The blood test, which is a measure of the rate at which nicotine is metabolized, may eventually be performed non-invasively using saliva or urine samples. "The ultimate aim here is to distinguish smokers who are likely to benefit from a standard dose of nicotine patch from those who may need a higher dose patch or an alternative therapy in order to succeed in quitting," said lead researcher for the study, Caryn Lerman, PhD, Associate Director for Cancer Control and Population Science at the Abramson Cancer Center of the University of Pennsylvania, and Director of the University of Pennsylvania Transdisciplinary Tobacco Use Research Center.
When nicotine is metabolized - or broken down in the body - it turns to cotinine. Cotinine is then metabolized to 3-hydroxycotinine (3-HC) by an enzyme in the liver. This study measured the ratio of these two breakdown products of nicotine among 480 smokers. A high ratio meant rapid metabolism of nicotine, which was associated with higher amounts of craving and greater difficulty in quitting cigarettes using the nicotine patch.
The smokers who participated in the study quit smoking and started using either the patch or the nicotine nasal spray for eight weeks. Measurements of carbon monoxide levels in exhaled air identified those who were not smoking at the eight-week and six-month intervals following the quit date. Study participants also provided information on level of cravings for cigarettes one week after their quit date.
"Using the rate of nicotine metabolism, we were able to predict the level of cravings and the efficacy of the nicotine patch," said Lerman. "Similar results could not be obtained for the nicotine spray, most likely because the subjects were able to compensate for rapid metabolism of nicotine by using the spray more often."
"If a prospective study replicates these results, we will be in a position to recommend this blood test to tailor the type and dose of nicotine replacement therapy for smokers who wish to quit," Lerman said.
This study was funded by the National Cancer Institute, the National Institute on Drug Abuse, and the Pennsylvania State Tobacco Settlement. The Robert Wood Johnson Foundation has also supported the University of Pennsylvania's Transdisciplinary Tobacco Use Research Center, which conducted this research.
The paper based on this study is scheduled for the June issue of the Journal of Clinical Pharmacology and Therapeutics. It has been posted on the web for subscribers.
About the Abramson Cancer Center
The Abramson Cancer Center of the University of Pennsylvania was established in 1973 as a center of excellence in cancer research, patient care, education and outreach. Today, the Abramson Cancer Center ranks as one of the nation's best in cancer care, according to US News and World Report, and is one of the top five in National Cancer Institute (NCI) funding. It is one of only 39 NCI-designated comprehensive cancer centers in the United States. Home to one of the largest clinical and research programs in the world, the Abramson Cancer Center of the University of Pennsylvania has 275 active cancer researchers and 250 Penn physicians involved in cancer prevention, diagnosis and treatment. More information about the Abramson Cancer Center is available at: www.pennhealth.com/cancer
About The Leonard and Madlyn Abramson Family Cancer Research Institute at the Abramson Cancer Center of the University of Pennsylvania
The Abramson Family Cancer Research Institute serves as the forum for integrating cancer research, education, and patient care at the Abramson Cancer Center at the University of Pennsylvania. The Institute supports innovative cancer research, leading-edge care that is delivered in a compassionate manner, and the education of professionals who share a commitment to innovative cancer research. The Institute has set a new national standard for interdisciplinary cancer research and treatment, and is creating knowledge that will offer even greater hope for cancer patients and their loved ones