PRIMARY ADRENAL INSUFFICIENCY SECONDARY TO CHRONIC POSACONAZOLE USE

Objective

Posaconazole (PSO) is commonly used in the treatment of invasive fungal infections. PSO-induced primary adrenal insufficiency (PAI) is rare, and we present what we think to be the third case report of its incidence. We want to bring awareness to this rare but significant side effect that can impact management and monitoring of patients on this medication.

Methods

After clinical assessment, the patient was evaluated with diagnostic studies including measurements of cortisol, adrenocorticotropic hormone, renin activity, and aldosterone levels. Imaging studies such as abdominal computed tomography were also performed.

Results

A 65-year-old man with a history of hemophagocytic lymphohistiocytosis on a dexamethasone taper, complicated with mucormycosis on PSO presented to the emergency department with weakness, fatigue, decreased appetite, orthostatic hypotension, low morning cortisol (0.4 μg/dL), low adrenocorticotropic hormone (3.4 pg/mL), elevated plasma renin (16.7 ng/mL/hour), and low-normal aldosterone (1.7 ng/dL). Abdominal computed tomography imaging revealed bilaterally intact adrenal glands. A diagnosis of PSO-induced PAI was made. Fludrocortisone was initiated in addition to glucocorticoids with improvement of fatigue, appetite, blood pressure, and normalization of sodium and potassium. A month after discontinuing PSO, steroids and fludrocortisone were discontinued with measured morning cortisol of 13 μg/dL and an adrenocorticotropic hormone level of 53.9 pg/mL, both normal.

Conclusion

Available data suggest that the adverse effect profile of PSO is more favorable than other triazoles. However, our case is the third report suggesting that PAI may be an underrecognized side effect. Awareness of this complication is particularly important in patients with severe or resistant fungal infections.

Posaconazole Plasma Concentrations on Days Three to Five Predict Steady-State Levels

Low posaconazole plasma concentrations (PPCs) have been associated with breakthrough invasive fungal infections. We assessed the correlation between pre-steady-state PPCs (obtained between days 3 and 5) and PPCs obtained during steady state in 48 patients with underlying hematological malignancies receiving posaconazole oral-solution prophylaxis. Pre-steady-state PPCs correlated significantly with PPCs obtained at steady state (Spearman r = 0.754; P < 0.001). Receiver operating characteristic (ROC) curve analysis of pre-steady-state PPCs revealed an area under the curve (AUC) of 0.884 (95% confidence interval [CI], 0.790 to 0.977) for predicting satisfactory PPCs at steady state.

Antifungal prophylaxis with posaconazole in patients with acute myeloid leukemia: dose intensification coupled with avoidance of proton pump inhibitors is beneficial in shortening time to effective concentrations

This study aimed to assess the influence of dose frequency and the presence or absence of cotreatment with proton pump inhibitors (PPIs) on the time to a target trough concentration (Cmin) of >700 ng/ml with posaconazole in the first 8 days of antifungal prophylaxis in hematological patients. This was a retrospective, observational study performed with 42 adult patients with acute myeloid leukemia who underwent posaconazole prophylaxis with 200 mg every 8 h (q8h) or 200 mg q6h after receiving induction chemotherapy and who had at least three subsequent therapeutic drug monitoring assessments during the first 8 days of treatment. The cohort was split into four groups (group 1, 200 mg q8h without PPI; group 2, 200 mg q8h with PPI; group 3, 200 mg q6h without PPI; group 4, 200 mg q6h with PPI). Rapid attainment of the target Cmin was obtained only in group 3 (P < 0.01) (median Cmin on day 4 of 935.5 ng/ml [interquartile range, 760.0 to 1,270.0 ng/ml] in group 3, versus 567.0 ng/ml [346 to 906 ng/ml] in group 1, 420.0 ng/ml [326.2 to 527.2 ng/ml] in group 2, and 514.0 ng/ml [403.7 to 564.7 ng/ml] in group 4). A linear accumulation of posaconazole over time was observed among patients in groups 1 and 3, regardless of the total daily dosage, differently from what occurred among those receiving PPI cotreatment (groups 2 and 4). Dose intensification (200 mg q6h) coupled with avoidance of PPI coadministration may represent a very powerful strategy to rapidly achieve effective concentrations with posaconazole in neutropenic hematological patients.

Future directions in mucormycosis research

Mucormycosis has emerged as an important opportunistic infection, especially in severely immunosuppressed hosts. The evolving epidemiology, immunopathogenesis, molecular virulence studies, early diagnosis, and pitfalls in designing clinical studies of mucormycosis are discussed in this article.

Posaconazole plasma concentrations and invasive mould infections in patients with haematological malignancies

Posaconazole (PCZ) is a triazole antifungal agent that has broad activity against pathogenic fungi and is increasingly used for prophylaxis and treatment of invasive mould infections (IMIs). PCZ is only available as an oral formulation, with varying absorption from the gastrointestinal tract. However, reports correlating PCZ plasma concentrations (PPCs) with breakthrough IMIs are rare. In this study, PPCs were analysed in a prospective, observational, single-centre study and the correlation of PPCs with breakthrough IMIs in patients with haematological malignancies was evaluated. Risk factors associated with low PPCs were further evaluated. A total of 109 PPCs were measured in 34 cases receiving PCZ prophylaxis (n=31) or treatment (n=3). Levels below the target of 0.5 μg/mL were detected in 24 (71%) of the 34 cases; in 15 (63%) of these 24 cases concentrations were found to be <0.20 μg/mL. Three patients receiving PCZ prophylaxis met the criteria of breakthrough infection. Notably, prior to development of IMI, PPCs were below the target in all three individuals. Associated risk factors for insufficient PPCs varied from previous reports. In conclusion, these data demonstrate that therapeutic drug monitoring of PCZ is mandatory in all patients with haematological malignancies as low PPCs are common and may be associated with development of IMIs.

Melanized fungi in human disease

Melanized or dematiaceous fungi are associated with a wide variety of infectious syndromes, including chromoblastomycosis, mycetoma, and phaeohyphomycosis. [corrected]. Many are soil organisms and are generally distributed worldwide, though certain species appear to have restricted geographic ranges. Though they are uncommon causes of disease, melanized fungi have been increasingly recognized as important pathogens, with most reports occurring in the past 20 years. The spectrum of diseases with which they are associated has also broadened and includes allergic disease, superficial and deep local infections, pneumonia, brain abscess, and disseminated infection. For some infections in immunocompetent individuals, such as allergic fungal sinusitis and brain abscess, they are among the most common etiologic fungi. Melanin is a likely virulence factor for these fungi. Diagnosis relies on careful microscopic and pathological examination, as well as clinical assessment of the patient, as these fungi are often considered contaminants. Therapy varies depending upon the clinical syndrome. Local infection may be cured with excision alone, while systemic disease is often refractory to therapy. Triazoles such as voriconazole, posaconazole, and itraconazole have the most consistent in vitro activity. Further studies are needed to better understand the pathogenesis and optimal treatment of these uncommon infections.

Intracellular concentrations of posaconazole in different compartments of peripheral blood

Therapeutic drug monitoring (TDM) of antifungal plasma concentrations is increasingly recommended. However, data on antifungal concentrations in the other compartments of the peripheral blood are limited. Hence, we collected 23 blood samples from 14 patients receiving posaconazole for prophylaxis of fungal infections. These samples were separated by double-discontinuous Ficoll-Hypaque density gradient centrifugation. The intracellular posaconazole concentrations of the obtained cells, i.e., the peripheral blood mononuclear cells (PBMCs), polymorphonuclear leukocytes (PMNs), and red blood cells (RBCs), were determined by liquid chromatography-tandem mass spectrometry. The intracellular concentrations of the PBMCs and PMNs were significantly higher than those of surrounding media (P < 0.001). The ratios between the intracellular and extracellular concentrations (C/E) were 22.5 +/- 21.2, 7.66 +/- 6.50, and 0.09 +/- 0.05 for the PBMCs, PMNs, and RBCs, respectively. Posaconazole reaches high concentrations within human PBMCs and PMNs and is, to a lesser extent, present in RBCs. The high intracellular concentrations might contribute to posaconazole efficacy and distribution.

Synthesis of a highly water-soluble derivative of amphotericin B with attenuated proinflammatory activity

Amphotericin B (AmB), a well-known polyene antifungal agent, displays a marked tendency to self-associate and, as a consequence, exhibits very poor solubility in water. The therapeutic index of AmB is low and is associated with significant dose-related nephrotoxicity, as well as acute, infusion-related febrile reactions. Reports in the literature indicate that the toxicity of AmB may be related to the physical state of the drug. Reaction of AmB in dimethylformamide with bis(dimethylaminopropyl)carbodiimide yielded an unexpected N-alkylguanidine/N-acylurea bis-adduct of AmB which was highly water-soluble. The absorption spectrum of the AmB derivative in water indicated excellent monomerization, and the antifungal activities of reference AmB and its water-soluble derivative against Candida albicans were found to be virtually identical. Furthermore, the water-soluble adduct is significantly less active in engaging TLR4, which would suggest that the adduct may be less proinflammatory.