Effects of Miconazole Oral Gel on Blood Concentrations of Tacrolimus and Cyclosporine: A Retrospective Observational Study

Antifungal Drugs TDM: Trends and Update

PURPOSE

The increasing burden of invasive fungal infections results in growing challenges to antifungal (AF) therapeutic drug monitoring (TDM). This review aims to provide an overview of recent advances in AF TDM.

METHODS

We conducted a PubMed search for articles during 2016-2020 using "TDM" or "pharmacokinetics" or "drug-drug-interaction" with "antifungal," consolidated for each AF. Selection was limited to English language articles with human data on drug exposure.

RESULTS

More than 1000 articles matched the search terms. We selected 566 publications. The latest findings tend to confirm previous observations in real-life clinical settings. The pharmacokinetic variability related to special populations is not specific but must be considered. AF benefit-to-risk ratio, drug-drug interaction (DDI) profiles, and minimal inhibitory concentrations for pathogens must be known to manage at-risk situations and patients. Itraconazole has replaced ketoconazole in healthy volunteers DDI studies. Physiologically based pharmacokinetic modeling is widely used to assess metabolic azole DDI. AF prophylactic use was studied more for Aspergillus spp. and Mucorales in oncohematology and solid organ transplantation than for Candida (already studied). Emergence of central nervous system infection and severe infections in immunocompetent individuals both merit special attention. TDM is more challenging for azoles than amphotericin B and echinocandins. Fewer TDM requirements exist for fluconazole and isavuconazole (ISZ); however, ISZ is frequently used in clinical situations in which TDM is recommended. Voriconazole remains the most challenging of the AF, with toxicity limiting high-dose treatments. Moreover, alternative treatments (posaconazole tablets, ISZ) are now available.

CONCLUSIONS

TDM seems to be crucial for curative and/or long-term maintenance treatment in highly variable patients. TDM poses fewer cost issues than the drugs themselves or subsequent treatment issues. The integration of clinical pharmacology into multidisciplinary management is now increasingly seen as a part of patient care.

[Pharmacokinetic drug interaction between miconazole mucoadhesive tablet and tacrolimus: About 3 case-reports in transplant patients]

Loramyc^® is a mucoadhesive tablet of miconazole, indicated for the treatment of oropharyngeal candidiasis in immunocompromised patients. Miconazole, as others azole antifungals, is known for its potent inhibitory properties of cytochromes P450 enzymes and P-glycoprotein (P-gp). Inhibition of cytochromes P450 enzymes and P-gp can produce pharmacokinetic drug interaction. Immunosuppressive agents, such as calcineurin inhibitors (tacrolimus, cyclosporine) are substrates of cytochromes P450 3A4 and P-gp. Nevertheless, the impact of systemic absorption of miconazole mucoadhesive tablet has not been investigated by the laboratory before regulatory approval. No recommendation currently exists in case of co-prescription of Loramyc^® and immunosuppressive agents which are counter-indicated as a matter of principle. Herein, we present 3 cases of transplanted patients, requiring miconazole mucoadhesive tablet, who presented a tacrolimus overdose. These cases illustrate that of therapeutic drug monitoring is feasible in order to prevent the occurrence of overdoses and adverse reactions related.