Nicotine gum: The pioneer of nicotine replacement products contained nicotine resin in gum which allowed smokers to absorb about 50% of nicotine levels produced by smoking. It is easy to buy over the counter (OTC) without a prescription, and was also convenient and easily titrated. The problem with gum was the oral and gastric side effect (Henningfield 1990) that could occur due to over-zealous continuous chewing. Nicotine absorption was reduced when a smoker drank coffee or soft drink, an event which was common (Hughes 1986). An alternative to gum are lozenges which is slightly more expensive but removes the need for chewing.

Skin / Transdermal patches: These is a stick on skin patch over 24 hours that delivers the same baseline nicotine level of heavy smokers. This is the easiest to use and people who use patches for 2 weeks before attempting to quit smoking were slightly more likely to succeed! (Schuurmans 2004). However, when compared to Zyban, one large study (Jorenby 1999) showed that Zyban is more effective than nicotine patch, and that if you are on Zyban, then there is no benefit of adding another NRT, although it cannot hurt your chances to stop smoking. A good example of a nicotine patch is Nicabate CQ.

Nasal sprays: The nicotine spray delivers nicotine to the nasal mucosa and results in a more rapid absorption compared to patches or oral NRP. The rise in blood nicotine level is similar to that seen in cigarette smoking (Hughes 1999). Nasal irritation is the most common complaint and in 81% of people, it persists up to 3 weeks of use. In conclusion, it is very effective but also has the highest side effects among the NRPs.

Nicotine inhalers: This has been the most successful NRT product in helping people stop smoking (Silagy 2007) although data supporting this is still small. It closely mimics the mechanics of cigarette smoking and addresses a smoker’s need for finger manipulation. The mist from the inhalers are heavier and larger than smoke and stick to the mouth and throat before reaching the lung.

Mecamylamine: There is now another new drug that blockes (antagonises) nicotine receptors and is currently being tested to see its effectiveness is stopping smoking addiction and maybe improving the success of nicotine replacements. More to come later

Conclusions:
Below are the conclusions provided by a thorough review of nicotine replacement products performed by Silagy at the Cochrane library in 2007. Silagy died in 2001 but his work continues:

1. All NRT are effective in promoting smoking cessation by 1.5 to 2 fold regardless of setting. NRT is only beneficial in motivated cigarette smokers who want to stop and who smoke more than 10 to15 cigarettes a day. There is no benefit if you smoke less.
2. Patches are the easiest to use and smokers can benefit from combining patches with gum or inhalers. (Silagy 2007)
3. 8 weeks of patch therapy is as effective as longer courses and there is no need to taper off patches. Wearing patches for 16 hours when you are awake is as effective as using it 24 hours.
4. The effectiveness of NRT is does NOT depend on additional support provided to the smoker, even though it is recommended. Will power and motivation are the most important factors.
5. NRT does not increase risk of heart problems in smokers with heart conditions (please check with your regular doctor)
6. Nicotine patch was less effective than bupropion in one trial.