Clinical Drug Experience Knowledgebase

Evaluation of Nicotine Receptor Up-regulation Activity Through Metabolic Induction and Changes in Responsiveness Using Surrogate Evaluation Methods

Studies have shown that prolonged exposure to nicotine reinforces addiction. The act of smoking delivers nicotine through lungs into the blood stream. As a result, during smoking nicotine levels peak and then when smoking stops levels progressively diminish to a base (trough) level. At the peak level a smoker feels rewarded, but at the trough level a smoker starts to experience negative withdrawal affects and a desire to smoke. Nicotine Gum and Inhalers mimic this smoking behaviour maintaining a peak and trough regime, but nicotine patches do not. Instead, nicotine patches deliver a constant base dose considered to be either above that of the smokers trough level or at a level where negative withdrawal effects are reduced.

The question arises as to if nicotine levels delivered by a patch are constant and potentially above that of the baseline smokers level, does this reinforce the addiction and therefore contribute to the high long term relapse rate? To answer this question the investigators will be looking at metabolites which the body uses to breakdown nicotine and several other enzymes. These metabolites respond to the levels of nicotine in the blood stream by increasing or decreasing over time. By testing blood flow, blood and urine the investigators are able to gain an insight into how the body is dealing with a constant stable dose of nicotine rather than a peak and trough dose. In combination with the questionnaires the investigators will be able to determine the level of affect.