Yes. One of the things I learned is that many of the symptoms of nicotine overdose are similar to nicotine withdrawal. One exception seems to be nausea... usually that is overdose as I recall. Most smokers have the experience of being out on the town or whatever, smoking up a storm, and then at a certain point they feel a twinge of nausea and they do NOT want a cigarette for at least an hour or two, in fact don't even want to look at one. This is classic overdose of nicotine. Maybe it manifests differently for some people, but I think most smokers have had this or a similar experience.
The physician with whom I worked would tell stories about patients calling him after-hours, thinking they were overdosing on nicotine... lots of anxiety, maybe palpitations, and so forth. After talking to them, usually he would decide it was was withdrawal and would tell them to use their nicotine nasal spray, which would alleviate the symptoms in about a minute. Often its underdose/withdrawal vs. overdose. Particularly when the person's in stressful situations; this actually increases the amount if nicotine the brain wants/needs.
As I recall, I only ever thought I was getting a bit on the high side of nicotine when using the 4 mg lozenges. For whatever reason, they seem to deliver in a bigger hit than gum, even at the same 4mg strength. I suppose the gum probably releases more slowly, even if you chew aggressively.
Studies in smokers show that they regulate their nicotine levels very tightly, automatically. When they switch people from full-strength cigarettes to lights or ultra-lights, research has shown that the users still get exactly the same amount of nicotine in their blood, again, within that person's very narrow range. The way they do this is that they unconsciously hit more often, hold it longer, and draw it deeper. It is for this reason that it is believed that switching to light cigarettes is actually bad for you (relatively), because smokers expose themselves to MORE of the bad stuff in cigarettes in order to get their required dose of nicotine. I will admit that I smoked lights, but I believe this research that it would be better to smoke fewer full strength cigarettes, all else being equal.
Normal OTC aspirin causes hundreds of deaths per year. It's easy to find this statistic. And yet I'm having trouble finding how many people die from nicotine poisoning a year (not smoking, but nicotine). I'd bet it's probably lower, but would love to see some data. And Tylenol apparently hospitalizes 26K/year and kills ~500/year. (A cousin of mine has a replacement liver courtesy of Tylenol toxicity; her drinking days are long gone, at the ripe old age of 22). In my opinion, nicotine by itself is really not much more dangerous than these two so-called "safe" OTC drugs, and it might actually be safer.
