As for tainted psychoactive drugs, I'd give them the same effect, but add some Nightmare dice too instead of Banality. Why? Well, Wyrm taint isn't exactly the same thing as Banality. It's corrupt entropic energy, with a static bent. Banality is more static than entropic. Entropy is, arguably, still Glamorous, albeit in a darker way. So I think Wyrm taint is best represented with Nightmare dice instead.
Now, for drugs in general, I'd use the rules in V20 and just consider whether it contributes to Bedlam (probably). But Nightmare dice are a good way to simulate Wyrm taint.