S-Adenosyl-L-Methionine (SAMe) for Smoking Abstinence
Status:
Completed
Trial end date:
2010-06-01
Target enrollment:
Participant gender:
Summary
Cigarette smoking is of great public health importance and is the single most important
preventable cause of morbidity, mortality and excess health care costs in the United States.
After a steady decline for the last 50 years, the prevalence of tobacco use in the United
States has reached a plateau of approximately 21%. Currently available treatments among
adults are not efficacious for all tobacco users. New pharmacologic agents thus need to be
continually developed and tested.
The release of dopamine in the nucleus accumbens is one of the key components of the
pleasurable and rewarding effects of nicotine. Drugs that increase monoamine neurotransmitter
availability (particularly dopamine and norepinephrine) are likely to increase the reward
function and thus ameliorate withdrawal symptoms. S-Adenosyl-L-Methionine (SAMe), the primary
methyl donor for the central nervous system (CNS), donates methyl groups towards presynaptic
synthesis of CNS monoamine neurotransmitters. By facilitating the synthesis of dopamine and
norepinephrine in the brain, SAMe is likely to ameliorate the symptoms of nicotine
withdrawal, thus improving tobacco abstinence rates in smokers who are trying to stop
smoking. SAMe is well tolerated and is available over-the-counter.
To date, no prospective clinical trial evaluating the efficacy of SAMe for the treatment of
tobacco dependence has been published. We propose to evaluate the efficacy of SAMe for
increasing smoking abstinence and decreasing nicotine withdrawal symptoms in a randomized,
blinded, placebo-controlled, three-arm, parallel-group, dose-ranging phase II clinical trial.
Participants (N=120) will be randomly assigned to one of the three groups, and will receive
an 8-week course of SAMe 800-mg per day, 1600-mg per day, or a matching placebo. This study
is anticipated to provide the data needed to develop a larger randomized controlled clinical
trial submitted through the R01 funding mechanism, if the results appear promising.