild one, and it imposes a -10 penalty to save against it.
The dosage of intoxicants varies widely, so use your best judgment. Mild intoxicants have a duration of 1d6 turns, while strong intoxicants have a duration of 1d6 hours.
If a character already under the effects of a mild intoxicant takes another dose and fails his saving throw, treat him as though he has taken a strong intoxicant.
Each time a character falls prey to the effects of a mild intoxicant, there is a 5% chance they will develop an addiction to that intoxicant (rules for that to follow). Strong intoxicants have a 10% chance per use of causing addiction.
MILD DRUG EFFECT
Depressant: -2 penalty to sensory task checks and balance and tumbling task checks, -2 penalty to AC and to all attack rolls, 10% chance per hour of falling asleep
Stimulant: -2 penalty to all wisdom=based task checks and Will saves and saves vs. sleep effects, +2 bonus to all other saving throws and to attack, -2 penalty to AC
Hallucinogenic: Confusion (there would be a page reference here in the rulebook, but if you've played ye old fantasy rpg, you know what confusion does)
STRONG DRUG EFFECT
Depressant: -4 penalty to sensory task checks and balance and tumbling task checks, -4 penalty to AC and to all attack rolls, 10% chance per turn of exhaustion of falling asleep
Stimulant: -4 penalty to all wisdom-based task checks and Will saves and saves vs. sleep effects, +4 bonus to all other saving throws and to attack, -4 penalty to AC, suffers 1d6 points of damage to body per hour of duration, after duration the character is left fatigued for equal duration
Hallucinogenic: Confusion, with a 10% chance that the condition is permanent
Some common intoxicants include the following:
Alcohol: Mild or strong depressantAmphetamine: Strong stimulant
Caffeine: Mild stimulant
Cannabis: Mild depressant and Hallucinogenic
Cocaine: Strong stimulant
Heroine: Strong depressant
LSD: Strong hallucinogenic
Mescaline: Strong hallucinogenic
Morphine: Strong depressant
Mushrooms: Mild or strong hallucinogenic
Nicotine: Mild stimulant
Nitrous: Oxide Mild hallucinogenic
Opium: Strong depressant