to the editor: Drs. Gurvich and Cunningham state in their article¹ on psychotropic drugs in nursing homes that fluoxetine (Prozac) is not recommended in the geriatric population because of its longer half-life of active metabolite relative to other selective serotonin reuptake inhibitors (SSRIs), resulting in the potential for a longer duration of side effects.

While it is true that fluoxetine's active metabolite has a half-life of up to 16 days, because of its low incidence of side effects compared with other SSRIs, it has a very low discontinuation rate compared with paroxetine (Paxil), fluvoxamine (Luvox) and sertraline (Zoloft).² Furthermore, because fluoxe-tine has a longer half-life, a missed dose is not as significant as it is with other SSRIs, and fluoxetine is not associated with the discontinuation syndrome that is found with other SSRIs.³ Fluoxetine should not be avoided in the geriatric population and may even be the drug of choice for selected patients.

in reply: We agree that selected geriatric patients respond well to fluoxetine. In fact, the U.S. Food and Drug Administration (FDA) recently approved labeling for fluoxetine to be used to treat patients with depression in the geriatric population.

A placebo-controlled study¹ that contributed to this recent FDA approval evaluated 671 geriatric patients with major depression. The study concluded that 20 mg per day of flu-oxetine is more effective than placebo and is as equally well tolerated as placebo. However, the patients participating in the study were out-patients, an average age of 67 years and were considerably younger and healthier than patients in a typical skilled nursing facility.

Our article² focused on the more frail elderly patient who often responds differently to medications. Dosing titration of fluoxetine must be done carefully in this population: “The long half-lives of fluoxetine and norfluoxetine promote insidious drug accumulation, which takes considerable time to correct.”³ One way to use the long half-life to advantage, however, would be to dose fluoxetine every other day, thus reducing the risk of side effects and accumulation without compromising drug effectiveness.

Another issue to consider is drug interactions. Patients in skilled nursing facilities are often given multiple medications, and causing new drug interactions is a constant concern. Fluoxetine and its metabolite are more potent P450 inhibitors than sertraline, and citalopram (Celexa) appears to inhibit the P450 minimally, if at all.^3,4 Clearly, drug selection is dependent on the practitioner's clinical experience and individual patient's tolerance of a given medication.