I'm a materialist myself, but I can think of one very fun theory that solves this. What if neurons are special antennas that can "connect" to your consciousness, and when you're, say, drunk, those antennas start receiving and transmitting wrong signals. Your consciousness is just fine in its world, but your body can't talk to it properly anymore.
Obviously I'm just making stuff up, and I don't actually believe any of this.
In that scenario, I don’t see why your body containing alcohol would change your conscious experience. Surely that would be like being fully alert and aware, but not able to fully control your body. If your body were in its own world, then there would be no reason for drunkenness to affect your awareness or decision making.
Obviously I'm just making stuff up, and I don't actually believe any of this.