I'm going to assume you meant to say "Due to my metabolism".
Now, the poison used by James is a substance known as Halon, in a capsule, which is ingested orally. Halon is a gas which bonds with oxygen atoms, and pulls them into itself incredibly well. Once the capsule opens, it will effectively suck all oxygen out of your bloodstream, removing your ability to absorb oxygen. It is rather like carbon-monoxide poisoning, except far more effective. Unless your metabolism allows you to survive without the need for oxygen, Halon will most definitely kill you.
At first, you will feel drowsy. It will not feel like suffocation, because you are still breathing in air. However, after around 3 minutes the brain will shut down, knocking you out. After this has occurred, it will be about 2-3 more minutes before complete brain death. However, 1 minute will be sufficient time for serious and permanent brain damage to occur, which can result in personality change, memory loss, blindness, deafness, loss of speech, loss of bowel control, paralyss in it's many forms, the loss of the ability to make new memories, dementia, and going into a coma.
All in all, it is a relatively slow-working orally ingested poison, which kills through removal of oxygen from the bloodstream.