OBJECTIVES

Drug-drug interactions (DDIs) in patients taking antiretrovirals (ARVs) are prevalent globally (14-41%). Data from Uganda using HIV clinic records alone show a prevalence of clinically-significant DDIs (CSDDIs) of 18.9%. Clinical pharmacist input is often lacking in HIV outpatient services, due to cost and availability. We aim to evaluate utility and feasibility of a novel DDI screening strategy, and the cost implications of a task-shifting ‘hub and spoke’ approach.

METHODS

As part of an ongoing longitudinal study, trained pharmacy technicians at three diverse clinics obtained medication histories using patient interview, clinical notes and prescriptions. Information was transferred via secure mobile upload to an ARV information resource (ATIC), where a pharmacist screened for DDIs using www.hiv-druginterctions.org, and generated feedback for prescribers. Prescribers from two sites assessed the service via anonymous questionnaire. A time-motion survey and local salary scales informed initial cost assessment.

RESULTS

Of 500 patients, 131(26.2%, 95%CI 22.3-30.05%) had ≥1 CSDDI. Prescribers were aware of 6 (4.6%) CSDDIs (131 responses, 181 CSDDIs detected). Prescribers reported that DDI checks provided ‘new information’ in 60.2% of cases, and they ‘changed clinical management’ for 55.6% of DDIs, as a result. DDI screening reportedly ‘saved prescribers time’ in 68.6% of cases and overall ‘added benefit’ in 74.8%. A full-time pharmacy technician could screen >3000 patients in 12 months. One full-time pharmacist in a ‘hub’ centre could screen for DDIs for 5 ‘spoke’ clinics. Employing pharmacy technicians at 5 clinics, plus one pharmacist would cost $29,000. annually. In contrast, a full-time pharmacist at each of the 5 sites would cost $48,000.

CONCLUSIONS

The novel DDI screening strategy was feasible and prescribers reported it added benefit in >70% of cases. CSDDI prevalence may be underestimated in the absence of full medication lists. Task shifting using a ‘hub and spoke’ DDI screening model had lower costs than a standard pharmacist-led service.