Yes.
Isn’t pretty much anything a poison in high enough quantities?
Even without the ridiculous alcohol restriction (sugar is also thought of as a poison by some, as well as meat, for instance,) I would think twice about it before probably accepting. The reason I’d think twice is the possibility of forced imprisonment and experimentation.
And pretty much nothing will be able to effect you physically. How you are when/if you accept the deal is how you stay for 100 years.
So, no new synapses or neurons get created? I won’t be able to remember anything or learn anything new?
Or you could take the offer in the spirit it is given and not try to find shortcuts, cheats, and/or other ways to nitpick it to death.
Hey, you took away beer! Let me have that, and I concede to the spirit of the offer 
I gave you the ability to eat all you want, and the ability to drink everyone under the table. You can try foods you’ve never had before, and sample scotches of dozens of different varieties and remember which ones were good and which were liquid shit. You can enjoy an Anchorage A Deal With The Devil Barleywine (Double Oaked)(ABV 17%) and a cask-strength Kilchoman whisky in the same meal. It’s quite a deal when you think about it.
Can I get high from pot?
You can’t even get high from hyperventilating.
Are you kidding? I’ve been waiting in line all this time. No way am I missing my turn to get off this planet.
So then the maintenance meds I take aren’t effective anymore? I’ll have to change my answer.
Whatever state you are in right now, whether it is due to currently working meds or not, is the state you will stay in-no better, and no worse.
But no ability to forget about my myriad problems and issues for a short while with liquid forgetfulness? Hmmmm…I’ll have to think about it.
It’s not possible to drown, right? And water pressure wouldn’t kill me either?
The contract is for 100 years, and you can’t back out.
I’d do it. I might say no to eternal life under those conditions but a hundred years seems like a reasonable amount of extra life for me. I’m not in great shape but I’d be willing to continue in my present shape in exchange for a hundred extra years of life.
Oh hell no. Why would I want 100 more years in this 49 year old body?
100 more in my 21 year old body? Hell yes.
If I lift weights, do I get bigger/stronger? Conversely, if I stop do I get smaller / weaker?
No way. Absolutely not. To me, that’s more of a nightmare.
No and no.