Varenicline: What Is It and What's It For?

Varenicline is a relatively new drug that helps people quit smoking. Its overall success rate is reserved and the patient must do a lot to tackle the addiction.

Written and verified by el biólogo Samuel Antonio Sánchez Amador.

Last update: 13 August, 2021

Varenicline is a drug used to treat tobacco addiction. It reduces the need to consume nicotine, but it also reduces the rewarding effect that this drug – and other components of the cigarette – produce in the short term.

Varenicline is the active substance, but the drug is made available to the public under the trade names Champix ® and Chantix ®. It serves as an alternative option to nicotine replacement therapy in the form of patches or gum and to bupropion (Zyntabac ®).

What is varenicline used for?

To understand the mechanism of action of varenicline, first we must briefly have a look at how tobacco works on a neurological level. First of all, it should be noted that nicotine is the main component of tobacco that causes addiction.

As the BBC indicates, the nicotine in tobacco passes quickly to the lungs and reaches the brain in just 7 seconds, where it stimulates brain receptors. As a result, the release of dopamine and norepinephrine, neurotransmitters that act as behavioral reward mechanisms, is increased.

Nicotine patches and bupropion have been used historically to stop this addictive cycle, with minimal long-term effects. However, since 2006 the effects of varenicline began to be tested in a clinical setting and today it’s available to the public.

Mechanism of action

Nicotine stimulates dopamine receptors to generate addiction. The components of the brain that play an essential role in this mechanism are those located in the ventral tegmental area (VTA), as the release of dopamine in this area creates dependence.

Varenicline works by inhibiting the effects of nicotine in the brain, as indicated in Statpearls. It’s a partial agonist and blocks the nicotinic acetylcholine receptor subtypes alpha-4-beta-2, thus inhibiting the release of dopamine described above. This reduces the well-being when using tobacco and the feeling of dependency when you stop using it.

Does this drug work?

It’s necessary to clarify a couple of points regarding the usefulness of the drug. According to studies published in the journal American Family Physician, varenicline helps 1 in 11 people to quit tobacco, for at least a period of 6 months.

On the other hand, research indicates that it’s more useful than bupropion and nicotinic patches, specifically 1.4 and 1.56 times more useful, respectively. However, researchers emphasize that fewer than 20% of those who are treated with this drug keep off the habit for more than a year.

With this data we’re not saying that varenicline is useless, but rather that quitting tobacco requires a multidisciplinary approach. You may continue treatment and not get over your addiction, but don’t be discouraged. One of your attempts to quit smoking will be the last.

How is varenicline given?

This drug is prescribed only in patients 18 years of age or older. Its presentation is simple, as it’s a box with pills for oral intake.

The Champix ® information slip tells you the generalities of its dosage in the following list:

1. Before starting treatment, you must decide when you’re going to stop smoking. Generally, this should be between the 8th and the 14th of the month, if you start taking the drug at the beginning of the month — as directed. Write this date on the container as a reminder.
2. The presentations are in white tablets (0.5 milligrams of varenicline) and blue (1 milligram of varenicline). The color of the pill is important, as it indicates at what point the patient is at in the treatment.
3. Dosage from day 1 to day 3: Take one white pill (0.5 milligrams) a day.
4. Days 4-7: Take 2 white tablets a day. Ideally, one in the morning and the other in the evening.
5. Days 8-12: You should switch to the blue tablets (1 milligram), but continue taking 2 tablets a day with the same routine.
6. Day 12-end of treatment: Keep taking 2 blue pills a day.

If you have stopped smoking during the first 12 weeks of treatment, the professional may tell you to continue taking two blue pills a day for a while so as not to relapse. On the other hand, if you can’t quit, try to cut back during the first 12 weeks of varenicline treatment.

Who shouldn’t take varenicline?

The Food and Drug Administration (FDA) has recognized that, in some cases, varenicline can promote suicidal tendencies and abnormal behavior in psychologically unstable people.

This isn’t to say that the drug shouldn’t be used in people with psychiatric conditions, but it does mean that strict monitoring is required. It’s also necessary to inform the medical professional in the following cases:

1. People with cardiac symptoms: Varenicline administration can worsen cardiovascular problems, especially in older patients.
2. Seizure patients: Varenicline can cause seizures. Check with your doctor if you have a history of this.
3. Children and adolescents: The effectiveness of this medicine has not been demonstrated in children under 18 years of age.
4. Pregnancy and breastfeeding: Although the fetal toxicity of the drug hasn’t been confirmed, it is best to avoid the use of this drug during pregnancy.

What are the side effects?

Like all medications, varenicline reports certain side effects. Here they are, in order of frequency:

• Very common side effects (more than 1 in 10 people): Swelling of the nose and throat, abnormal dreams, trouble sleeping, headache, and nausea. Nausea can be avoided by starting treatment at lower doses.
• Common symptoms (up to 1 in 10 people): Sinus inflammation, weight gain, increased appetite, dizziness, changes in taste, cough, heartburn, vomiting, constipation, diarrhea, rashes, and joint pain.
• Uncommon symptoms (up to 1 in 100 people): Seizures, tremor, less sensitivity to touch, panic, trouble thinking, restlessness, ringing in the ears, red blood in stools, high blood sugar, suicidal thoughts.
• Rare side effects (up to 1 in 1000 people): Excessive thirst, slow thinking, strokes, blood in vomit, abnormal stools, coated tongue, loss of contact with reality and inability to think or judge (psychosis), skin reactions, and severe allergies.

Although all these clinical signs seem alarming, it should be noted that most patients never experience them. The most common is nausea and headaches, especially at the beginning of the treatment.

What happens if I miss a dose?

It’s important that you take the drug regularly at the same time of the day. As we’ve said, if you take one tablet it only has to be in the morning. If you take two, spread them out between breakfast and the evening.

In case you miss a dose, take it as soon as you can. But if there are less than 3 hours left before the next one, it’s best to skip it. Never take 2 dosages if you forget to take them.

How should I act in case of an overdose with varenicline?

It’s very difficult to overdose from varenicline. This drug is always compartmentalized according to the day and time of intake, so just following the instructions is enough. However, if you have taken more pills than you should, go immediately to the emergency room with the medicine packet.

If you develop any of the rare symptoms listed above – even if an overdose hasn’t occurred – immediate discontinuation of treatment is necessary. There are no reported side effects if you stop this medication abruptly.

How to store or dispose of this medicine

If the tablets are in blister form, they shouldn’t be stored above 30 degrees Celsius. Be very careful about keeping the medicine out of the reach of children.

If you want to get rid of this medicine, don’t throw it away or put it down the toilet, as this can cause great damage to the natural environment.

Varenicline: one more help to quit smoking

Verinicline can help you quit smoking. Still, you should remember that studies indicate that only 1 in 11 people (less than 10%) completely quit their habit after several months of treatment.

This doesn’t mean that the drug doesn’t work, but it does mean that the patient must provide perseverance, willpower, perseverance and a lot of self-control.

Alternatively, we recommend that you seek psychological help to address your addiction from an emotional approach. With the support of a therapist and the appropriate drugs, one of your attempts will be the successful one!