Perpetrator Characteristics of Azole Antifungal Drugs on Three Oral Factor Xa Inhibitors Administered as a Microdosed Cocktail.

BACKGROUND: Factor Xa inhibitors (FXaIs) are increasingly used without having sufficient drug-drug interaction data. Using a microdosed cocktail methodology could support filling the knowledge gap quickly. METHODS: In a randomised crossover trial, we investigated the drug-drug interactions between six oral azole antifungals and a microdosed FXaI cocktail containing 25 µg rivaroxaban, 25 µg apixaban, and 50 µg edoxaban. Additionally, different enzyme activities were also monitored using a microdosed cocktail approach. The six different azole antifungals were administered in therapeutic doses over a 24 h period, while the microdosed cocktails were administered 1 h after administration of the azole antifungals. RESULTS: Ketoconazole and posaconazole were the strongest perpetrators, showing similar increases as apixaban (area under the concentration-time curve ratio [AUCR] 1.64 and 1.62, respectively) and edoxaban (AUCR 2.08 and 2.1, respectively), whereas ketoconazole increased rivaroxaban 2.32-fold but only increased posaconazole 1.37-fold. All other azole antifungals showed less perpetrator effects on the FXaIs. Cytochrome P450 (CYP) 3A inhibition was confirmed using microdosed midazolam, with ketoconazole also the most potent perpetrator (8.42-fold). CONCLUSION: Drug-drug interactions for three victim drugs of the same drug class (FXaIs) with different clearance mechanisms can be studied using a microdosed cocktail approach. Using members of the azole antifungal drug class as perpetrators, multiple interactions can be studied in one trial, and a more detailed insight into the underlying interaction mechanisms is possible. CLINICAL TRIAL REGISTRATION: EudraCT number: 2017-004453-16.

Pilot study of an occupational healthcare program to assess the SARS-CoV-2 infection and immune status of employees in a large pharmaceutical company.

OBJECTIVE: To safeguard key workers involved in development and production of medicines and ensure business continuity, we developed an occupational healthcare program, performed by our company's occupational healthcare services, to assess the infection and immune status for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This pilot program, conducted at our company facilities, evaluated the suitability of diagnostic tools in our setting for program upscaling. METHODS: We used different marketed in vitro diagnostics (including tests for antibodies against spike protein subunits S1 and S2 and nucleocapsid [N] protein) combined with medical history, symptoms and likelihood of infection. We evaluated the testing strategy over four visits in 141 employees (known positive COVID-19 history, n = 20; unknown status, n = 121) between April and June 2020 at four company locations in Germany. Digital self-monitoring over the pilot program duration was also included. RESULTS: No incident infections were detected. Based on immune status, medical history and likelihood of infection, 10 participants (8.3%) with previously unknown history of COVID-19 were identified to have been infected before entering the program. These participants, who recalled no or mild symptoms in the preceding months, were primarily identified using an assay that detected both S1 and S2 immunoglobulin (Ig) G. The frequency of positive lateral flow assay (LFA) results (IgM or IgG directed against the N-protein) in this cohort was lower compared with participants with a known history of COVID-19 (0‒10.8% vs. 33.8‒75.7%, respectively). CONCLUSIONS: Data from this pilot program suggest that LFA for antibodies may not always reliably detect current, recent or past infections; consequently, these have not been included in our upscaled occupational healthcare program. Regular testing strategies for viral RNA and antibodies directed against different SARS-CoV-2 proteins, combined with hygiene rules and a comprehensive baseline assessment, are recommended to ensure avoidance of infections at workplace as reliably as possible.

Application of Microdosed Intravenous Omeprazole to Determine Hepatic CYP2C19 Activity.

Omeprazole is an established probe drug to assess cytochrome P450 (CYP) 2C19 activity (phenotyping). Because it has nonlinear pharmacokinetics (PK) after oral administration (autoinhibition of metabolism), the true impact of coadministered perpetrators on CYP2C19 substrates might be underestimated after regular doses. We tested the dose linearity of an intravenous omeprazole microdose of 100 µg and compared it with a 20-mg dose in 4 healthy poor metabolizers (PMs) and 6 extensive metabolizers (EMs) of CYP2C19 in the presence and absence of a strong inhibitor (voriconazole). Without voriconazole, omeprazole exposure was dose-proportional irrespective of the genotype, but in PMs geometric mean ratios (GMRs) of AUC0-∞ were 6.6-fold higher and molar metabolic ratios of 5-OH omeprazole/omeprazole approximately 10-fold lower. Voriconazole increased omeprazole exposure in EMs approximately 5-fold (AUC0-4 GMR after 100 µg omeprazole, 4.61; 90% confidence interval [CI], 2.69-7.89; AUC0-4 GMR after 20 mg omeprazole, 5.5; 90%CI, 1.07-1.46), whereas no clinically significant impact on PK in PMs was observed (GMR AUC0-4 after 100 µg omeprazole, 1.29; 90%CI, 0.81-2.04; GMR AUC0-4 after 20 mg omeprazole, 1.25; 90%CI, 1.07-1.46). Linear regression and Bland-Altman analyses revealed excellent agreement between AUC0-∞ and AUC0-4 of omeprazole (r2 = 0.987; bias, 0.35%; 95%CI, -3.197% to 3.89%) and also the molar metabolic ratio, 5-OH omeprazole/omeprazole (r2 = 0.987; bias, -3.939; 95%CI, -9.06% to -1.18%), suggesting that an abbreviated sampling protocol can be used for intravenous CYP2C19 phenotyping and drug interaction studies. In conclusion, the PK of intravenous omeprazole microdoses closely reflects the changes observed with regular omeprazole doses; however, to avoid autoinhibition of probe drugs, microdosing appears to be the favorable technique.

Substantial Impairment of Voriconazole Clearance by High-Dose Meropenem in a Patient With Renal Failure.

A critically ill patient with multiple postoperative infections repeatedly required profound voriconazole dose reductions whenever high-dose meropenem was added. Subsequent in vitro assessment confirmed inhibition of cytochrome P450 (CYP) 2C19 and CYP3A4 by meropenem, suggesting that during meropenem treatment, narrow therapeutic index drugs metabolized by these CYPs require close monitoring.