Smoking is one of the leading causes of mortality and morbidity. Every year over 19,000 Australians die from smoking-related diseases, representing 82% of all drug-related deaths. Smoking can lead to lung cancer, chronic bronchitis, emphysema, and is also a major risk factor for ischaemic heart disease.
Nicotine Replacement Therapy (NRT) aims to reduce the severity of tobacco withdrawal symptoms and increase the likelihood of smoking cessation.
Compared to a placebo, NRT has been shown to increase the chances of people quitting smoking by 1.5-2 times regardless of additional social support. Many different formulations of NRT exist on the market, such as patches, gums, lozenges, sublingual tablets, inhalers, and sprays. Nicotine replacement via the gastrointestinal tract is generally not suitable for NRT as nicotine is subject to first-pass metabolism.
Also, smokers generally prefer the peak effect achieved when nicotine is absorbed directly from either the oral mucosa or the pulmonary system (as in smoking itself) before crossing the blood brain barrier. Cigarettes usually contain 10mg of nicotine or more, with 1-2mg per cigarette being inhaled by the smoker.
This article seeks to describe and compare various formulations of NRT, and discuss the usage of combination NRT to increase the chances of smoking cessation.
Nicotine gums are available in 2mg and 4mg strengths. When the craving starts, the gum is chewed slowly until there is a bitter or tingling taste. The gum is then parked between the cheek and upper gum until the tingling and taste subside. The cycle is repeated until the craving disappears.
People with high nicotine dependence can initially chew up to 6-10 pieces of 4mg gum daily. The dose is then slowly tapered over two months to the 2mg gum, then stopped or tapered after a further four weeks, until ceased. For people with moderate nicotine dependence, 8-12 pieces of 2mg gum are chewed daily, then the dose is slowly tapered according to a regimen, or at the person’s discretion.
People using nicotine lozenges should allow them to slowly dissolve in the mouth, and avoid chewing or swallowing, as this can reduce the amount of nicotine that is absorbed. Refraining from eating or drinking is also advised during this period.
Those with moderate to high nicotine dependence can start with 4mg lozenges. Those with low to moderate dependence can start with 2mg lozenges.
In both cases, the person should suck one lozenge every 1-2 hours, slowly increasing the amount of time between lozenges during weeks 1 to 24, until they are used only when necessary. Some manufacturers recommend a 12-week program, while Quit® recommends up to nine months.
Seeking medical advice with the intent to completely stop smoking is best, as there is no clear evidence that cutting down, without ever actually quitting, has any health benefits in the long-term.
The method of sublingual tablet usage is similar to lozenges. They are placed under the tongue and will slowly dissolve over half an hour to release nicotine. One or two sublingual tablets can be used every 1-2 hours, or according to cravings, with a maximum of 40 tablets daily. The dose can be gradually tapered over 8-12 weeks.
Nicotine inhalers differ slightly to the other formulations. To use them, the person loads a cartridge and draws on the inhalator mouthpiece when the cravings start, allowing nicotine to be released slowly.
Each cartridge lasts around 40 minutes, and is useful for people who miss the hand-to-mouth movements while smoking. The usual dose is 6-12 inhalation cartridges daily, according to cravings, for 8-12 weeks, and then tapering the dose over subsequent weeks.
Nicotine patches are the only form of NRT subsidised by the Pharmaceutical Benefits Scheme. They come in three different strengths to reflect the number of cigarettes smoked in a day. They work by gradually releasing a basal level of nicotine over a 16 or 24 hour period, allowing it to be absorbed via the skin into the bloodstream.
The 24-hour patch is useful for those who have early morning cravings, while the 16-hour patch is preferred if sleep disturbances occur. If not removed while sleeping, the 16-hour patches will continue to release nicotine from the large reservoir over 24 hours, although plasma levels of nicotine will decline over the last eight hours.
The method of usage involves applying the patch to a clear, hairless part of the body (preferably the upper body or arm), removing it after the specified period of time, and placing a new patch on a different site. Depending on the level of nicotine dependence, a higher dose patch can be applied and then slowly tapered, or stopped abruptly, at about 12 weeks.
Lastly, the Nicorette Quickmist® spray is a new formulation recently released to the market. It works by discharging a spray of nicotine into the mouth, allowing the nicotine to be absorbed via the oral mucosa into the bloodstream. The dosage is 1-2 sprays every half to one hour for the first six weeks, with the number of sprays used daily during weeks 7-9 slowly reduced to half the average of the first six weeks. Treatment is ceased at week 12, or used only when required.
When deciding between NRT formulations, there are a plethora of factors to consider such as the adverse effects. Irritation of the mouth and throat, as well as sinusitis, are associated with usage of gum, lozenges, sublingual tablets and inhalers, whereas skin irritation and allergies may occur with patches.
Contraindications should also be considered. For example; asthmatic patients should avoid using the inhaler. Pregnancy and lactation also plays an important role in influencing NRT choice. In this case short-acting formulations are favoured over patches, as patches tend to release nicotine over a longer period of time, and can pass through the placenta, affecting the baby.
Another significant factor would be the severity of cravings and withdrawal symptoms. For smokers who have acute cravings, the preferred formulations would be the short-acting formulations such as the inhaler, spray, gum, lozenges, and tablets, as patches cannot be used for relief of acute cravings.
Ultimately, the choice of formulation would depend on the person’s preference.
Evidence has suggested that a combination of NRT products can increase the success rate of smoking cessation. As it may be difficult to deliver an adequate dose of nicotine to a highly dependent person using a single formulation, the patch can be used to provide a baseline level of nicotine while supplemented with short-acting formulations for acute cravings.
Editor’s Note: To learn more about Hospital Admission, Abrupt Smoking Cessation, and the Potential for Drug Interaction, read this article.
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