Varenicline Tartrate (3 brand names, 2 dosage forms, 2 routes)
Available dosage forms: SPRAY, TABLET.
Routes of administration: NASAL, ORAL.
Brand Names
- CHANTIX
- TYRVAYA
- VARENICLINE TARTRATE
Indications and Usage
Varenicline tablets are indicated for use as an aid to smoking cessation treatment.
Contraindications
Varenicline tablets are contraindicated in patients with a known history of serious hypersensitivity reactions or skin reactions to varenicline.
Adverse Reactions
The following serious adverse reactions were reported in postmarketing experience and are discussed in greater detail in other sections of the labeling: Neuropsychiatric Adverse Events including Suicidality [see Warnings and Precautions ( 5.1 )] Seizures [see Warnings and Precautions ( 5.2 )] Interaction with Alcohol [see Warnings and Precautions ( 5.3 )] Accidental Injury [see Warnings and Precautions ( 5.4 )] Cardiovascular Events [see Warnings and Precautions ( 5.5 )] Somnambulism [see Warnings and Precautions ( 5.6 )] Angioedema and Hypersensitivity Reactions [see Warnings and Precautions ( 5.7 )] Serious Skin Reactions [see Warnings and Precautions ( 5.8 )] In the placebo-controlled premarketing studies, the most common adverse events associated with varenicline tablets (>5% and twice the rate seen in placebo-treated patients) were nausea, abnormal (vivid, unusual, or strange) dreams, constipation, flatulence, and vomiting. The treatment discontinuation rate due to adverse events in patients dosed with 1 mg twice daily was 12% for varenicline tablets, compared to 10% for placebo in studies of three months’ treatment. In this group, the discontinuation rates that are higher than placebo for the most common adverse events in varenicline tablets -treated patients were as follows: nausea (3% vs. 0.5% for placebo), insomnia (1.2% vs. 1.1% for placebo), and abnormal dreams (0.3% vs. 0.2% for placebo). Smoking cessation, with or without treatment, is associated with nicotine withdrawal symptoms and has also been associated with the exacerbation of underlying psychiatric illness.
Drug Interactions
Based on varenicline characteristics and clinical experience to date, varenicline tablets has no clinically meaningful pharmacokinetic drug interactions [see Clinical Pharmacology ( 12.3)].
Mechanism of Action
Varenicline binds with high affinity and selectivity at α4β2 neuronal nicotinic acetylcholine receptors. The efficacy of varenicline tablets in smoking cessation is believed to be the result of varenicline’s activity at α4β2 sub-type of the nicotinic receptor where its binding produces agonist activity, while simultaneously preventing nicotine binding to these receptors. Electrophysiology studies in vitro and neurochemical studies in vivo have shown that varenicline binds to α4β2 neuronal nicotinic acetylcholine receptors and stimulates receptor-mediated activity, but at a significantly lower level than nicotine. Varenicline blocks the ability of nicotine to activate α4β2 receptors and thus to stimulate the central nervous mesolimbic dopamine system, believed to be the neuronal mechanism underlying reinforcement and reward experienced upon smoking. Varenicline is highly selective and binds more potently to α4β2 receptors than to other common nicotinic receptors (>500-fold α3β4, >3,500-fold α7, >20,000-fold α1βγδ), or to non-nicotinic receptors and transporters (>2,000-fold). Varenicline also binds with moderate affinity (Ki = 350 nM) to the 5-HT3 receptor.
Overdosage
In case of overdose, standard supportive measures should be instituted as required. Varenicline has been shown to be dialyzed in patients with end-stage renal disease [see Clinical Pharmacology ( 12.3)], however, there is no experience in dialysis following overdose.