Antifungal Dosing in Obesity: A Review of the Literature

Efficacy of Super-Bioavailable Itraconazole and Conventional Itraconazole at Different Dosing Regimens in Glabrous Tinea Infection - A Randomized Clinical Trial

Introduction

Itraconazole follows non-linear pharmacokinetics and hence is recommended once daily, but in real-world practice, is commonly prescribed as twice daily. Hence, this study aimed to evaluate the efficacy and safety of super-bioavailable-itraconazole-130 mg (SB-130) and conventional-itraconazole-200 mg (CITZ-200) once daily compared with conventional-itraconazole-100 mg (CITZ-100) twice daily in glabrous tinea.

Methods

A total of 261 eligible patients were enrolled in this prospective, randomized, clinical study from December-2021 to August-2022 at seven centers in India. Efficacy and safety assessments were done at week-3 and 6, with follow-up at week-10 for relapse. The primary objective was to assess the proportion of patients who achieved complete cure at week-6 following treatment in all itraconazole groups. The secondary outcomes were safety and clinical and mycological cure rates.

Results

Of 261 patients, 240 were included in the analysis. At week-6, 140 patients were completely cured; thus, overall cure rate was 58.33%. Fifty-five patients (69%) in SB-130 while 47/77 (61%) and 38/83 (46%) patients were completely cured in CITZ-200 and CITZ-100 groups respectively (p<0.05; SB-130: CITZ-100, p=0.32; SB-130: CITZ-200, p=0.058; CITZ-200: CITZ-100). There was no statistical difference in the mycological cure rate and area clearance rate between any of the groups (p=0.14); however, a statistically significant difference was noted for OD dosing over BD dosing in achieving clinical cure rates (p<0.05). A total of 13/140 patients (9%) relapsed following complete cure, with no statistically significant difference between any of the groups (p=0.50). All treatments were safe and well-tolerated, with no discontinuation.

Conclusion

In this clinical study, moderate efficacy with all doses of ITZ was reported but was better with OD dosing. Although there was no statistical difference between SB-130 and CITZ-200, SB-130 may be preferred over CITZ-200 owing to the advantage of SB over the conventional ITZ.

Overview of antifungal dosing in invasive candidiasis

In the past, most antifungal therapy dosing recommendations for invasive candidiasis followed a 'one-size fits all' approach with recommendations for lowering maintenance dosages for some antifungals in the setting of renal or hepatic impairment. A growing body of pharmacokinetic/pharmacodynamic research, however now points to a widespread 'silent epidemic' of antifungal underdosing for invasive candidiasis, especially among critically ill patients or special populations who have altered volume of distribution, protein binding and drug clearance. In this review, we explore how current adult dosing recommendations for antifungal therapy in invasive candidiasis have evolved, and special populations where new approaches to dose optimization or therapeutic drug monitoring may be needed, especially in light of increasing antifungal resistance among Candida spp.