Mark E. Schmidt, Maurizio Fava, James M. Robinson, and Rajinder Judge
Background: A simple, once-weekly dosing
regimen could be a convenient alternative for many patients
during long-term treatment of depression. Such a strategy might
also be effective for improving medication compliance and the
outcome of continuation treatment. The safety and effectiveness
of a new formulation of enteric-coated fluoxetine (90 mg) given
once weekly was tested during the continuation treatment of major
depressive disorder.
Method: Patients meeting DSM-IV criteria
for major depressive disorder with modified 17-item Hamilton
Rating Scale for Depression (HAM-D-17) scores >= 18
and Clinical Global Impressions-Severity of Illness scale (CGI-S)
scores >= 4 were treated 13 weeks with open-label 20 mg/day of
fluoxetine in a multicenter U.S. study. Responders (N = 501) were
randomly assigned to receive 20 mg of fluoxetine daily, placebo,
or 90 mg of enteric-coated fluoxetine weekly for 25 weeks of
double-blind continuation treatment. The primary efficacy measure
was the percentage of patients who relapsed. Time to relapse was
tested over the 25-week continuation period using log-rank
analyses of the Kaplan-Meier estimates of relapse rates.
Additional analyses of efficacy included comparison of change
from baseline to endpoint for the HAM-D-17, CGI-S, and HAM-D-28
subscales by last observation carried forward (LOCF). Safety
measures included comparison of treatment-emergent adverse
events, both spontaneous and solicited (using the Association for
Methodology of Documentation in Psychiatry-Module 5), vital
signs, and laboratory measures.
Results: Relapse rates for patients
assigned to fluoxetine, either 20 mg daily or 90 mg weekly, were
significantly lower than for placebo by log-rank analysis and
LOCF analyses of secondary efficacy measures. Efficacy did not
significantly differ between the 2 active drug groups by these
measures. Enteric-coated fluoxetine at a once-weekly dose of 90
mg was well tolerated, and its safety profile was similar to that
of daily 20 mg of fluoxetine.
Conclusion: The formulation of
enteric-coated fluoxetine taken once weekly is effective, safe,
and well tolerated for continuation treatment of depression in
patients who responded to acute treatment with 20 mg/day of
fluoxetine. Monitoring during long-term treatment for evidence of
sustained remission is important regardless of dosing regimen.
J Clin Psychiatry 2000;61(11):851-857
© Copyright 2000 Physicians Postgraduate Press, Inc.