Background: In a previous study, we found that past medication use was associated with medication adherence in patients prescribed atypical antipsychotics.
Objective: The present study aimed to determine whether past medication experience was associated with adherence in patients prescribed selective serotonin reuptake inhibitors and serotonin-norepinephrine reuptake inhibitors.
Methods: Deidentified computerized pharmacy records of patients from 1157 pharmacies throughout the United States were used to select patients who were dispensed extended-release venlafaxine, controlled-release paroxetine, sertraline, fluoxetine, escitalopram, and/or citalopram between October 1, 2003, and March 31, 2004. Patients who were dispensed an antidepressant during this enrollment period were stratified into 2 groups. One group consisted of patients to whom an antidepressant medication had not been dispensed in the 180-day period prior to the index date. The other group was composed of individuals who had been dispensed an antidepressant during that period. Discontinuation was defined as being > or =30 days late for a scheduled refill. Adherence was measured using Kaplan-Meier analysis during a 360-day follow-up period.
Results: Of 211,565 patients analyzed, 38.5% had not received an antidepressant previously; 74.0% of the total sample were women. The mean age was 50.5 years. The median times to medication discontinuation were 67 days in patients not previously dispensed an antidepressant and 184 days in those who were. Discontinuation in the first 30 days was observed in 38.8% of patients not previously dispensed an antidepressant and in 18.8% of those who were.
Conclusions: Prior antidepressant receipt rather than the use of a particular medication was associatedwith antidepressant adherence in this analysis. Patients without prior antidepressant receipt faced twice the risk for discontinuation during the first 30 days of treatment.