Intranasal Varenicline: Review of a Novel Formulation for the Treatment of Dry Eye Disease.

To examine the literature pertaining to safety and efficacy of intranasal (IN) varenicline for the treatment of dry eye disease (DED). A literature search of PubMed was performed (1985 to January 2022) using the following search terms: varenicline, OC-01, intranasal, and dry eye. Additional data were acquired from references of identified articles, prescribing information, government databases, and manufacturer website. All relevant English-language studies were included in this review. IN varenicline was FDA approved for the treatment of DED in 2021. IN varenicline has demonstrated a statistically significant improvement in outcomes related to basal tear film production as measured by a Schirmer test score (STS) in data from phase 2 and 3 clinical trials. Safety data from these trials have demonstrated that IN varenicline is generally well tolerated with minimal ocular side effects. The most common side effects reported in the trials were sneezing, coughing, along with throat and nasal irritation. Patients suffering from DED have been traditionally treated with ophthalmic preparations; however, many patients struggle with proper administration of ophthalmic products. IN varenicline stimulates nicotinic cholinergic receptors and basal tear film production through the trigeminal parasympathetic nerve pathway (TPP). There is no evidence to support the long-term remission of DED symptoms with IN varenicline as seen with anti-inflammatory modulators. IN varenicline offers an effective and novel approach to management of DED for patients who desire a non-ophthalmic preparation with a favorable side effect profile.