Smoking cessation drug chantix (varenicline) may lead to increased risk of cardiovascular serious adverse events

Smoking cessation drug chantix (varenicline) may lead to increased risk of cardiovascular serious adverse events

Varenicline, a drug launched in 2006 after receiving marketing approval from the US Food and Drug Administration, which is widely used to help smokers to quit smoking, increases the risk of serious cardiovascular adverse events by 72%, states an article in CMAJ (Canadian Medical Association Journal).

The risks of serious cardiovascular illness and death are often motivating reasons for people to quit smoking, and they resort to drugs such as varenicline. Although the US FDA approved the drug for sale, the safety reviewers based on the data submitted to them, had stated that the drug could increase the risk of cardiac adverse events among smokers with any heart disease. Based on this increased risk the FDA has recently updated the product label of Chantix, a brand name for Pfizer's varenicline drug.

The serious effects of varenicline on the cardiovascular system of tobacco users were thoroughly studied by a group of scientists from Johns Hopkins University School of Medicine, Baltimore, Maryland; the University of East Anglia, Norwich, United Kingdom; and Wake Forest Baptist Medical Center, Winston-Salem, North Carolina. Both smokers and smokeless tobacco users were included in the research and serious cardiovascular adverse events of varenicline were compared with those of placebos in 14 previously conducted clinical studies.

Data for a total of 8,216 patients enrolled in two study arms were analyzed. 4,908 patients were enrolled in the varenicline arm and the remaining 3,308 patients in the placebo arm. 13 out of the 14 clinical trials studied in this research included people with a history of heart disease.

The authors in their report have stated that 52 patients (1.06%) in the varenicline arm experienced adverse events compared to only 27 patients (0.82%) enrolled in the placebo arm. It is as well worthwhile to note that seven subjects died in both study arms.

Dr. Singh, from the Johns Hopkins University School of Medicine, Baltimore, Maryland, with coauthors writes:

"Among tobacco users varenicline use was associated with a significantly increased risk of serious adverse cardiovascular events greater than 72%.

However, despite achieving more than twofold higher rates of abstinence in the trials, which should potentially induce a cardiovascular benefit, the participants allocated to varenicline experienced an increase in the risk of serious adverse cardiovascular events."

The researchers further state that smokers either with or without heart disease are at increased risks of cardiovascular adverse events. The issuing of a boxed warning, which is the highest level of warning for any drug, by the US FDA for varenicline, was a result of additional risks of depression, agitation and suicidal thoughts.

Although irregularity in data and insufficient statistical strength were some limitations of the present study, the group of scientists concludes that:

"Clinicians should carefully balance the risk of serious cardiovascular events and other serious neuropsychiatric adverse events associated with varenicline against their known benefits on smoking cessation."

In a commentary related to the present study., Dr. Taylor Hays from the Mayo Clinic writes:

"Although these results suggest a measure of caution should be taken in prescribing varenicline for tobacco dependence treatment, the small absolute risk of cardiovascular events associated with varenicline treatment is outweighed by the enormous benefit for reducing cardiovascular morbidity and mortality that can be achieved with successful smoking abstinence.

(conclusion) The risk for cardiovascular events is low and is far outweighed by the benefits of diminishing the truly "heartbreaking" effects of cigarette smoking."

Link to Abstract of Article

Varenicline and the risk of psychiatric conditions, suicide, crime and RTA (Video Medical And Professional 2020).

Section Issues On Medicine: Other