Managing potential drug-drug interactions between gastric acid-reducing agents and antiretroviral therapy: experience from a large HIV-positive cohort.

Drug-drug interactions between antiretroviral therapy and other drugs are well described. Gastric acid-reducing agents are one such class. However, few data exist regarding the frequency of and indications for prescription, nor risk assessment in the setting of an HIV cohort receiving antiretroviral therapy. To assess prevalence of prescription of gastric acid-reducing agents and drug-drug interaction within a UK HIV cohort, we reviewed patient records for the whole cohort, assessing demographic data, frequency and reason for prescription of gastric acid-reducing therapy. Furthermore, we noted potential drug-drug interaction and whether risk had been documented and mitigated. Of 701 patients on antiretroviral therapy, 67 (9.6%) were prescribed gastric acid-reducing therapy. Of these, the majority (59/67 [88.1%]) were prescribed proton pump inhibitors. We identified four potential drug-drug interactions, which were appropriately managed by temporally separating the administration of gastric acid-reducing agent and antiretroviral therapy, and all four of these patients remained virally suppressed. Gastric acid-reducing therapy, in particular proton pump inhibitor therapy, appears common in patients prescribed antiretroviral therapy. Whilst there remains a paucity of published data, our findings are comparable to those in other European cohorts. Pharmacovigilance of drug-drug interactions in HIV-positive patients is vital. Education of patients and staff, and accurate data-gathering tools, will enhance patient safety.

Prevalence and type of drug-drug interactions involving ART in patients attending a specialist HIV outpatient clinic in Kampala, Uganda.

OBJECTIVES: Scale-up of HIV services in sub-Saharan Africa has rapidly increased, necessitating evaluation of medication safety in these settings. Drug-drug interactions (DDIs) involving antiretrovirals (ARVs) in sub-Saharan Africa are poorly characterized. We evaluated the prevalence and type of ARV DDIs in Ugandan outpatients and identified the patients most at risk. METHODS: A total of 2000 consecutive patients receiving ARVs at the Infectious Diseases Institute, Kampala were studied. The most recent prescription for each patient was screened for clinically significant DDIs using www.hiv-druginteractions.org. Univariable and multivariable logistic regression were used to identify risk factors for DDIs. A screening tool was developed using significant risk factors and tested in a further 500 patients. RESULTS: Clinically significant DDIs were observed in 374 (18.7%) patients, with a total of 514 DDIs observed. Only 0.2% of DDIs involved a contraindicated combination. Comedications commonly associated with DDIs were antibiotics (4.8% of 2000 patients), anthelmintics (2.2%) and antifungals (3.5%). Patient age, gender, CD4 count and weight did not affect risk of DDIs. In multivariable analysis, the patient factors that independently increased risk of DDIs were two or more comedications (P < 0.0001), a PI-containing ARV regimen (P < 0.0001), use of an anti-infective (P < 0.0001) and WHO clinical stage 3-4 (P = 0.04). A scoring system based on having at least two of these risk factors identified between 75% and 90% of DDIs in a validation cohort. CONCLUSIONS: Significant ARV DDIs occur at similar rates in resource-limited settings and developed countries; however, the comedications frequently causing DDIs differ. Development of tools that are relevant to particular settings should be a priority to assist with prevention and management of DDIs.

The clinical utility of HIV outpatient pharmacist prescreening to reduce medication error and assess adherence.

Antiretroviral therapy (ART) is complex and has high propensity for medication error and drug-drug interactions (DDIs). We evaluated the clinical utility of pharmacist prescreening for DDIs, adherence to ART and medicines reconciliation prior to HIV outpatient appointments. A pharmacist took detailed medication histories and ART adherence assessments, then screened medication for DDIs. A template detailing current medication, potential DDIs and adherence was filed in the clinical notes and physicians were asked for structured feedback. Potential DDIs were observed in 58% of 200 patients, with 22 (9%) potential DDIs occurring with medication that was not previously recorded in the patients' notes. Of 103 physician responses, 61.2% reported that the pharmacist consultation told them something they did not know, and pharmacist consultants led to change in management in 13.6% of cases. Pharmacist consultations were more likely to add benefit in patients taking two or more concomitant medications in addition to ART (P = 0.0012).

Patients accessing HIV treatment via sexual health services: what are the risks of the dual case-note system?

In many British hospitals, HIV-positive patients access care via genitourinary (GU) medicine services. As a result of National Health Service (NHS) legislation, such patients may have information concerning HIV treatment filed separately from their general clinical records. We sought to evaluate accuracy of medication records of patients with both GU medicine and general hospital case-notes, and to assess clinical risk arising from incorrect or incomplete recording. In this retrospective review, 156 episodes of care from 100 HIV-positive patients with separate HIV case-notes were evaluated for accuracy of medication recording, when paired with clinical notes from attendances in other hospital departments. Discrepancies were observed in 52.6% of care episodes; significant discrepancies were apparent in 7.8%. The dual case-note system represents significant risk to patient care. We recommend that hospitals that continue to operate this system urgently consider amalgamation of HIV care records into hospital case sheets, in line with current national standards.