Nicotine Toxicity

Nicotine is a common stimulant drug found worldwide in many cultures, and is often consumed for it’s stimulatory effects. Nicotine usage has been common throughout different cultures, manifesting itself in the chewing of certain plant material or smoking compounds that contain nicotine. This drug is one of the most commonly used worldwide following alcohol, and presents a clear epidemiological concern in the present day with the rise of alternative nicotine sources besides cigarettes, such as electronic-cigarettes and hookah pipes. Nicotine has potent addictive qualities at continued low doses over time, as it stimulates the “reward center” of the brain. (Robison 2011).

Nicotine predominantly is extracted from the leaves of the Nightshade family of flowering plants, including tobacco, where it naturally exists as an alkaloid byproduct. Nicotine’s mechanism of action  allows for it to work at the same locations within the nervous system that are responsible for controlling muscle movement, and in fact preferentially binds to the sites within the nervous system that are responsible for this behavior. In nature, nicotine is primarily used by plants as a pesticide, as low concentrations are enough to dissuade or kill potential herbivores.

Fig 1, An example of a flowering nicotine-containing plant (Google Images)

Although nicotine in the concentrations found within cigarettes is of little acute danger to the smoker (Armitage 1975), the mechanisms by which nicotine can enter the body are more diverse. Nicotine is capable of being absorbed through the skin and mucous membranes such as the mouth, and it is much easier to have acute effects due to high concentrations of nicotine absorbed in these situations. This is specifically an issue in the case of teething children , who are both more likely to accidentally come into contact with and consume nicotine products, as well as being less resistant to the acute effects due to smaller size. With the LD50 of nicotine found to be between .5 and 1.0 grams nicotine per kilogram of body weight, a curious infant will have a much more intense response to consuming a discarded cigarette than an adult smoke might have from smoking several cigarettes themselves. Alternative accidental sources of nicotine overdoses include all forms of tobacco, with special mention being made of chewing tobacco, pipe tobacco, and specific nicotine delivery systems including liquid nicotine refill capsules for electronic cigarettes and nicotine gum.

Liquid nicotine refill capsules present another threat, as they tend to contain higher concentrations of nicotine then alternate sources, and may be absorbed through skin and mucous membranes easily, leading to accidental poisonings.

Figure 2: Nicotine’s effects on neurons, limiting the uptake of acetylcholine and promoting the production of more acetylcholine as a result. (Google Images)

In years past when the primary commercial form of nicotine was within cigarettes, the cases of accidental ingestion and subsequent acute toxicity were rather low, occurring predominantly with mobile infants of less than 6 years of age eating cigarettes, with teething infants between 6 and 36 months being at greatest risk. With the rise of electronic cigarettes, and the liquid nicotine capsules therein, the chance of accidental contact and acute toxicity increases. CDC notes from the field indicate a rise in percentage of nicotine-toxicity related incidents arising from electronic cigarettes as compared to traditional cigarettes.(Chatham-Stevens 2014) Additionally, while the knowledge of tobacco’s harmful effects is known in the public consciousness, the danger of acute nicotine exposure is significantly less popularly understood. With it’s profound effects on connections within the brain and control of muscles, nicotine can be recognized as less benign then some might think when compared to other drugs.

7 Replies to “Nicotine Toxicity”

  1. I thought that this was a good article because the author set up the background of nicotine before delving into the scientific specifics. Also, for those words that I did not understand, I was able to click on the link and they were explained in greater detail.

  2. I thought this post was very easy to follow, and well-written. As someone who doesn’t have a scientific background, I was easily able to follow what you were saying because it was very well explained. I also appreciated that there were links embedded in the text to follow on words such as “epidemiological” and “mechanism of action,” because reading the definitions helped build some background knowledge and more readily understand the implications of the topic.

  3. Hi Anthony,

    I thought this was a really interesting article, and I think you hit on some nice points. I just had a few general suggestions/questions:

    1) You mention the possibility that acute nicotine toxicity could be on the rise considering the rise of electronic cigarettes. Do you have some sort of citation for this thought? It seems unsubstantiated, and I’d be interested in learning more about the potential for increased risk.
    2) You refer to infants a couple times throughout the article as a particular at-risk population. Can you be more specific about what ages you’re referring to (e.g., I assume there is a greater risk for 2-year-olds, who are more mobile and curious, than newborns)? Are there other populations who are particularly at risk for nicotine toxicity, or is the main at-risk group children who are eating cigarettes?
    3) Are there other causes of nicotine toxicity besides cigarettes?

    Nice article, thanks for the information!

  4. Article was understandable and the science was clear, but the article could use some tighter editing from a grammatical standpoint. Using it’s for its, as one example and “much more” where just more would suffice. Simpler sentence construction would highlight the author’s information more effectively. Also, the closing sentence seems to refute the information in the article itself. Overall, accessible to a non-science audience.

  5. Easy to understand except for the part about alkaloid biproducts. I clicked on the link and that still didn’t help too much in the context of Nicotine. This page needs to be organized a little more clearly in terms of paragraph order and the flow from one sentence into the next, as there was some redundant or repetitive information. Perhaps sub headings could help with the organization of the piece.

  6. Anthony,

    A very interesting article, and a fascinating public health topic. I have several questions which I’d appreciate if you could address.

    You bring up the point that an increased use of e-cigarettes may be related to an increase in acute nicotine toxicity cases. An interesting point from the paper you site is that a majority of e-cigarette poisonings were children aged 0-5 (51.1%) most likely due to spills of the liquid nicotine cartridge. How does this differ from regular cigarettes, where the primary exposure in children was through ingestion?

    Additionally how are e-cigarette producing companies responsible to create a create products which produce consistent amounts of nicotine per puff? As brought up in a recent paper (McRobbie 2014. DOI:10.1111/add.12410) nicotine concentration in e-liquid is not related to nicotine in vapour, with a huge variation of nicotine delivery from 300 puffs ranging from ~2mg to ~15 mg. What is the nature of this new e-cigarette beast for regulatory agencies?

    Cyrus E. Kuschner

    1. Hey Cyrus, thank you for the thought provoking questions!

      The route of subcutaneous absorption is a little trickier than direct ingestion, as depending on factors including blood flow, tissue density,and cellular metabolism, nicotine can be absorbed over a longer period of time and affect more systems in a disparate manner than if it were moving from stimulation gastrointestinally.

      In children, the small body size and rapid metabolism means that a lesser dose of nicotine will have more profound effects upon the body then might otherwise occur, much as how a toxin such as alcohol will affect a 120 lb individual at faster rate than a 300 lb individual.

      In regards to the regulatory question (very neat paper!), I would expect regulatory agencies to act to standardize flow rates of nicotine liquid and vapor in these devices, as from that established rate the variable concentration can be used to better discern the quantity of nicotine over time consumed by the smoker

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