Report on Chantix Side Effects and Usage by AskDocWeb

About Chantix

What is Chantix?

Chantix is the brand name of the anti-smoking drug, Varenicline. It’s manufactured by Pfizer. Chantix is intended to help people stop smoking.

What are the Side Effects of Chantix?

The rate of side effects is controversial. The following are common side effects of Chantix therapy with the percentage of users who experience them. However, this list is not complete.

  • insomnia (37%)
  • nausea (30%)
  • abnormal dreams (19%)
  • constipation (11%)
  • gas or flatulence (10%)

Pfizer lists the following adverse events as “frequent” without giving specific percentage details:

  • abnormal liver function test
  • anxiety
  • arthralgia (neuralgic pain in a joint or joints)
  • back pain
  • chest pain
  • depression
  • diarrhea
  • disturbance in attention
  • dizziness
  • edema (excessive tissue fluid accumulation)
  • emotional disorder
  • epistaxis (nose bleed)
  • gingivitis (inflammation of the gums)
  • hot flush (hot flashes)
  • hyperhidrosis (excessive sweating)
  • hypertension
  • influenza like illness (flu)
  • irritability
  • menstrual disorder
  • muscle cramp
  • musculoskeletal pain
  • mood swings
  • myalgia (muscular pain or tenderness
  • polyuria (excessive passage of urine)
  • respiratory disorders (lungs and airways)
  • restlessness
  • sensory disturbance
  • weight increase

Tell your health care professional about side effects that bother you or that do not go away.

What are the symptoms of overdose?

If overdose is suspected, call 911 or contact your local poison control center or emergency room immediately.

Symptoms of overdose may include blurred vision, light-headedness, confusion, nausea, and seizures. Check with your doctor as soon as possible if you experience confusion, rash, itching, or seizures.

Storing Chantix

Store this medicine at room temperature, out of direct sunlight, in a tightly closed container, and out of the reach of children.

Who Should Not Take Chantix?

Chantix has not been studied in children under 18 years of age. Chantix is not recommended for children under 18 years of age.

Do not take Chantix if you are allergic to anything in it.

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your health care professional if you take:

  • insulin
  • asthma medicines
  • blood thinners

When you stop smoking, there may be a change in how these and other medicines work for you. Know the medicines you take. Keep a list of them with you to show your health care professional.

Before you start taking Chantix, tell your health care professional if you:

  • drink alcohol
  • have or had kidney problems
  • get kidney dialysis
  • are trying to become pregnant
  • are already pregnant
  • are breast-feeding

Drug Interactions

Drug interaction studies were performed with varenicline and digoxin, warfarin, transdermal nicotine, bupropion, cimetidine and metformin. No clinically meaningful pharmacokinetic drug-drug interactions have been identified by the manufacturer.

Warning Signs

Check with your doctor if you have any of the following conditions:

  • Acute syndrome of the heart
  • Aggressive behavior
  • Angina
  • Coronary artery bypass graft
  • Feeling restless
  • Depression
  • Drink alcohol to the point of intoxication
  • Feeling anger toward something
  • Having thoughts of suicide
  • Habit of drinking too much alcohol
  • Increased cardiovascular event Risk
  • Manic-Depression
  • Mood changes
  • Nausea (Feel like throwing up)
  • Peripheral vascular disease
  • Serious kidney problems
  • Schizophrenia

Chantix users report “feeling” less intoxicated when they drink alcohol. This has both positive and negative aspects. On the positive side not getting the buzz may make a person less likely to drink. On the negative side, not feeling the effects may impair the judgement for deciding when to stop consumption.

How Should I Take Chantix?

Choose a quit date when you will stop smoking.

Start taking Chantix 1 week (7 days) before your quit date. This lets Chantix build up in your body. You can keep smoking during this time.

Make sure that you try and stop smoking on your quit date. If you slip, try again. Some people need a few weeks for Chantix to work best.

Take Chantix after eating and with a full (8 ounces) glass of water.

Most people will keep taking Chantix for up to 12 weeks. If you have completely quit smoking by 12 weeks, ask your doctor if another 12 weeks of Chantix may help you stay cigarette-free.

Chantix comes as a white tablet (0.5 mg) and a blue tablet (1 mg). You start with the white tablet and then usually go to the blue tablet. Follow the dosing schedule prescribed by your health care professional.

How effective is Chantix

In clinical trials of Chantix the percentage of people still not smoking after one year ranged from 21.9% to 23%. That is an average success rate of 22% and a relapse rate of 78%.

Notes on Chantix

This medicine comes with a patient information leaflet. Read it carefully. Ask your doctor, nurse, or pharmacist any questions that you may have about this medicine.

Swallow whole. Do not break, crush, or chew before swallowing. If you are taking more than 1 dose each day, allow at least 8 hours between doses.

The FAA recently declared that pilots and air-traffic controllers may not use Pfizer’s antismoking drug Chantix, citing concerns about its effects. A new report found hundreds of cases where Chantix users experienced dizziness, loss of consciousness, seizures, and abnormal movements and spasms.

One May 8, the Associated Press reported that the drug Chantix has been linked to increased risk of suicide, but new U.S. government stop-smoking guidelines for doctors nonetheless endorse this drug.

The guidelines from the U.S. Public Health Service said that while Chantix has been linked to depression and suicidal behavior, the Pfizer product remains the most effective drug for helping people quit smoking. What they didn’t tell you is that quitting cold turkey is more effective than any drug.

Chantix Feedback

Now they tell me!
Date: 7/15/2007
Sure; Now they disclose the side effects, when its too late for me! Even my doctor was not advised of the side effects when I went on it. After going off a 3-month term of Chantix, I started getting all of these symptoms listed below. The problem is, I have been off Chantix since March, and most of the symptoms are getting progressively worse every day, even though I don’t take the drug anymore–not since 4 months ago. 4 months of agony now—when will it stop? arthralgia (neuralgic pain in all joints) back pain muscle cramps–back of legs & lower back musculoskeletal pain all over myalgia (muscular pain or tenderness gingivitis (inflammation of the gums) influenza like illness (flu) edema (very excessive tissue fluid accumulation) weight increase…. 52 pounds!! depression emotional disorder irritability *memory loss* hot flush ____ I wish I never used Chantix, I can’t move without severe pain! I just want to know if this will end any time soon. I assumed side effects would stop after stopping the Chantix, but that’s when they began. How do I get this drug out of my system? I would never recommend this drug to anyone!


Note for 9/1/2008: Lawyers have started running TV ads for clients that have suffered from acts of violence, suicidal behavior and suicide caused by the use of Chantix.

Debilitating pain
Date: 9/19/2008
Is there any way to contact a person who posted a comment on your site? On 7/15/07 a ‘J’ posted a comment regarding post usage side effects from Chantix and I have been struggling for months with the same symptoms. I wanted to contact this person to see if they have discovered anything since 7/15/07. My doctors are grasping at straws trying to diagnose this ailment and I’m still struggling, after 11 months, with debilitating pain. I give permission for you to give this person my email address, or forward my email to them, as I do understand confidentiality. Thank you,


AskDocWeb: We appreciate your understanding, your request has been forwarded to J.

Side effects are getting worse!
Date: 7/22/2009
Chantix was the “magic bullet” to get me off the smokes, but I am now in worse shape–some days I would like a bullet to the head to stop the pain! Can you forward my info to either “J” or “M” above…I need to know if anyone has found relief from the pains (side effects from Chantix) My doctor thinks I have fibromyalgia now—I am going to show her these posts—along with others I have found! I have been off Chantix for close to 3 years and the side effects are getting worse! The severe edema just showed up about 2 months ago…I am so sick of being sick! Please help! Thank you!


On the verge of divorce
Date: 10/8/2009
My husband took Chantix over a year ago, and he’s been depressed since he started taking it and his behavior became irrational, his personal and business decissions have been impaired..after 24 years of marriage, we are on the verge of divorce because life with him became unbearable…Please HELP. What can I do, he is refusing to see a Dr…Please Help.


AskDocWeb: I’m so sorry Sue, marriage counseling is beyond the scope of what we do here, which is focus on questions about side effects.

What kind of tests for memory loss?
Date: 10/28/2009
I took the drug Chantix and after taking them for about a month or so, my friends notice change in my behavior, like mood swings, hot flashes and bad dreams, and the most that I’m concerned about is my memory loss, what can I do, I didn’t even remember taking my child to get her manicure at a nice salon back in the summer, just one case that I will mention. Please help and what type of test can I take, to find out what’s going on with my memory, when I had the memory of an elephant.


AskDocWeb: You may want to have your symptoms evaluated by a neurologist or neuro-psychologist who specializes in assessing and diagnosing cognitive impairment. Your family doctor may be able to give you a referral.

Suicidal side effects
Date: 12/21/2009
Are there any cases where the suicidal side effects of chantix continue months after stopping the drug?


AskDocWeb: Although most side effects resolved shortly after discontinuing Chantix, there are a few reports of severe mood swings and suicidal thoughts lasting several months after discontinuing.

Chantix caused sexual side effects?
Date: 1/16/2010
I have been taking chantix for about 3 months and the amount of sperm when I ejaculate has gone down to a couple drops. Please help.


AskDocWeb: There are no sexual side effects listed for Chantix so you may want to check with a urologist. It is possible for an unrelated issue to develop while taking any drug.

Stopping Chantix
Date: 2/7/2010
Is their any danger in stopping chantix cold-turkey after 3 months of taking 1mg, 2x per day?


AskDocWeb: There are a few reports of severe mood swings and suicidal thoughts lasting up to 3 weeks after discontinuing Chantix. Read more feedback about Chantix.

Most recent post: April 24, 2017

If you find this page useful share it with others. If you have used Chantix, use the form below to add your review of Zyban, feedback or suggestions that may help others. Please note that all addresses are held confidential.