Heavy smokers are more successful on 4 mg than 2 mg nicotine gum.

Smokers who are heavily dependent on nicotine (scoring 7 or more on the Fagerstrom Test for Nicotine Dependence) may not obtain a sufficiently high level of nicotine replacement from the 2 mg gum and are likely to benefit from a higher dose.

Heavily dependent smokers generally require the highest available nicotine patch dose.

Fiore MC, Bailey WC, Cohen SJ, et al. Treating Tobacco Use and Dependence. A Clinical Practice Guideline. Rockville, MD: US Department of Health and Human Services, 2000. http://www.surgeongeneral.gov/tobacco/treating_tobacco_use.pdf

Silagy C, Mant D, Fowler G, et al. Nicotine replacement therapy for smoking cessation (Cochrane Review). Cochrane Database of Systematic Reviews 2004; 3. http://www.cochrane.org/reviews/en/ab000146.html