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Nicotine replacement


Nicotine given as gum, patches, intranasal spray or inhaler is the most widely used method for helping people stop smoking. Does it work, and how good is it? A new Cochrane review [1] has pulled together the evidence.

Searching

Searching was exhaustive. Randomised trials were sought in which nicotine replacement was compared with placebo or no treatment, or studies with different doses of nicotine. Studies had to report cessation rate.

Outcomes

The outcome was smoking cessation, with at least six months of follow-up. The estimate at 12 months was taken when available, with six months being taken only when 12-month data were unavailable. The strictest criterion available was used to define abstinence, preference being given to biochemical confirmation of abstinence. Patients lost to follow up were regarded as being continuing smokers.

Results

The overall results for the main methods of nicotine delivery (gum, patch spray and inhaler) are shown in the Table. The overall NNT for all methods of delivery was 14 (95% CI 13 to 16). There was not much difference between different methods of delivery.
Treatment Number in comparison Percent stopping with control Percent stopping with nicotine NNT (95%CI)
         
Chewing gum 16518 12 19 13 (11 to 15)
Patch 8283 9 15 16 (13 to 21)
Intranasal spray 887 12 24 8.3 (5.9 to 14)
Inhaler 976 9 17 12 (8.1 to 26)

Nicotine gum

There were 47 comparisons of nicotine gum (7248 individuals) versus non-nicotine controls (9270), and in 12 of these gum was better than control. The results are shown in the L'Abbé plot. The NNT was 13 (95% CI 11 to 15).

Nicotine patch

There were 23 comparisons of nicotine patch (4511 individuals) versus non-nicotine controls (3772), and in 10 of these patch was better than control. The results are shown in the L'Abbé plot. The NNT was 16 (95% CI 13 to 21).

Intranasal spray

There were 4 comparisons of intranasal nicotine spray (448 individuals) versus non-nicotine controls (439), and in three of these spray was better than control. The results are shown in the L'Abbé plot. The NNT was 8.3 (95% CI 5.9 to 14).

Nicotine inhaler

There were 4 comparisons of nicotine inhaler (490 individuals) versus non-nicotine controls (486), and in 2 of these inhaler was better than control. The results are shown in the L'Abbé plot above. The NNT was 12 (95% CI 8.1 to 26).

Other conclusions

The report did a number of sub-group analyses to look for situations in which nicotine replacement may or may not be particularly useful. The conclusions were:
  • Eight weeks of therapy is as effective as longer courses.
  • Wearing patches during waking hours (16 hours) is as effective as 24 hours.
  • Gum can be offered on a fixed dose or ad lib basis.
  • For highly dependent smokers who fail with 2 mg gum, 4 mg gum should be offered.
  • Effectiveness of nicotine therapy is independent of additional support intensity
  • Nicotine therapy does not lead to increased risk of adverse cardiovascular events.

Catching them young

While we're on tobacco and smoking, two recent papers in JAMA have examined whether and how tobacco advertising can influence teenagers into becoming smokers.

The first of these [2] found a strong association in adolescents between their receptiveness to tobacco advertising and progression to experimenting with, or actually, smoking. The incidence rate of experimentation over three years to children receptive to tobacco advertising was 34%, but in those who were minimally receptive it was only 22%. The percentage of experimentation in adolescents attributable to tobacco advertising was given as 34%.

And by a quirk of fate, tobacco advertising in US magazines of those cigarette brands popular with young adolescents are much more likely to be found in magazines with high youth readership [2]. As the percentage of youth readership of magazines went up, the proportion of youth-favoured brands went up and adult-favoured brands went down. Strange that.

Reference:

  1. C Silagy, D Mant, G Fowler, T Lancaster. Nicotine therapy for smoking cessation. Cochrane Library 1998 Issue 2 (date of latest amendment 27/5/98).
  2. JP Pierce, WS Choi, EA Gilpin et al. Tobacco industry promotion of cigarettes and adolescent smoking. JAMA 1998 279:511-5.
  3. C King, M Siegel, C Celebucki, GN Connolly. Adolescent exposure to cigarette advertising in magazines. JAMA 1998 279: 516-20.



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