dry eye dx and tx

Effects from Antipsychotic and Antidepressant Medications

BY WILLIAM TOWNSEND, OD, FAAO

In 2008, antipsychotics and antidepressants accounted respectively for the number-one and number-five highest sales of prescription medications in the United States. These medications may secondarily block cholinergic receptors, which could reduce tear production. Many eyecare providers may be unaware of the trade and generic names of these products and of their potential effects on the ocular surface.

Antipsychotic Medications

Individuals with psychoses often exhibit personality changes and may report hallucinations or delusional beliefs accompanied by unusual or bizarre behavior. They frequently have difficulty carrying out simple daily activities. Psychotic behavior has been linked to excess levels of dopamine in the mesolimbic pathway.

Antipsychotic drugs block dopamine-2 receptors in the brain and can be very beneficial to psychotic individuals. Unfortunately, they also affect other parts of the brain and cause side effects such as extra-pyramidal symptoms of muscle spasm and stiffness, weight gain, sedation, diabetes, impotence, cognitive dulling, and arrhythmia.

Antipsychotics are grouped by time of introduction. Earlier (typical) medications tend to have more frequent and severe side effects. Some representative typical antipsychotics include haloperidol, thioridazine, Orap, fluphenazine, trifluoperazine, and chlorpromazine. Some newer-generation (atypical) antipsychotics include Abilify, Clozaril, Risperdal, Seroquel, and Zyprexa. All antipsychotics have some anticholineric effects, but the typical antipsychotics are more likely than the atypical medications to cause or exacerbate ocular dryness.

Antidepressants

Clinical depression is characterized by severe, persistent depression, loss of interest or pleasure in everyday activities, lack of appetite, chronic fatigue, and poor sleep (somnipathy). Antidepressant medications include monoamine oxidase inhibitors (Iprozid, Marplan, Nardil, Parnate), tricyclic antidepressants (amitriptyline, Sinequan, Pamelor), tetracyclic antidepressants (Asendin, Ludiomil, Remeron), selective serotonin reuptake inhibitors (Celexa, Lexapro, Prozac, Paxil, Zoloft), and serotonin-norepinephrine reuptake inhibitors (Cymbalta, Effexor, Pristiq). Each of these categories of antidepressants works a different way, and, like the antipsychotics, all exhibit some degree of anticholinergic activity and hence reduce tear production.

In the Blue Mountain Eye Study, 37 percent of all individuals identified as having dry eye were taking an antidepressant medication. In a study assessing dry eye disease in U.S. males, Schaumberg et al (2009) found a strong association between dry eye and taking antidepressants.

Anticholinergic effects may also impair individuals in many other ways. For instance, elderly individuals on antipsychotics are almost twice as likely as age-matched peers to fall. Central nervous system complications include confusion, reduced mentation, and memory impairment.

Know Your Medications

Familiarizing yourself with the brand or generic names of these medications will help you identify patients at risk for medication-related dry eye. Use of these medications should alert you to check for ocular surface changes.

I have compiled a list of the generic and trade names of commonly prescribed medications in each of these categories. You can download the list by clicking this web link. CLS

For references, please visit www.clspectrum.com/references.asp and click on document #168.

Dr. Townsend practices in Canyon, Texas and is an adjunct faculty member at UHCO. E-mail him at drbilltownsend@gmail.com.