Department of Hospital Pharmacy, Haga Teaching Hospital, Els Borst-Eilersplein 275, 2545 AA The Hague, The Netherlands.
Laboratory of clinical pharmacy and toxicology, Apotheek Haagse Ziekenhuizen, Charlotte Jacobslaan 70, 2545 AB The Hague, The Netherlands.
J Antimicrob Chemother. 2023 Jun 1;78(6):1471-1475. doi: 10.1093/jac/dkad107.
Posaconazole is used as prophylaxis of invasive fungal disease in immune-compromised haematological patients with prolonged neutropenia after intensive chemotherapy. During routine therapeutic drug monitoring of posaconazole, we repeatedly observed low posaconazole serum concentrations in patients that were concomitantly treated with flucloxacillin. A possible interaction between flucloxacillin and posaconazole was explored in this case series.
Posaconazole trough serum concentrations during and before/after flucloxacillin treatment were collected from 10 patients.
With a median concentration of 0.5 mg/L (IQR 0.3-0.6), the posaconazole trough serum concentration decreased by 47% during flucloxacillin treatment compared with the concentration before/after flucloxacillin treatment (0.9 mg/L, IQR 0.6-1.3). As a result, the posaconazole target trough concentration of ≥0.7 mg/L was only achieved in five out of nine patients during flucloxacillin treatment.
Careful monitoring of posaconazole serum trough concentrations is recommended when concomitant use of flucloxacillin cannot be avoided.
泊沙康唑被用作免疫功能低下的血液系统恶性肿瘤患者在强化化疗后中性粒细胞减少时间延长时侵袭性真菌感染的预防用药。在泊沙康唑常规治疗药物监测中，我们反复观察到在同时接受氟氯西林治疗的患者中泊沙康唑的血清浓度较低。在本病例系列研究中，我们探讨了氟氯西林和泊沙康唑之间可能存在的相互作用。
收集了 10 例患者在氟氯西林治疗期间和治疗前后的泊沙康唑谷浓度。
氟氯西林治疗期间，泊沙康唑谷浓度中位数为 0.5 mg/L（IQR 0.3-0.6），与氟氯西林治疗前后（0.9 mg/L，IQR 0.6-1.3）相比，降低了 47%。结果，在氟氯西林治疗期间，9 例患者中有 5 例仅达到了泊沙康唑目标谷浓度≥0.7 mg/L。
当无法避免同时使用氟氯西林时，建议密切监测泊沙康唑的血清谷浓度。
