Hi there!

Sorry if this is a question which is covered in the rulebook or a known thread - I just couldn't find anything!
I'm trying to get a RAW / RAI / Reasonably plausible guess as to the mechanics of taking more than one drug or more than one dose at a time in SR4.
Do the bonuses / detriments stack? Do only the highest apply? Do multiple doses of the drug have a cumulative effect?
( For example, if the crazed dwarf berserker one of my players runs decides to take three doses of Kamikaze, does he experience pretty much the same effects as a dose of K-10?)

Appreciate any and all viewpoints / answers!

Kludgejob.

AFAIK it's totally up to the GM.

Agreed, nothing in the rules that I've ever seen says specifically, so it is up to your GM.

That said, way I generally figure things work out is that bonuses from different drugs stack (except IPs, since these generally never stack from multiple sources), but taking the same drug multiple times doesn't stack, instead it just increases the duration. I mean, K-10 wouldn't be that impressive if you could get the same effect by just taking two doses of Kamikaze.

I've always played that you're already getting maximum benefit from a single dose, and that is why that dose is the size it is. Anything over that dose, is, well, an overdose, but, instead of making the char go to a hospital and drink activated charcoal or whatever, I just stack the penalties and not the bonuses. I allow mixing of drugs which are fundamentally dissimilar, but two types of tweak aren't going to help a dude. They'll just break the guy.

I think Arsenal has a rule about mixing drugs upping the addiction threshold, but some combos (Psyche/Red mescaline for example) are exempt.