What are the common side effects of Chantix? How can you avoid them? Get the answers to these questions and more in this comprehensive article.

Common Chantix Side Effects

Chantix (varenicline) is a prescription medication used to help people quit smoking. While it can more than double the chance of success in quitting smoking, Chantix does come with some side effects that users should be aware of. The most common side effects of Chantix include:

• Nausea, vomiting, upset stomach, appetite change, or abdominal pain
• Flatulence, diarrhea, or constipation
• Dry mouth or taste disturbance
• Insomnia, abnormal dreams, or sleep disorder
• Malaise, fatigue, or somnolence (sleepiness)
• Headache
• Emotional disturbance
• Shortness of breath or respiratory disorders
• Skin rash

Nausea with Chantix

The most common adverse reaction to Chantix is nausea, which studies have estimated to occur in about 25% of individuals. Typically, the nausea is mild, occurs within the first two weeks, and often resolves with time. If the nausea is persistent or worsening, or if it is accompanied by vomiting, it is recommended to consult your prescriber for medical advice.

Appetite Change with Chantix

One of the biggest concerns among smokers who are considering quitting is the potential for weight gain. While weight gain after stopping smoking averages five to 10 pounds, individual experiences can vary considerably. In fact, about 20% of those who quit may lose weight. Chantix users may actually experience either an increase or decrease in appetite, but neither one occurs in more than 5% of users. Ultimately, Chantix does not seem to significantly affect the chance of weight gain with smoking cessation.

Vivid Dreams and Nightmares with Chantix

A variety of sleep-related disturbances have been described with Chantix. These disturbances can range from unusual dreams to trouble sleeping. Most commonly, abnormal dreams are experienced by about 10% of those taking the drug, and nightmares or sleep disorders are reported by another 1% to 3%. Small numbers of case reports have described sleepwalking that involved harmful activities. Sleep problems may also be an aspect of nicotine withdrawal after quitting smoking.

Serious Side Effects of Chantix

In addition to the common side effects, Chantix has also been associated with some more serious side effects, including:

• Depression or neuropsychiatric disorder
• Suicidal behavior or thoughts
• Homicidal thoughts
• Hypersensitivity allergic reaction or angioedema (swelling of the face or body)
• Serious skin reactions such as Stevens-Johnson Syndrome (includes blisters and peeling skin) or erythema multiforme
• Arrhythmia (heart rhythm problem), heart attack, stroke, or angina (chest discomfort)
• Seizure
• Photosensitivity (light sensitivity)
• Vision changes
• Anemia or thrombocytopenia (low platelet or clotting cell count)
• Kidney stones or kidney failure
• Gastrointestinal bleeding
• Pancreatitis (pancreas inflammation)
• Hypokalemia (low potassium level)

Depression and Chantix

Case reports of depressed mood and even suicidal thoughts and aggressive behavior came to light after the release of Chantix. The Food and Drug Administration (FDA) responded by adding a black box warning on Chantix in 2009 about this risk. A subsequent study examined these potential concerns in detail and did not find an elevated risk of these adverse effects compared to other smoking cessation medications or even a placebo. The FDA removed the black box warning from Chantix in 2016.

Cardiovascular Side Effects of Chantix

Chantix has labeling that warns about use by those with known cardiovascular disease. The labeling arose due to some study data showing a small increased risk of life-threatening cardiovascular events with Chantix. An analysis of multiple clinical trials did not corroborate this concern, however, as rates of cardiovascular events were similar between those taking and not taking Chantix. Furthermore, the FDA concluded that the overall benefits of Chantix outweigh the potential risks for most smokers, including those with cardiovascular disease.