Pharmacokinetics of once and twice daily dosing of intravenous tobramycin in paediatric patients with cystic fibrosis.

The optimal dosing of intravenous tobramycin for treatment of pulmonary exacerbations in paediatric cystic fibrosis (CF) patients has not been completely delineated. We performed a retrospective study evaluating the pharmacokinetics and pharmacodynamics of once daily dosing (ODD) of IV tobramycin compared to twice daily dosing (TDD). Fifty-nine and 44 patients were included in the ODD and TDD groups, respectively. Once daily dosing achieved higher Cmax as compared to TDD (29.5 ± 11.0 vs 19.0 ± 4.9, P < 0.001), lower 24 hour AUC (92.8 ± 28.7 vs 128.5 ± 34.6, P < 0.001), and greater time that drug concentration was below the minimum inhibitory concentration (MIC) (13.4 ± 1.7 vs 3.9 ± 3.1 hour, P < 0.001). Twice daily dosing failed to achieve goal Cmax:MIC for MICs >1.0 mg/l. Twice daily dosing may be a viable alternative to ODD in treating organisms with MICs ≤ 1.0 mg/l; however, with MICs >1.0 mg/l, ODD is likely necessary to achieve goal Cmax:MIC ratios.

Aprepitant and fosaprepitant use in children and adolescents at an academic medical center.

OBJECTIVE: To describe the use of aprepitant and fosaprepitant, a neurokinin 1 (NK-1) receptor inhibitor, in children and adolescents at a large academic medical center, for the prevention and management of chemotherapy-induced nausea and vomiting (CINV). METHODS: A retrospective chart review was conducted using an electronic medical record system to evaluate the use of aprepitant and fosaprepitant in all pediatric patients that were discharged from a single academic medical center between February 25, 2009 and May 25, 2012. RESULTS: Twenty-six patients were included in this review and received a total of 287 doses over the span of 114 cycles. Mean age was 10.1 years, with a range of 11 months to 17 years old. In 16 of 26 patients, aprepitant was used as the primary prophylaxis. Of those patients who received primary prophylaxis, 6 of 16 received it for highly emetogenic chemotherapy, and 10 of 16 received it for moderately emetogenic chemotherapy. Intravenous fosaprepitant was used in 7 of 26 patients, ages 13 to 17 (median 14) years old. No adverse effects attributable to aprepitant were reported. CONCLUSIONS: Use of aprepitant and fosaprepitant in pediatric patients appeared to be well tolerated. No currently published reports data using aprepitant in a patient younger than 32 months old, whereas we reported its use in patients as young as 11 months old.

Safety and efficacy of aprepitant for chemotherapy-induced nausea and vomiting in pediatric patients: a prospective, observational study.

Pediatric patients between the ages of 12 months and 17 years with a confirmed malignancy who were scheduled to receive aprepitant as part of triple therapy antiemetic prophylaxis for a cycle of moderately- or highly emetogenic chemotherapy were eligible for enrollment. Patients were evaluated for the incidence of nausea, episodes of emesis, interference with activities of daily living (ADLs), and appetite through utilization of a patient survey. Eleven patients were enrolled for a total of 20 patient encounters, mean age 9.55 ± 4.85 (range, 12 months-17 years). Aprepitant was well-tolerated and complete response (CR) rate was 38.9%.

Erythematous rash following romiplostim administration in a patient with autoimmune lymphoproliferative syndrome.

OBJECTIVE: To report a case of erythematous rash induced by romiplostim administration in a patient with autoimmune lymphoproliferative syndrome (ALPS). CASE SUMMARY: A 19-year-old female with ALPS-related thrombocytopenia (platelet count 4 × 10(3)/µL) successfully treated with romiplostim 500 µg weekly for 9 months presented with a grade 3 maculopapular rash. Symptoms on presentation included purpuric, erythematous pustules confined to the trunk following romiplostim administration the previous day. A punch biopsy of skin from the patient's right lower abdomen revealed perivascular chronic inflammation with numerous eosinophils consistent with drug reaction. The patient had received romiplostim 500 µg weekly with no other reports of rash until this time. Romiplostim was discontinued, the patient was monitored, and the rash resolved within 1 week. Romiplostim was then restarted at 200 µg weekly. The patient has achieved platelet normalization at a current romiplostim dose of 250 µg weekly with no further adverse reactions. DISCUSSION: ALPS is a rare autoimmune disorder with approximately 500 known cases worldwide. Pharmacotherapy for ALPS patients generally targets autoimmune cytopenias associated with the disorder. When standard therapies for ALPS-related cytopenias fail, clinicians are often forced to consider novel treatment options. Our patient had ALPS-related thrombocytopenia that was treated with romiplostim, which resulted in grade 3 maculopapular rash after almost 1 year of treatment. The likelihood that this patient's erythematous rash was due to romiplostim administration was determined to be possible based on the Naranjo probability scale. The reaction was reported to the drug manufacturer and to the Food and Drug Administration's MedWatch program. CONCLUSIONS: This is the first documented case, to our knowledge, of severe maculopapular rash occurring less than 24 hours after romiplostim administration for treatment of ALPS-related chronic thrombocytopenia. Rash has been reported as an adverse event of romiplostim therapy at higher doses (750 µg), but not at a dose of 500 µg. This report also describes successful rechallenge of romiplostim after resolution of the rash.

CoMFA analysis of tgDHFR and rlDHFR based on antifolates with 6-5 fused ring system using the all-orientation search (AOS) routine and a modified cross-validated r(2)-guided region selection (q(2)-GRS) routine and its initial application.

We report the development of CoMFA analysis models that correlate the 3D chemical structures of 80 compounds with 6-5 fused ring system synthesized in our laboratory and their inhibitory potencies against tgDHFR and rlDHFR. In addition to conventional CoMFA analysis, we used two routines available in the literature aimed at the optimization of CoMFA: all-orientation search (AOS) and cross-validated r(2)-guided region selection (q(2)-GRS) to further optimize the models. During this process, we identified a problem associated with q(2)-GRS routine and modified using two strategies. Thus, for the inhibitory activity against each enzyme (tgDHFR and rlDHFR), five CoMFA models were developed using the conventional CoMFA, AOS optimized CoMFA, the original q(2)-GRS optimized CoMFA and the modified q(2)-GRS optimized CoMFA using the first and the second strategy. In this study, we demonstrate that the modified q(2)-GRS routines are superior to the original routine. On the basis of the steric contour maps of the models, we designed four new compounds in the 2,4-diamino-5-methyl-6-phenylsulfanyl-substituted pyrrolo[2,3-d]pyrimidine series. As predicted, the new compounds were potent and selective inhibitors of tgDHFR. One of them, 2,4-diamino-5-methyl-6-(2',6'-dimethylphenylthio)pyrrolo[2,3-d]pyrimidine, is the first 6-5 fused ring system compound with nanomolar tgDHFR inhibitory activity. The HCl salt of this compound was also prepared to increase solubility. Both forms of the drug were tested in vivo in a Toxoplasma gondii infection mouse model. The results indicate that both forms were active with the HCl salt significantly more potent than the free base.