Iatrogenic Cushing's syndrome and osteoporosis due to an interaction between fluticasone and ritonavir

The advent of highly active antiretroviral therapy for HIV infection dramatically changed the landscape of the disease. Ritonavir, a protease inhibitor (PI) frequently used in low doses to 'boost' the concentrations of other PIs, inhibits the cytochrome P450 3A4 isoenzyme, a common metabolic pathway to multiple drugs, so the potential for drug interactions is not negligible. A 39-year-old man with HIV-1 infection, treated with a ritonavir-boosted PI, was started on fluticasone/salmeterol inhaler and intranasal fluticasone, in 2009, in the setting of asthma and allergic rhinitis. In 2013, he presented with 1-year evolution of symptoms suggesting Cushing's syndrome, and was experiencing recurrent falls. A spine CT showed a vertical L3 fracture and thoracolumbar erosions; a bone density scan revealed severe osteoporosis. Hormonal assays were compatible with hypothalamic-pituitary-adrenal axis suppression, and iatrogenic Cushing's syndrome due to ritonavir-fluticasone interaction was considered. Fluticasone was suspended and oral corticosteroid replacement initiated, with a favourable outcome.

[Restraints to anticoagulation prescription in atrial fibrillation and attitude towards the new oral anticoagulants]

INTRODUCTION AND OBJECTIVES

To evaluate the prescription rate of oral anticoagulants in atrial fibrillation, the factors associated with non-prescription, the reasons referred by the physicians for not prescribing anticoagulants including the new generation anticoagulants, and to perform a medium term follow-up assessment.

MATERIALS AND METHODS

Prospective study on consecutive patients with atrial fibrillation with hospital discharge. The CHA2DS2VASc and HASBLED scores, associated comorbidities and medication prescribed before and at discharge were assessed. At discharge, the reason for not prescribing oral anticoagulants and the new oral anticoagulants was indicated by the physician in a questionnaire. Exclusion: absolute contraindication for anticoagulation, CHA2DS2VASc = 1 and valvular disease. Follow-up data were obtained one year after the recruitment of the first patient.

RESULTS

103 candidates for oral anticoagulants were identified (79.6 ± 8.0 years; CHA2DS2VASc 5.8 ± 1.4; HASBLED 2.6 ± 1.0; HASBLED = 3 in 55.3%); the anticoagulants were prescribed in 34.0% of the candidates. The factors associated with non-prescription were, in decreasing order of relevance: previous use of antiplatelet agents, bedridden and/or demented patient, absence of heart failure and number of bleeding risk factors. The reasons referred by physicians for non-prescription were, in decreasing order of frequency: high bleeding risk, small benefit, inability to comply with the treatment regimen and difficulty in monitoring the international normalized ratio (INR). The new anticoagulants were not prescribed and the referred reasons were, in decreasing order of frequency: insufficient information on the drugs, high bleeding risk, high cost and small benefit. At 8.2 ± 2.5 months of follow-up 33.3% of the patients were on anticoagulation and the new anticoagulants had not been prescribed.

CONCLUSIONS

In this sample, the anticoagulants prescription rate was low and the factor most associated with non-prescription was the previous use of antiplatelet agents. Bleeding risk was the most referred barrier for prescription, followed by a small recognized benefit. The main referred barriers for new anticoagulants prescription were insufficient information and high bleeding risk. At medium-term follow-up the proportion of patients under anticoagulation was still low and the new anticoagulants had not been prescribed.