ATLANTA — Patients who are taking antidepressants for the first time are at greatest risk for discontinuing the therapy, Mark Vanelli, M.D., said in a poster presentation at the annual meeting of the American Psychiatric Association.
The research shows that patients are most likely to stop drug treatment at the time of their first refill, typically 30–45 days after the initiation of therapy, wrote Dr. Vanelli, chief medical officer of Adheris Inc., a Burlington, Mass., company that provides patient adherence intervention programs.
He and his associates analyzed blinded pharmacy records from 1,157 pharmacies across the country to find patients who filled prescriptions for fluoxetine, sertraline (Zoloft), paroxetine (Paxil CR), venlafaxine (Effexor XR), citalopram (Celexa), or escitalopram (Lexapro). A total of 211,565 patients filled prescriptions for the six antidepressants between Oct. 1, 2003, and March 31, 2004.
Patients were divided into two groups: rookies and veterans. Rookies (37% of the sample) were patients with no prior use of any antidepressant in the 180 days prior to the index fill; veterans (63% of the sample) were defined as patients with a history of antidepressant use in the last 180 days.
Researchers followed the patients for 360 days to calculate the number of days to therapy discontinuation. They also analyzed other factors that might contribute to discontinuation, including age, gender, index refills prescribed, copayments, and estimated income.
The median number of days to discontinuation was 67 for the rookies and 184 days for veterans. The likelihood of discontinuing therapy after the initial fill of the prescription was 39.6% for rookies and 19.9% for veterans, Dr. Vanelli reported.
Patients were considered to have discontinued therapy once they were 30 days late for a scheduled refill. Those who switched from one antidepressant to another were considered to have continued with the therapy.
Patient experience was the variable that best predicted medication discontinuation, Dr. Vanelli noted. However, older men with higher incomes and higher index refills prescribed were less likely to discontinue therapy. Higher copays also increased the risk of discontinuing therapy.
The basic trends of drug discontinuation were similar across the six antidepressants included in the study, he said.
However, one of the limitations of the study is that diagnostic information was not available so the intended duration of therapy could not be determined.
The research shows that interventions are needed to help first-time users of antidepressants with medication adherence. Some strategies to improve antidepressant compliance could include following up with rookie patients at the time of the first refill to check on medication response, insight into the illness, and refill status, Dr. Vanelli suggested.