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, effectiveoption for the long-term treatment of clinically diagnosed depression. This study assessed compliancewith 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 ofdepression (DSM-IV criteria) were monitored for compliance with daily and weekly dose administrationof fluoxetine. The study consisted of 2 study phases. Study phase I was a baseline assessment of 20mg of fluoxetine daily dosing for 4 weeks (N = 117). The second phase of the study consisted of randomlyassigning patients to either once-weekly (90 mg/wk) or once-daily (20 mg/day) fluoxetine for 3months (weekly, N = 56; daily, N = 53). Compliance with the dosing regimen was measured using anelectronic Drug Exposure Monitor (eDEM, AARDEX Ltd., Zug, Switzerland). Results: For thosepatients randomly assigned to weekly fluoxetine, compliance was 85.4% during study period I while ontreatment with daily fluoxetine and then 87.5% while on treatment with weekly fluoxetine. This differencewas not significant. For once-daily dosing, however, compliance declined from 87.3% during periodI to 79.4% during period II (p < .001). After adjusting for compliance during study period I, weeklycompliance during study period II was 87.8% and daily compliance was 79.0%, a statistically significantdifference (p = .006). Conclusion: Compliance with once-weekly fluoxetine was better than thatwith 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. Theresults of this study allay concerns about inferior compliance with a once-weekly regimen comparedwith the conventional once-daily regimen.