Background New oral anticoagulant drugs (NOACs) are glycoprotein-P (gp-P) substrate, a membrane transporter protein and principally they are metabolised by CYP3A4. NOACs administration with antibiotics is not recommended because they are powerful CYP3A4 and gp-P inhibitors. It would lead to a NOACs metabolism reduction, increasing plasma concentration and, consequently, the exposure to the active substance with the risk of bleeding.
Purpose The aim of this study consisted in searching for patients with concomitant NOACs and antifungal therapies, and examining general practitioners’ prescriptions.
Material and methods Prescriptions from an Italian district in 2017, in charge of the Italian national health system, were analysed. The molecules considered were NOACs: Apixaban, Edoxaban, Rivaroxaban, Dabigatran and the antifungal Itraconazole. Data have been extracted from a database S2i-italia and they have been elaborated with Access.
Results In 2017, 7404 patients were treated with NOACs and 2580 patientswith Itraconazole. Thirteen patients had concurrent prescriptions of NOACs and Itraconazole (0.18% of all patients with NOACs prescriptions), with a median age of 72 years (range 43–83 years). The age ≥75 years’ old is a risk factor because NOACs metabolism is slowed down and it is possible that it increases more plasma concentration. The NOACs molecules prescribed concurrently with Itraconazole were: Apixaban for five patients, Dabigatran for four, Rivaroxaban for three and Edoxaban for one. The average number of NOACs packs delivered to a patient was 5.5 (72 in total), the exceptions were the cases of two patients 76 years’ old with 14 and 24 packs prescribed concurrently with acetylsalicylic acid for the whole analysed year, although they should have been avoided in the case of increased haemorrhagic risk.
Conclusion In 2017, 1.72% of examined patients had NOACs and/or Itraconazole prescriptions, but only 0.18% of them had concurrent therapies, even if it was contraindicated because of the increase in bleeding risk. The advanced average age caused slowing of the metabolism: the frequent polypharmacy with the possibility of drug interaction increased the bleeding risk. It is appropriate to focus on each case and evaluate dose reduction, and make a therapeutic reconciliation, especially in elderly patients in polytherapy.
References and/or acknowledgements ‘Progetto Farmamico: Interazioni TAO, AVK, NAO, Guida Medica’.
No conflict of interest.