Nicotine concentrations with concurrent use of cigarettes and nicotine replacement: a review.

This paper reviews the data on blood nicotine or saliva cotinine concentrations with concomitant smoking and use of nicotine replacement (NR) products. Eleven studies that provided data on blood nicotine concentrations, carbon monoxide in exhaled air, and number of cigarettes smoked were reviewed. At least one day had to be spent on concurrent use of cigarette and NR products. With simultaneous use of smoking and acute NR products (gum and inhaler) the nicotine concentrations were unchanged, whereas they increased (+54%) with nicotine patches. With both types of NR products, the number of cigarettes smoked per day was reduced by approximately 50% and carbon monoxide (CO) by 30%. Where smokers had the intention or received instructions to reduce smoking, a greater reduction in cigarettes smoked and exhaled CO was observed. Despite substantially increased nicotine concentrations (e.g., up to 3 times the approved dose) there were no significant adverse reactions. Concurrent use of NR products and cigarette smoking appears to be safe.