Patient compliance with enteric-coated weekly fluoxetine during continuation treatment of major depressive disorder.

BACKGROUND

A once-weekly enteric-coated formulation of fluoxetine represents a new, effective option for the long-term treatment of clinically diagnosed depression. This study assessed compliance with the new once-weekly fluoxetine as compared with once-daily fluoxetine treatment.

METHOD

Adult patients from the United Kingdom who had responded to fluoxetine treatment for a current episode of depression (DSM-IV criteria) were monitored for compliance with daily and weekly dose administration of fluoxetine. The study consisted of 2 study phases. Study phase I was a baseline assessment of 20 mg of fluoxetine daily dosing for 4 weeks (N = 117). The second phase of the study consisted of randomly assigning patients to either once-weekly (90 mg/wk) or once-daily (20 mg/day) fluoxetine for 3 months (weekly, N = 56; daily, N = 53). Compliance with the dosing regimen was measured using an electronic Drug Exposure Monitor (eDEM, AARDEX Ltd., Zug, Switzerland).

RESULTS

For those patients randomly assigned to weekly fluoxetine, compliance was 85.4% during study period I while on treatment with daily fluoxetine and then 87.5% while on treatment with weekly fluoxetine. This difference was not significant. For once-daily dosing, however, compliance declined from 87.3% during period I to 79.4% during period II (p < .001). After adjusting for compliance during study period I, weekly compliance during study period II was 87.8% and daily compliance was 79.0%, a statistically significant difference (p = .006).

CONCLUSION

Compliance with once-weekly fluoxetine was better than that with once-daily fluoxetine. Compliance decreased over time when patients remained on daily dosing; however, when patients switched from daily dosing to weekly dosing, compliance did not decrease. The results of this study allay concerns about inferior compliance with a once-weekly regimen compared with the conventional once-daily regimen.