Chantix is the brand name for the drug varenicline, which is marketed by Pfizer. Chantix is a prescription drug with no nicotine and is prescribed for people who are trying to quit smoking cigarettes, which have the addictive drug nicotine. Chantix is taken in pill form and is not approved for patients under the age of 18. Chantix is designed to help reduce the urge in patients to smoke. Because of the relationship between smoking and weight gain, it is useful to know the facts about Chantix and the side effects of weight gain.
Chantix and Weight Gain
According to the Pfizer medication guide, which is approved by the U.S. Food and Drug Administration, weight gain is not a side effect of taking the drug Chantix. However, the guide does acknowledge that people who are taking Chantix have quit smoking or are in the process of quitting by reducing the number of cigarettes smoked each day, and the guide further acknowledges that weight gain is a side effect of nicotine withdrawal.
Weight Gain from Nicotine Withdrawal
The National Institutes of Health notes that not everyone who quits smoking gains weight. For the people who do gain weight from quitting smoking, the average weight gain is between 6 and 8 pounds. About 10 percent of people who quit smoking experience a large weight gain of 30 pounds or more.
Nicotine Withdrawal Symptoms
Because people who are taking Chantix are quitting smoking, it is useful to know the side effects of Chantix and the side effects of nicotine withdrawal. According to the National Institutes of Health, the side effects of nicotine withdrawal are insomnia, a depressed mood, an urge to smoke, anxiety, a decreased heart rate, an increased appetite or weight gain, difficulty concentrating, restlessness and irritability, frustration or anger.
Common Chantix Side Effects
The most common side effects of taking Chanitx, Pfizer reports, are nausea, which is experienced by 30 percent of the people who take Chantix, constipation, gas, vomiting and sleep problems, which includes trouble with sleeping and changes in dream patterns.
According to the National Institutes of Health, people who quit smoking may gain weight because they are more likely to feel hungrier and eat more than usual, although this typically lasts only a few weeks. Also, people who quit smoking are more likely to drink alcohol and eat snacks that are high in sugar and fats. People can gain weight, too, because cigarettes cause people to burn calories faster, so once this accelerant is removed, people burn calories at a slower rate.