Cigarette smokers metabolize caffeine nonsmokers.

FASTER than nonsmokers

Caffeine are usually metablize by the liver. Cigarettes smoking has an effect on our metabolism. The by products of smoking enhances the activity of liver enzymes. These enzymes are responsible for metabolism of compounds in the body. This is the reason why smokers typically lose the effect of caffeine faster. They metabolize caffeine faster and excrete it as byproduct. Smoker can also be found to drink caffeine more often than non smoker this is also explains that habit.