"The quit smoking pill"
Varenicline, marketed as Chantix in the USA and Champix elsewhere in the world, is a relatively new stop smoking pill marketed by Pfizer, as a prescription medication used to aid smoking cessation. Varenicline works by reducing nicotine cravings as well as the pleasurable effects of nicotine, thus reducing the patient's desire to use tobacco, rather than being a nicotine replacement therapy like the patch or gum. It is an oral medication with FDA approval for use in smoking cessation, used for three months, and prescribed for an additional three months if the program is initially successful.
Effectiveness in quitting smoking
Varenicline is currently the most effective stop smoking pill available, prescription or otherwise, demonstrating a superior effectiveness when compared to Zyban (bupropion), and approximately double the quit rate of placebo groups or unaided quitting attempts. Its quit rate is among the highest of any method, though its effectiveness is matched by certain multiple-format quit methods, such as use of the nicotine patch combined with nicotine gum (read a comparison of the best ways to quit smoking).
Success rates of varenicline after:
3 months: 44%
6 months: 33%
12 months: 23%
These results are among the highest of any method of treatment, and compare favorably to the quit rates of other prescription drugs or unaided treatment.
Comparison of quit rates after a one year period:
Zyban (Bupropion): 15%
Side effects and controversy
Varenicline is only available as a prescription drug, and has carried the FDA's strongest warning due to its involvement in cases involving psychiatric side effects. Though the data is not entirely conclusive, patients and doctors must use caution when administering the drug.
Common side effects include nausea, and less commonly headache, insomnia, and abnormal dreams. Some patients report changes in taste, vomiting, abdominal pain, flatulence and constipation.
The FDA announced more serious side effects found in certain patients, including suicidal or otherwise erratic behavior, saying it is "increasingly likely" that varenicline was connected with more serious psychiatric problems, though without conclusive evidence that it was distinct from normal withdrawal symptoms. The Institute for Safe Medication Practices found varenicline involved with more reports of serious side effects than any other drug, including the above symptoms as well as hostility or aggression, skin reactions, vision problems, seizures, muscle spasms, heart disturbances, and others, though the report itself did not definitely prove varenicline's involvement as the cause of the symptoms. However, other reports showed patients were not necessarily at higher risk than patients not taking the drug, but patients should still exercise caution when considering taking varenicline.
Can I quit smoking with varenicline?
The reports show varenicline to be highly effective as an aid to quit smoking cigarettes, but its potential high-risk side effects indicate that its use should be carefully monitored for serious complications.
Compared to other methods to quit smoking, varenicline has a relatively high success rate, but is not necessarily the most effective way to quit smoking cigarettes, with a success rate comparable to certain multiple-method applications of quit smoking products. See a comparison of effectiveness rates for stop smoking aids.