[Interaction between azole antifugals drugs and tacrolimus in four kidney transplant patients]. / Interaction médicamenteuse entre des antifongiques azolés et le tacrolimus chez quatre greffés rénaux.

Tacrolimus, an immunosuppressor indicated in solid organ transplantation, has a large inter- and intra-individual variability, a narrow therapeutic index and numerous drug interactions. It is metabolized in the enterocytes and the liver by CYP3A4. Association to enzymatic inhibitors like azole antifungals increase its blood levels and may increase its toxicity directly related to an increase of its blood concentration. We describe in this study four cases of drug interaction between tacrolimus and azole antifungals. These patients were renal transplanted in 2009 and treated with tacrolimus. For fungal infections, azole antifungals were added in these cases. Three were treated by fluconazole and one with voriconazole. By the risk of drug interaction occurrence, tacrolimus doses were decreased by two thirds in one case and by the third in the second case. This association leaded to an increase in tacrolimus concentration (1.33 to 2.45 times the initial concentration) in all patients. Side effects observed in our patients were liver toxicity in two cases, an increase in serum creatinin and an hyperglycemia were notified in all patients. An increase in tacrolimus concentration with about 1.33 times was observed in the case receiving fluconazole intravenously at the dose of 100mg one day out of two and with a tacrolimus doses decrease by two thirds. The patient had impaired renal function before fluconazole introduction. This suggests that in the presence of renal function alteration even low doses of fluconazole with an inhibition of only liver CYPA3A4 (without inhibition of intestinal CYP3A4 and P-gp) leads to an increase on tacrolimus concentration and occurrence of adverse effects related to tacrolimus toxicity. With the co-administration of azole antifugals, it is recommended to adjust tacrolimus dosage on the basis of therapeutic tacrolimus blood monitoring in order to maintain tacrolimus concentration in therapeutic range and to avoid adverse toxic effects.

[Auditory hallucinations due to voriconazole: Illustration by plasma monitoring]. / Hallucinations auditives induites par le voriconazole : illustration par le monitorage plasmatique.

Voriconazole is a second-generation azole antifungal that is widely indicated in the treatment of invasive aspergillosis. It is generally well tolerated. It has nevertheless numerous side effects like hepatotoxicity, photosensitivity, skin rashes, and visual disturbances. Hallucinations were also reported as side effects to voriconazole but auditory hallucinations were rarely reported and seem to be related to toxic voriconazole blood levels. We report, herein, a case of auditory hallucination with monitoring of voriconazole plasma concentration during hallucination and after its disappearance. A 38-year-old man was treated with intravenously voriconazole for a pulmonary aspergillosis. Seven days after the initiation of voriconazole, the patient presented a sudden history of auditory hallucination associated to incoherence and temporo-spatial disorientation. Therapeutic drug monitoring of voriconazole showed a plasmatic residual concentration (C0) of 7.5µg/mL (therapeutic interval: 1.4-1.8µg/mL) and a pic concentration (Cmax) of 9.83µg/mL (therapeutic interval: 2.1-4.8µg/ml). Voriconazole was then stopped and, two days later, symptomatology completely disappeared and at the same time levels of voriconazole decreased (C0=0.11µg/mL and Cmax=2.17µg/mL). We concluded in our case that the patient's auditory hallucinations were caused by voriconazole treatment. In fact, the sudden onset of hallucinations was concomitant with high plasmatic voriconazole levels, and since the medication was stopped, an important decrease of voriconazole levels was observed which was associated with a sudden disappearance of the auditory hallucinations.

[Delayed convulsion after lidocaine instillation for bronchoscopy]. / Convulsion tardive après instillation de lidocaïne pour bronchoscopie.

INTRODUCTION: Lidocaine toxicity usually appears rapidly and is directly correlated with plasma concentrations of the drug. CASE REPORT: We report a case of a late neurologic toxicity occurring after instillation of lidocaine during fibre-optic bronchoscopy. A patient with bronchiolitis obliterans underwent a diagnostic bronchoscopy. She received multiples instillations of Xylocaine(®) 2% (lidocaine). Three and a half hours later, she had a tonic-clonic seizure. Seven hours later, this recurred. Lidocaine plasma levels were in the toxic range at the time of the first seizure (18.32µg/mL) with a significant decrease in the concentration noted 24hours later. CONCLUSION: The slow absorption of lidocaine into the blood from the bronchial tree explains the delayed neurologic toxicity. Our observation is a reminder that complications can occur due to high doses of lidocaïne administrated by instillation. Thus, if the recommended dose of lidocaine is exceeded, it is essential to monitor patients closely for a prolonged period, especially those with fibrosing lung disease in order to avoid possible late toxicity.