Several drug treatments are already available in the market today to help smokers quit and another class of medications has the potential to join the list, according to researchers from the University of Pennsylvania.
For a study published in the journal Translational Psychiatry, Rebecca Ashare and colleagues carried out rat and human trials to examine the effects of the acetylcholinesterase inhibitors (AChEIs) donepezil and galantamine on overall nicotine consumption. AChEIs are approved by the FDA to improve cognitive impairments arising from Alzheimer's disease.
The researchers reported a drop in nicotine intake in rodents pretreated with AChEI, a result consistent with findings from the human trial, which had participants taking an AChEI smoking 2.3 fewer cigarettes in a day and feeling less satisfied when they did smoke.
Research on smoking cessation has been ongoing since 2001 at Penn's Center for Interdisciplinary Research on Nicotine Addiction. Ashare and her fellow researchers turned to AChEIs because results from years-long research showed that those who quit smoking experienced a decrease in executive functions.
Acetylcholine is a neurotransmitter important for cognitive functions like short-term memory and learning. When nicotine is consumed, it binds to the same brain receptors that acetylcholine targets, resulting in the reinforcement and rewarding effects of smoking. By increasing levels of acetylcholine in the brain, AChEIs act as substitutes for nicotine's feel-good effect.
In the human clinical trial, participants were signed on for 23 days, the first two weeks of which they were allowed to continue smoking while taking either a placebo or galantamine. Afterwards, the participants were tasked with not smoking for one whole day. Assessments were done after the two-week cigarette-drug arrangement and after the smoke-free day. For the final leg of the experiment, the participants were told not to smoke for seven days while taking either placebo or AChEI.
"The ability to quit smoking the first week after you make a quit attempt is highly predictive of long-term success," said Ashare.
Participants are still actively being recruited for the clinical trial but so far the researchers have observed that those who are able to resist smoking within their first week being part of the study were 32 times likelier to quit smoking entirely.
The researchers are not looking to replace medications currently approved to aid smoking cessation. Instead, they are hoping to target a different group of smokers: those who have higher chances of experiencing cognitive deficits if they try to quit smoking.
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