addiction, poison
酖 centers on a harmful substance that takes hold of a person: poison and the resulting addiction. The two meanings are connected by the idea of something toxic that entraps.
酖 combines 酉 (alcohol vessel, often related to fermentation or intoxication) with 冘, which likely contributes the sound and may suggest a sense of sinking or being overcome. The character expresses poison or addictive intoxication.
The alcohol radical 酉 on the left and the sinking shape 冘 on the right suggest a person drowning in drink: poison or addiction that pulls you under.
For タン, imagine a tan-colored poison bottle labeled with the kanji 酖: tan -> タン, and the bottle holds the addictive toxin.