** This is based of the 'poisoning' dosage - there is risk of death at lower dosages, but the most common effect is a 5-hour coma, death resulting from choking on vomit or other such things (as with alcohol).
***I'm not really sure where this came from, actually o.o There's a chance that it's right for nicotine, but I'm not sure. The problem with TIs for tobacco is the method of ingestion (1 cigarette is a normal dose, and the only dose there is, really) as well as the excedingly long (1,000+) ingredient list for a standard cigarette. Not to mention that's not the only method of ingestion.
Sources: Erowid.org, Dale Pendell - <em>Pharmako/poeia</em> and <em>Pharmako/dynamis</em>