The VA National Center for Medication Safety has been established by the National Center for Patient Safety and Pharmacy Benefits Management Services to help manage the risks of medications prescribed by VA healthcare providers. Drug safety communications concerning serious new adverse drug events along with guidance for changes in practice to reduce the risk are widely distributed via local Directors to applicable staff of all VA healthcare systems. Beginning in August 2011, FDA and commensurate VA national safety bulletins were issued for citalopram, a very commonly prescribed antidepressant medication. The safety bulletins recommended that doses should no longer exceed 40 milligrams per day due to concerns about newly recognized, potentially life threatening cardiac side effect. An electronic review of VA prescription records indicated that more than 265,000 Veterans were being treated with citalopram when the new safety warning was issued. Approximately 20 percent had prescriptions that exceeded the new safety limit for citalopram doses.
To study the impact of the citalopram drug safety bulletin on subsequent VA prescribing practices and to compare the incidence of hospitalizations and mortality when higher doses of citalopram were or weren't reduced to 40 milligrams per day or less.
Existing electronic data bases available via the VA Informatics and Computing Infrastructure, VINCI, were utilized to conduct a retrospective cohort study. Prescription records for citalopram were used to ascertain and track Veterans who were receiving citalopram prescriptions for a daily dose of more than 40 milligrams prior to dissemination of the safety bulletins. Veterans were followed for 12 months to determine whether and when their prescribed citalopram dose was reduced, hospitalizations and mortality.
A search of electronic medical records found 42,046 patients (age 58 11 years, 92% male) whose last citalopram prescription filled prior to the safety bulletins exceeded 40, averaging 64 milligrams per day. Within 180 days, 60 percent had filled prescriptions for doses that were reduced to less than 40 milligrams per day. Health care encounters, diagnoses, prescription medications and citalopram use in the year prior to entering the study cohort were similar in the groups that subsequently did or didn't have their doses reduced as stipulated by the safety bulletin. The incidence of all-cause hospitalization or death was significantly higher after dose reductions (adjusted hazard ratio 4.5 (95% confidence interval 4.1 - 5.0; p < 0.001) as was the incidence of hospitalizations for depression or all-cause death (adjusted hazard ratio 2.2 (1.8 - 2.6; p < 0.001). Mortality wasn't reduced (adjusted hazard ratio 1.0 (0.8 - 1.3; p=0.85) nor was hospitalizations for arrhythmias or all-cause death (adjusted hazard ratio 1.3 (1.0 - 1.7; p =0.02). Stipulating a safety limit for citalopram doses appears to have had unintended clinical consequences.
This evaluation helped fill an important gap in information about the impact of an exemplary drug safety communication on outcomes in the VA patient population. Hopefully, the results will prompt policymakers to consider potential harms before stipulating, rather than recommending actions to mitigate an unquantified risk when the actions are contrary to common clinical practices.
- Rector TS, Adabag S, Cunningham F, Nelson D, Dieperink E. Outcomes of Citalopram Dosage Risk Mitigation in a Veteran Population. The American journal of psychiatry. 2016 Sep 1; 173(9):896-902.