Vampires are able to eat and drink as humans, it can even sustain them for a while also, but blood is needed for their powers and such to remain active and maintained.
There are two main drugs, or narcotics, in Casa di Falcorvo, Fang and Claw.
Fang is a drug that is mostly vampire blood, giving the user heightened senses, primarily vison, speed, reflexes, and depending on the source, certain vampiric powers.
Claw is derived from Lycan blood. As with Fang it heightens the senses and reflexes. However, rather than making them faster, it makes the user stronger, and the heightened senses are more towards smell and taste.
Both drugs enhance the users hearing also, though neither will allow the user to change form, no matter how powerful the donator of the blood is or was. The human body would not be able to cope with it, they would have to be turned fully to be able to do so.
As it stands, Fang and Claw cannot be combined. The reason is unknown at present, but Fang dominates Claw, so if Claw has been taken and then Fang, or vice versa, Fang will always stop Claw from working. There are rumours however that there is a scientist, or group of, who are trying to find a way to combine them in to a super-narcotic, something new that is Fang and Claw combined. This rumour has been circulating for several years now, but no evidence has been presented to back up the claim, nor is it certain who originally said it.