The Pharmacology of Nicotine

Instructor: Adrianne Baron

Adrianne has taught high school and college biology and has a master's degree in cancer biology.

Nicotine has been a part of our society for thousands of years. In recent history, it has been used to help individuals stop smoking. This lesson is going to cover the pharmacology of nicotine by looking at how it works and its effects on the body.


What is the most addictive drug in the world? You may think cocaine or heroin, but the answer is actually nicotine. Nicotine is a stimulant drug that alters the mind and activates the fight-or-flight response. Many people refer to this as an adrenaline rush. That is one reason why nicotine is so addictive.

Those who quit using nicotine usually have withdrawal symptoms. There are some instances where people quit cold-turkey without a problem, but withdrawal symptoms are one of the main reasons why people relapse and start using nicotine again.

Nicotine patch used for nicotine addiction
Picture of a nicotine patch

One of the best options for getting off of nicotine is to step down from it using a series of lower doses of nicotine. Scientists have developed nicotine gums, patches, and other items to be used from a therapeutic standpoint to decrease withdrawal symptoms. Nicotine may also be given directly into the bloodstream where it causes the release of several hormones that change various functions in the body.

Mechanism of Action

There are two different mechanisms of action that nicotine follows. One creates the adrenaline rush, and the other creates a feel good feeling.

  1. Nicotine binds to receptors on the surface of cells in the adrenal medulla that are responsible for releasing epinephrine, the hormone commonly called adrenaline. Nicotine binding to these cells causes sodium to flood in, which causes calcium to flood out of the cells. The movement of calcium makes the cells also release epinephrine into the bloodstream.
  2. Nicotine binds to receptors on the surface of neurons that are responsible for the release of dopamine. Dopamine is both a hormone and neurotransmitter that controls the areas of the brain where we feel pleasure and rewards as well as seek rewarding actions. Once nicotine binds to the neurons, it causes the movement of sodium, potassium and calcium across the neuron membranes. Calcium movement stimulates the neuron to release dopamine, which acts on cells in the brain to give that relaxed feeling of euphoria.

Effects in the Body

Nicotine makes the brain send signals to relax the body and make it feel rewarded. The same signals also cause a person to want more nicotine to have the same feeling again. So what effect does nicotine have on the body?


The release of epinephrine causes the heart to beat faster, sometimes getting to a fatal point. It also makes blood vessels constrict, which raises the blood pressure. If the blood vessels that provide oxygenated blood to the heart become too narrow, problems can arise. These side effects are the main reasons why using nicotine is not advisable for people that have heart and/or blood vessel diseases and conditions.


Nicotine can alter blood sugar levels due to creating an increase in the amount of insulin in the blood, which would cause a drop in blood sugar. Or it can make a person build up a resistance to insulin, which would raise the blood sugar.

Speaking of blood, nicotine may cause the platelets in the blood to gather in certain areas of the body. This leads to the development of blood clots, yet another life-threatening effect of nicotine.


Using nicotine can also aggravate the symptoms of asthma. This is especially true when the nicotine is inhaled through an inhaler or nasal spray. Spasms in the muscles of the airways can occur, and are made worse in a person with asthma.

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