Other conditions
Nicotine replacement therapies should be used cautiously in individuals with the following conditions: severe reactive airway diseases (for nasal spray), chronic nasal disorders such as sinusitis, polyps, rhinitis, or allergy (for nasal spray), diabetes (insulin-dependent), gastrointestinal diseases such as esophagitis, active gastric or peptic ulcer disease, liver problems, hyperthyroidism,pheochromocytoma, phenylketonuria (for lozenges), renal problems, and skin conditions such as psoriasis or dermatitis (for the transdermal patch). Mechanism of action
Nicotine replacement therapy works by reducing cravings due to nicotine addiction. Smoking cigarettes releases high doses of nicotine to the brain in a matter of seconds as opposed to low doses released over a period of minutes to hours by the various forms of nicotine replacement therapy. Nicotine from NRT does not reach as high a concentration in the blood as does nicotine from smoke inhalation due to different absorption methods. NRT relies on systemic venous absorption, whereas nicotine from cigarettes reaches the arterial system. Nicotine replacement products vary in the time it takes for the nicotine to enter the body and the total time nicotine stays in the body. The more quickly a dose of nicotine is delivered and absorbed, the higher the addiction risk. It is possible to become dependent on some NRTs.Nicotine patches are applied to the skin and continuously administer a stable dose of nicotine slowly over 16–24 hours. Nicotine gum, nicotine sprays, nicotine toothpicks, nicotine sublingual tablets, and nicotine lozenges administer nicotine orally with quicker nicotine uptake into the body but lasting a shorter amount of time.
A cigarette delivers an average of 1 mg to 3 mg of the nicotine contained in it. NRT products typically aim to parallel this, but the amount of nicotine absorbed by the user is less than the original dose. Nicotine nasal sprays are formulated in doses of lowest strength, available in 0.5 mg and 1 mg strengths. Nicotine lozenges deliver doses as low as 1 mg up to 4 mg. It is not chewed as the gum would be, and dissolves in approximately 30 minutes. This formulation may be preferred by those individuals who do not find gum chewing to be acceptable. Nicotine gum is available in doses of 2 mg and 4 mg. Using 4 mg nicotine gum versus 2 mg gum increases the likelihood of successful smoking cessation. When using the gum, acidic beverages like soda, coffee, or beer should be avoided fifteen minutes prior and during use because they can impede proper absorption of nicotine.Nicotine inhalers come in 10 mg and 15 mg cartridge strengths and typically deliver around 4 mg in one dose. The inhaler may be preferred in individuals who want to satisfy the hand-to-mouth ritual that smoking provides.Transdermal patches deliver between 5 mg and 52.5 mg of nicotine, which results in plasma levels similar to that of heavy smokers. Combining nicotine patch treatment with a faster nicotine-delivery means, like nicotine gum or spray, improves the likelihood of successful treatment.