Study: How Genetic Markers May Impact Side Effects from Nicotine Replacement Therapy 

Nicotine patch
A patient’s genetics can impact side effects of nicotine-replacement therapy.

The University of Wisconsin Transdisciplinary Tobacco Use Research Center (TTURC) recently published a study in Nicotine and Tobacco Research suggesting that, while taking nicotine replacement therapy (NRT), specific genetic markers can cause more severe adverse effects for some patients. Dr. Megan Piper, Associate Director of Research at UW-CTRI, and Dr. Tim Baker, Director of Research at UW-CTRI, were co-authors on the paper and played an integral role in the study alongside lead author Dr. Robert Culverhouse and Dr. Li Shiun Chen, Dr. Nancy Saccone, Dr. Yinjiao Ma, and Dr. Laura Bierut from Washington University in St. Louis.

Although NRT has been proven effective for those who have actually taken the medicine as directed, doctors have come to question why some patients don’t adhere to the directions, and neglect to take the medication.

Piper, Baker, and Culverhouse were curious if side effects explained why people weren’t using their medication as directed. As it turns out, it’s a bit more complicated than just a simple, “Yes.”

This study points toward the idea of different smoking cessation medication for different patients, as some may experience adverse effects from NRT on a greater scale than others. While NRT can come with some mild gastro-intestinal (GI) side effects, there is belief that certain genetic markers on chromosome 15 can increase those side effects—causing major GI distress and discomfort to people with the high-risk genes. Interestingly, smokers who experienced greater NRT side effects normally continued using the medication, even though they were more uncomfortable.

The results of the TTURC study point towards a similar result of a 2012 study done by King et al, which used different medication (varenicline and bupropion). In both studies, the adverse effects of NRT showed no effect on successful cessation.

It is believed that the catalyst to this negligence can be found in chromosome 15. Chromosome 15 is home to the CHRNA5-CHRNA3-CHRNB4 region, a part in human DNA connected with nicotine processing and nicotine metabolism.

The study used multiple nicotine replacement products including a nicotine patch, a lozenge, a combination of both the patch and lozenge, a combination of NRT and bupropion and placebo medications as well. Out of all participants in the study, 31.6 percent of people reported adverse GI effects. Although this is a minority in the group, minimizing patient discomfort tends to maximize patient cessation success.

Understanding how these medications affect those who take it can, in the future, create easier and more successful cessation experiences for patients.