The role of medications in causing dry eye.

The purpose of this paper is to review the possible role of polypharmacy in causing dry eye disease (DED), reflecting the complex interactions and complications associated with the use of multiple systemic and topical ocular medications. The pharmacological, physiological, anatomical, and histological mechanisms causing dry mouth differ little from those causing dry eye. Oral polypharmacy is the most common cause of dry mouth, but has not been investigated as a cause of dry eye. Topical ocular polypharmacy has been shown to cause DED. Information on drugs that likely cause or aggravate DED and the controversial role of preservatives in topical ocular medications are examined. Systemic or topical ocular medications and preservatives used in topical ocular drugs may cause dry eye through the drug's therapeutic action, ocular surface effects, or preservatives, and the effects probably are additive. Long-term use of topical ocular medications, especially those containing preservatives such as BAK, may play an important role in DED and the role of polypharmacy needs further study. We review possible ways to decrease the risk of medication-related dry eye.