Varenicline (Chantix) is a prescription oral medication used to help adults quit smoking. It works by targeting specific nicotine receptors in the brain. The drug reduces the pleasurable effects of smoking and lessens the severity of withdrawal symptoms. Adherence to the prescribed regimen is necessary for effectiveness and to minimize potential adverse reactions.
The Standard Dosing Schedule
The standard course of treatment for varenicline begins with a gradual increase in dose, known as titration. This process helps reduce dose-related side effects, particularly nausea. Dosing typically starts one week before the individual’s planned date to stop smoking.
The initial phase lasts seven days, beginning with a low dose. For the first three days, the patient takes 0.5 mg once daily. The dose then increases for the next four days (Days 4 through 7) to 0.5 mg taken twice daily, once in the morning and once in the evening.
The full therapeutic dose begins on Day 8. From Day 8 onward, the dose is increased to 1 mg taken twice daily. Patients are encouraged to set a “quit date” between days 8 and 35 of treatment, allowing the medication time to reach effective levels before stopping smoking completely.
Handling Missed Doses and Treatment Duration
Specific instructions exist for managing missed doses of varenicline. If a dose is forgotten, the patient should take it as soon as they remember. However, if it is almost time for the next scheduled dose, the missed dose should be skipped entirely.
Never take two doses at the same time to compensate for a forgotten one, as this increases the risk of side effects. The initial course of varenicline treatment is typically twelve weeks, aiming to help the patient achieve and maintain abstinence from smoking.
For individuals who successfully stop smoking by the end of the initial twelve weeks, an additional twelve weeks of maintenance therapy may be recommended. This extended treatment has been shown to further increase the likelihood of long-term abstinence. The decision to continue the medication beyond the initial period should always be made in consultation with a physician.
Dose Adjustments for Specific Patients
While the standard 12-week schedule is common, certain patient factors necessitate a deviation to ensure safety and effectiveness. Since the body eliminates varenicline almost entirely through the kidneys, patients with impaired renal function require a modified dosage. Individuals diagnosed with severe kidney problems, indicated by a creatinine clearance of less than 30 mL/min, must have their dose reduced.
For these patients, the recommended starting dose is 0.5 mg once daily. The maximum daily dose is capped at 0.5 mg taken twice a day. This lower dosage prevents the drug from accumulating in the bloodstream to potentially harmful levels. Dose adjustments may also be necessary for patients who experience severe, intolerable side effects, even with normal kidney function.
If a patient reports significant adverse reactions, such as severe nausea or persistent insomnia, the physician may temporarily or permanently reduce the dose. The dose is often lowered to 0.5 mg twice daily to improve tolerability. This modification allows the patient to continue treatment at a manageable level, supporting smoking cessation.