Know your drugs: smoke cessation drug varenicline causes psychosis, arrhythmia

Last May 21, the US Federal Aviation Administration (FAA), the government agency that is in charge of civil aviation safety issued a ban on the use of the smoking cessation drug varenicline by airline pilots and air traffic controllers, as reported by the New York Times.

The following day, on May 22, the US Federal Motor Carrier Safety Administration, the agency in charge of safety in the interstate trucking and bus industry also issued the ban for bus and truck drivers.

According to an FAA spokesman, about 150 pilots and 30 air-traffic controllers were on varenicline with permission from FAA but they have been told on May 21 to discontinue taking the drug and to stay away from work for 72 hours until the effects of the drug have subsided.

Earlier this year, the FDA issued a warning against varenicline due to undesirable side effects, which includes

• suicidal acts, thoughts, or behaviours
• hostility or aggression
• accidents and injuries from falls
• heart-rhythm disturbances and heart attack
• seizures and muscle spasms/movements
• skin reactions
• diabetes

Varenicline, marketed as Chantix in the US by Pfizer, comes in the form of pills. Several clinical studies have shown that the drug help smokers quit. It works by partly blocking and partly stimulating a nicotine receptor in the brain. Chantix was approved for market in the US and the European Union in 2006. It is estimated that 6.5 million people have used or are using it, translating to $883 million in sales last year.

The first publicized undesirable side effects of varenicline were reported last year when “a Dallas musician, Jeffrey Carter Albrecht, was shot to death after he began behaving bizarrely while taking Chantix.” Since then, several cases of suicides and psychotic behaviour have been associated with the use of varenicline.

A study conducted by the Institute for Safe Medication Practices (ISMP) reported many of the adverse events listed above. Aside from the psychological disturbances, it seems that varenicline is also potentially proarrhythmic, that is, it causes irregularity in heart rhythms which can be potentially lethal and can lead to heart attacks. People with heart conditions are therefore advised against the use of varenicline.

Aside from pilots and drivers, ISMP also recommends that persons operating highly sensitive machinery and devices such as nuclear power reactors, high-rise construction cranes or life-sustaining medical devices should also be banned from using varenicline.

Smoking causes deaths mainly by causing cancer and cardiovascular disorders. The use of smoking-cessation drugs has become popular in recent years as more and more people are realizing the health benefits of quitting. It is most unfortunate that varenicline, which seems to help people quit smoking, may actually bring more harm than benefit to its users.

However, other options are such as nicotine replacement remedies in the form of patches and gums are available.

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