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Invasive fungal infections cause significant morbidity and mortality after lung transplantation. Fungal prophylaxis following lung transplantation is not standardised, with transplant centres utilising a variety of regimens. Posaconazole is a broad-spectrum antifungal triazole that requires further investigation within the setting of lung transplantation. This prospective, single-centre, observational study explored the pharmacokinetics of posaconazole oral suspension (POS) in the early perioperative period following lung transplantation in 26 patients. Organ recipients were scheduled to receive 400mg POS twice daily for 6 weeks as primary antifungal prophylaxis. Therapeutic drug monitoring (TDM) of serum posaconazole levels was performed in accordance with local clinical protocols. Bronchoalveolar lavage fluid (BALF) was sampled during routine bronchoscopies. Posaconazole levels were measured both in serum and BALF using mass spectrometry. Posaconazole levels were highly variable within lung transplant recipients during the perioperative period and did not achieve 'steady-state'. Serum posaconazole concentrations positively correlated with levels within the BALF (r=0.5527; P=0.0105). Of the 26 patients, 10 failed to complete the study for multiple reasons and so the trial was terminated early. Unlike study findings in stable recipients, serum posaconazole levels rarely achieved steady-state in the perioperative period; however, they do reflect the concentrations within the airways of newly transplanted lungs. The role of POS as primary prophylaxis in the perioperative period is uncertain, but if used TDM may be helpful for determining attainment of therapeutic levels.

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Milrinone is a bipyridine phosphodiesterase inhibitor with positive inotropic and vasodilatory effects. As interest in longer term use of intravenous therapy increases, it becomes essential to monitor its plasma concentration owing to a narrow therapeutic range, an increased half-life in renal failure and toxicity associated with high levels. A high-performance liquid chromatography (HPLC) method with mass (MS) detection using a triple quadrupole mass spectrometer is presented. The method was compared with the UV/HPLC method and validated according to current international guidelines. Coefficients of variation of less than 7.5% were obtained across the therapeutic range and 18.3% at 2.4 ng/mL, the lower limit of quantitation. Plasma from 13 cardiac surgery patients receiving standard intravenous doses of milrinone were measured. Eight patients achieved therapeutic milrinone levels within 3-4 h post start of infusion, one was borderline sub-therapeutic and four patients achieved levels that were above the upper limit of the therapeutic range and potentially toxic. This method offers high sensitivity, is rapid, easy to use and requires minimal amount of sample. We believe this method could become the reference procedure for clinical monitoring of milrinone and help to improve the safety of the use of this drug in patients with cardiac failure.

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Calcineurin inhibitors (CNIs) have become the cornerstone of immunosuppressive regimens following heart transplantation, but their use is associated with nephrotoxicity. We evaluated a CNI elimination protocol in 14 patients with renal impairment at 48.3 +/- 36.0 months after heart transplantation. The mean serum creatinine was 321 +/- 107 micromol/L; cyclosporine (n=13) or tacrolimus (n=1) was discontinued with sirolimus commenced immediately, initially aiming for a target trough level of 16 (12 to 20) ng/mL. If patients were not receiving mycophenolate (MMF) this was initiated at 1 g bid. The transfer period was covered with a tapering course of corticosteroids. In addition to monitoring clinical status, hematology, biochemistry, and sirolimus levels, graft function was assessed by echocardiography, ECG, and, where indicated, endomyocardial biopsy. Renal function improved in 12 patients (with 6 having a greater than 40% decrease in serum creatinine), remained unchanged in 1, and deteriorated in 1. Two patients who were converted at 15 and 139 months after transplantation experienced grade 3A rejection. One patient experienced a fall in ejection fraction without histologic evidence of rejection. Sirolimus was discontinued in three patients because of side effects: bone marrow suppression, presumed lymphocytic pneumonitis, and generalized acneform rash complicated by an axillary abcess; 50% of patients continue on sirolimus. In conclusion, withdrawal of CNIs after heart transplantation resulted in an improvement in renal function in most patients: 43% experienced a substantial improvement. CNI elimination protocols need to be refined to reduce the risk of breakthrough rejection and to minimize side effects while protecting renal function after heart transplantation.

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Pharmacokinetic profiles were obtained for 16 heart or lung recipients following the administration of identical doses of cyclosporin as oral solution and capsules on consecutive days. A comparison of pharmacokinetic parameters (AUC, Cmax, Cmin and tmax) showed that there were no significant differences between the two formulations except for the tmax, which was significantly longer for the capsules. The mean variation in day-to-day trough levels produced by the two different forms was 25.6%. A retrospective study was carried out of consecutive cyclosporin levels in patients at steady state on oral solution. The mean variation in day-to-day trough levels was 32.3%. This was not significantly different from the variation in consecutive trough levels seen in the oral solution/capsule comparison. This study shows that cyclosporin capsules can be substituted for oral solution without causing acute changes in cyclosporin blood levels, and that the pharmacokinetics of the two formulations are similar.

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Cyclosporin (CsA) is currently the main immunosuppressive agent used in organ transplantation with considerable improvement in graft survival. Oral CsA solution is highly lipophilic, and its bioavailability may be reduced in cystic fibrosis (CF) heart-lung transplant recipients with pancreatic, gastrointestinal, and hepatic insufficiency. The bioavailability of oral CsA solution in 7 CF transplant recipients (5 male and 2 female with a mean age of 27 years and a mean weight of 49 kg) and 3 non-CF heart-lung recipients (1 male and 2 female with a mean age of 41 years and a mean weight of 60 kg) was studied. Following intravenous CsA administration, the kinetic curves were similar with no significant difference in the volume of distribution and clearance of CsA demonstrated between the CF and non-CF groups. The mean daily dose of oral CsA in 7 CF subjects (23.3 mg.kg-1) was significantly higher than the 3 non-CF heart-lung recipients (4.8 mg.kg-1). The mean maximum blood concentration of CsA for the oral dose was 776 ng.ml-1 for the 7 CF subjects, which was comparable with the mean peak values of 789 ng.ml-1 for the 3 non-CF control subjects. Poor enteral absorption of CsA probably accounts for the significantly lower mean bioavailability in the 7 CF subjects (14.9%) compared with the 3 non-CF control subjects (39.4%). The effects on the bioavailability of oral CsA solution by pancreatic enzymes (Creon) and histamine-2 antagonist (ranitidine) were also evaluated in the 7 CF subjects. No significant difference was demonstrated.

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The influence of continuous immunosuppression on the immune system of 2 neonates born to heart-lung transplant recipients was analyzed. T cells, T cell subpopulations, B cells and cyclosporine levels were measured in maternal and cord blood at the time of delivery. Cyclosporine, both parent compound, and metabolites were found in cord blood but in lower amounts than that in the mother. This discrepancy was more pronounced for parent compound than metabolites. Infants born to immunosuppressed mothers had more T and B cells than the mother and had similar numbers of T and B cells to that found in cord blood from 10 babies born to nonimmunosuppressed mothers. One infant had fewer activated T cells and a higher CD4/CD8 ratio due to increased numbers of CD4 cells than normal. In conclusion, neither of these babies had a lymphocyte profile suggestive of chronic immunosuppression.

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