Varenicline is a medication primarily used to help people quit smoking. It works by reducing withdrawal symptoms and cravings associated with quitting smoking. Varenicline is a partial agonist at nicotine receptors in the brain, which means it both stimulates these receptors to a lesser extent than nicotine itself and blocks nicotine from fully activating them. This dual action helps reduce the rewarding effects of nicotine and makes smoking less pleasurable.

Varenicline is typically taken orally in pill form. It's usually started one to two weeks before the planned quit date, and the dosage may be gradually increased over the first week of treatment. The standard course of treatment is 12 weeks, but in some cases, it may be extended for another 12 weeks to improve the chances of quitting successfully.

Varenicline (Chantix) blocks the mesolimbic dopamine system activation brought on by nicotine addiction.

It is used in the treatment of smoking cessation.

E-Cigarettes once thought to become a good aid for the cessation of smoking, are now considered more harmful. Recently, a lot of patients have developed serious lung diseases from its use. It is also considered a gateway to addiction.

Chantix (Varenicline) Dose in Adults

Chantix (Varenicline) Dose in the treatment of Smoking cessation:

It is not available over the counter.

Starting Dosage:

• For the first 3 days, take 0.5 mg once a day.
• Then, for the next 4 days (days 4 to 7), take 0.5 mg twice a day.

Continued Treatment (After Day 7):

• From Day 8 onward, take 1 mg twice a day.
• Keep taking this dosage for 11 weeks.

Adjustments:

• If you're having trouble with the usual dose, your doctor might suggest lowering it temporarily or permanently.

Note:

• Start taking varenicline one week before you plan to quit smoking.
• You can also start it up to 35 days before your quit date.
• Some studies show that starting earlier might help you quit better.
• If you're not ready to quit right away, you can start varenicline and slowly cut down on smoking over 12 weeks until you stop completely.
• If you quit successfully after 12 weeks, you might keep taking varenicline for another 12 weeks to help you stay smoke-free.
• If you've tried to quit before but it didn't work, or if you start smoking again after treatment, it's okay to try varenicline again once you figure out what went wrong last time.

Chantix (Varenicline) Dose in Children

Not recommended for use in children. 

Pregnancy Risk Factor: C

• The information about using varenicline during pregnancy is limited.
• Nicotine, which is found in both cigarettes and varenicline, can cause problems for both the mother and the baby during pregnancy.
• It's important for pregnant women to try to quit smoking, but there isn't enough evidence to say if varenicline is safe to use for quitting smoking while pregnant.
• So, it's best for pregnant women to avoid using varenicline for quitting smoking unless their doctor thinks it's absolutely necessary.

Varenicline (Chantix) use during breastfeeding:

• It's uncertain if varenicline is present in breast milk.
• Because there isn't enough information, it's not recommended for breastfeeding women to use varenicline to quit smoking.
• If a breastfeeding mother is considering using varenicline, she should talk to her doctor about the risks and benefits.
• The manufacturer suggests deciding whether to stop breastfeeding or stop taking the medication, considering how important the treatment is for the mother.
• Infants exposed to varenicline through breast milk should be watched for seizures or excessive vomiting.

Chantix dose in kidney disease:

• For severe kidney impairment, the starting dose is 0.5 mg once daily, with a maximum of 0.5 mg twice daily. If you're on hemodialysis, the maximum dose is 0.5 mg once daily.
• If your kidney function is severely reduced (CrCl <30 mL/minute) or if you have end-stage renal disease and are receiving hemodialysis, your doctor may adjust your dosage.
• If your kidney function is normal or moderately reduced (CrCl ≥30 mL/minute), you don't need to change the dosage of varenicline.

Varenicline Dose in liver disease:

• No dosage adjustment is needed for individuals with hepatic impairment when taking varenicline.

Common Side Effects of Varenicline (Chantix) Include:

• Gastrointestinal:
  • Vomiting
  • Nausea
• Central Nervous System:
  • Abnormal Dreams
  • Irritability
  • Headache
  • Insomnia
  • Suicidal Ideation
  • Depression

Less Common Side Effects of Varenicline (Chantix) Include:

• Dermatologic:
  • Skin Rash
• Cardiovascular:
  • Peripheral Edema
  • Myocardial Infarction
  • Angina Pectoris
  • Chest Pain
• Respiratory:
  • Dyspnea
  • Upper Respiratory Tract Infection
  • Rhinorrhea
• Central Nervous System:
  • Agitation
  • Sleep Disorder
  • Anxiety
  • Malaise
  • Tension
  • Lethargy
  • Nightmares
  • Drowsiness
  • Hostility
• Gastrointestinal:
  • Increased Appetite
  • Anorexia
  • Dysgeusia
  • Abdominal Pain
  • Diarrhea
  • Flatulence
  • Constipation
  • Xerostomia
  • Dyspepsia
  • Decreased Appetite
  • Gastroesophageal Reflux Disease

Contraindication to Varenicline (Chantix) Include:

• If you've had a serious allergic reaction or skin reaction to varenicline or any ingredient in the medication, you should avoid using it.
• Serious hypersensitivity reactions can include severe allergic responses like difficulty breathing or swelling of the face, lips, tongue, or throat.
• Skin reactions may include rash, itching, or blistering.

Warnings and precautions

CNS depression:

• Varenicline can cause central nervous system (CNS) depression, which might make it harder for you to stay alert or think clearly.
• This means you should be careful when doing activities that need mental focus, like driving or operating machinery.
• There have been reports of traffic accidents and other injuries in people taking varenicline, so it's essential to be cautious until you know how the medication affects you.
• If you experience any drowsiness or difficulty concentrating while taking varenicline, it's best to avoid tasks that require mental alertness until you feel better.

Hypersensitivity reactions

• Varenicline has been associated with hypersensitivity reactions, including angioedema, and in rare cases, serious skin reactions like Stevens-Johnson syndrome and erythema multiforme.
• If you experience signs or symptoms of a hypersensitivity reaction, such as swelling of the face, lips, tongue, or throat, or if you develop a severe skin rash or blistering, stop taking varenicline immediately.

Nausea:

• Nausea is a common side effect of varenicline, and it can vary in intensity from person to person.
• Some people may experience it briefly, while others may have persistent nausea.
• If you find the nausea intolerable, talk to your doctor about the possibility of reducing your dosage.

Neuropsychiatric effects

• Varenicline has been associated with reports of serious neuropsychiatric events, such as depression, suicidal thoughts, and suicide, in both people with and without preexisting psychiatric conditions.
• Some of these cases may have been complicated by symptoms of nicotine withdrawal after quitting smoking.
• However, controlled trials have not found significant differences in neuropsychiatric effects between varenicline, bupropion, nicotine patches, or placebo.
• It's important to monitor all patients taking varenicline for behavioral changes and psychiatric symptoms, such as agitation, depression, or suicidal thoughts.

Somnambulism:

• Cases of somnambulism, or sleepwalking, with varenicline have been reported, and in some instances, individuals engaged in harmful behavior to themselves, others, or property while sleepwalking.
• If you experience somnambulism while taking varenicline, it's important to discontinue the treatment and seek medical advice promptly.
• Sleepwalking can potentially lead to dangerous situations, and it's crucial to address this side effect to ensure your safety and the safety of others around you.

Cardiovascular events

• There is evidence suggesting that varenicline treatment might increase the risk of cardiovascular events.
• A meta-analysis of 15 clinical trials, including one with a placebo group consisting of patients with stable cardiovascular disease, found a slightly higher incidence of major cardiovascular events (such as cardiovascular-related death, nonfatal heart attack, and nonfatal stroke) in patients using varenicline compared to those on placebo.
• However, these events were rare in both groups, and the difference did not reach statistical significance, though the data was consistent.
• Most events occurred in patients already known to have cardiovascular disease.
• Interestingly, the analysis also showed a trend toward lower all-cause and cardiovascular mortality in varenicline-treated patients, though this wasn't statistically significant either.

Renal impairment

• Varenicline should be used cautiously in patients with renal impairment, especially those with severe impairment.
• In cases of severe renal impairment, dosage adjustment is necessary.
• This means that if you have kidney problems, particularly severe ones, your doctor may need to adjust the dose of varenicline to ensure it is safe and effective for you.

Seizures:

• Seizures have been reported in patients taking varenicline, both in those with a history of seizures and in those without.
• These seizures typically happen within the first month of starting therapy.
• Before prescribing varenicline to patients with a history of seizures or other factors that might lower the seizure threshold.

Varenicline: Drug Interaction

Monitor:

• Be Alert: Keep an eye out for changes in behavior or mood.
• Watch for Symptoms: Look for signs like agitation, depression, or thoughts of self-harm.
• Stay Aware: Be mindful of any unusual thoughts or actions.
• Communicate: Let your healthcare provider know immediately if you notice any concerning symptoms.
• Seek Help: If you or someone you know experiences suicidal thoughts or behavior, seek help right away.

How to administer Varenicline (Chantix)?

• Take with Food: Always take varenicline after eating.
• Full Glass of Water: Swallow the pill with a full glass of water.
• Consistency is Key: Take it the same way every time to ensure effectiveness.

Mechanism of action of Varenicline:

• Varenicline works by partially activating certain receptors in the brain that are involved in nicotine addiction, called α4 β4 nicotinic receptors.
• By doing this, it blocks nicotine from fully stimulating these receptors, which reduces the rewarding feeling you get from smoking.
• It also binds to another type of receptor called the 5-HT receptor, although we're not exactly sure how this affects things.
• While varenicline does stimulate dopamine activity like nicotine does, it does so to a much lesser extent, which helps decrease cravings and withdrawal symptoms associated with quitting smoking.

Absorption:

• Gets into your body well, and it doesn't matter if you take it with or without food.

Protein Binding:

• Only a small amount sticks to proteins in your body.

Metabolism:

• Very little of it gets broken down in your body, less than 10%.

Bioavailability:

• About 90% of the drug you take ends up working in your body.

Half-life:

• It takes about 24 hours for half of the drug to leave your body.

Time to Peak:

• The highest amount in your blood happens around 3 to 4 hours after you take it.

Excretion:

• Most of it leaves your body through urine, and about 92% of it is still the same drug as when you took it.

International Brands of Varenicline:

• Chantix
• Chantix Continuing Month Pak
• APO-Varenicline
• Champix
• Champix Starter Pack
• TEVA-Varenicline
• Chantix Starting Month Pak
• Champix
• Varni

Varenicline brands in Pakistan: