Lamotrigine drug interactions in combination therapy and the influence of therapeutic drug monitoring on clinical outcomes in paediatric patients

Eight new antiepileptic drugs (AEDs) have been approved for use within the United States within the past decade. They are felbamate, gabapentin, lamotrigine, levetiracetam, oxcarbazepine, tiagabine, topiramate, and zonisamide. These afford clinicians with more options to increase efficacy and tolerability in the treatment of patients with epilepsy. Pharmacokinetic properties and drug interactions with other AEDs and other medications taken for comorbidities are individually discussed for each of these new agents. Drug concentrations are not routinely monitored for these newer agents, and there have been few studies designed to investigate their concentration-effect relationships. For most of these medications, the concentrations observed in responders and nonresponders overlap considerably and levels associated with efficacy are often associated with adverse events, complicating the definition of target ranges. Also, epilepsy manifests itself sporadically causing difficulty in clinically monitoring efficacy of medications. Therapeutic drug monitoring provides for the individualization of treatment for these agents, which is important because they demonstrate significant variability in inter- and intraindividual pharmaco-kinetic properties. Therapeutic drug monitoring also allows for identification of noncompliance, drug interactions, and toxicity. Current knowledge of the relationships between efficacy, toxicity, and drug concentrations is discussed.

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P050 Analysis of posaconazole therapeutic drug monitoring in paediatric haematology and oncology patients

Archives of Disease in Childhood ◽

10.1136/archdischild-2019-nppc.59 ◽

2019 ◽

Vol 104 (7) ◽

pp. e2.55-e2 ◽

Cited By ~ 1

Author(s):

Natalie Donald ◽

Ruth Edwards ◽

Alison Thomson

Keyword(s):

Therapeutic Drug Monitoring ◽

Fungal Infection ◽

Broad Spectrum ◽

Drug Monitoring ◽

Therapeutic Drug ◽

Paediatric Cancer ◽

Oncology Patients ◽

Paediatric Haematology ◽

Paediatric Patients ◽

Trough Levels

Posaconazole is a broad spectrum triazole antifungal with activity against a range of invasive fungal pathogens including Candida and Aspergillus species.1 Due to its range of activity it has been shown, by randomised controlled trials, to be superior to fluconazole and itraconazole for prevention of fungal infection in neutropenic patients,2 as well as being cost saving.1 Fungal prophylaxis with posaconazole has become the drug of choice within a paediatric cancer unit due to its broad spectrum of activity however there are significant differences in bioavailability of the suspension and tablet preparations and there is limited data relating to its use in the paediatric population.ObjectiveTo determine if the paediatric cancer unit is undertaking effective dosing and appropriate therapeutic drug monitoring (TDM) of posaconazole in paediatric haematology and oncology patients.MethodsA retrospective analysis of clinical data from 38 paediatric patients treated with posaconazole was undertaken. Patients received either 18–24-mg/kg/day posaconazole suspension in divided doses (maximum 800-mg/day,3 or 6–8-mg/kg/day posaconazole tablets (maximum 300-mg/day). Compliance with this guidance, initial and subsequent levels, efficacy and tolerability were analysed.SettingThe study was undertaken within the XXXX cancer unit; data for patients treated with posaconazole between January 2016 and August 2017 was reviewed.Key findingsThere was good compliance with the dosing advice for liquid and tablet posaconazole with 82% of patients dosed correctly. Due to this, the initial trough level of ≥0.7 mg/L was achieved in 82% of patients within 14 days of treatment initiation; there were no significant differences between formulations. Trough levels were monitored on a monthly basis for 71% of patients but dose adjustments were necessary in 34% of patients. Posaconazole had a good tolerability profile during the study with most side effects resolving on continuation of treatment however one patient had to discontinue the drug due to widespread rash. No patients developed a fungal infection whilst on posaconazole.ConclusionSafe and effective dosing and monitoring of posaconazole suspension and tablet formulations has been undertaken at the XXXX. Trough levels attained the desired target concentration of ≥0.7 mg/L in the majority of patients but dose adjustments were required with both formulations emphasising the need for regular TDM. Posaconazole was well tolerated and clinically effective in preventing fungal infection indicating its appropriateness in this patient group. From this review, a guideline for initiation and appropriate TDM of posaconazole can be developed.ReferencesDranitsaris G, Khoury H. Posaconazole versus fluconazole or itraconazole for prevention of invasive fungal infections in patients undergoing intensive cytotoxic therapy for acute myeloid leukemia or myelodysplasia: a cost effectiveness analysis. Supportive Care in Cancer. 2011; 19(11): 1807–1813.Cornely O, Maertens J, Winston D, et al. Posaconazole vs. Fluconazole or Itraconazole in Patients with Neutropenia. New England Journal of Medicine. 2007; 356(4): 348–359.Bernardo V, Cross S, Crews K, et al. Posaconazole Therapeutic Drug Monitoring in Paediatric Patients and Young Adults with Cancer. The Annals of Pharmacotherapy. 2013; 47: 976–983.

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Vancomycin prophylaxis in paediatric patients following cardiac surgery: a retrospective evaluation of trough levels and associated variables

Interactive CardioVascular and Thoracic Surgery ◽

10.1093/icvts/ivaa162 ◽

2020 ◽

Vol 31 (5) ◽

pp. 667-673

Author(s):

Leonardo Vallesi ◽

Tiziana Fragasso ◽

Simona Benegni ◽

Giulia Insom ◽

Luca Di Chiara ◽

...

Keyword(s):

Therapeutic Drug Monitoring ◽

Drug Monitoring ◽

Therapeutic Drug ◽

Clinical Predictors ◽

Paediatric Patients ◽

Number Of Patients ◽

Vancomycin Trough ◽

Optimal Target ◽

Independent Association ◽

Trough Levels

Abstract OBJECTIVES Therapeutic drug monitoring during vancomycin administration is recommended. However, little information is available in case of paediatric vancomycin prophylaxis. The aim of this study was to analyse vancomycin trough levels on postoperative day (POD) 2 and 3 after paediatric cardio-surgery to assess the clinical predictors and outcomes associated with vancomycin concentrations and to evaluate whether adjustments are effective to target optimal levels. METHODS A retrospective study was conducted in paediatric patients receiving vancomycin prophylaxis after elective cardio-surgery. Adjustments were made if levels between 20 and 30 (halving subsequent dose) or ˃30 mg/l (dose withheld) were found. RESULTS Vancomycin doses of the 100 examined children (3.7–6.4 years) were 12.8 (2.5), 9.4 (5.4) and 9.7 (4.5) mg/kg, on POD1, 2 and 3, respectively (P = 0.0001). The 200 vancomycin trough levels decreased from 16.9 (11.4) on POD2 to 14.6 (8.5) on POD3 (P = 0.003). Overall, 66 troughs were sub-target, 68 reached the optimal target and 66 were supra-target. On POD2 and 3, 32 and 27 dose adjustments were required, leading to a reduced number of patients with supra-target troughs. Neonates showed a higher number of supra-target levels with respect to non-neonatal patients on both POD2 (P = 0.003) and 3 (P = 0.0001). At multivariable regression analysis, vancomycin levels showed independent association with weight and creatinine levels on both POD2 and 3. Vancomycin levels correlated with ventilation days (P = 0.31, P = 0.039), but not with methicillin-resistant Staphylococcus aureus positivity (P = 0.69). CONCLUSIONS Vancomycin prophylaxis in paediatric cardio-surgery requires strict therapeutic drug monitoring and several dosage adjustments. Supra-target troughs are frequent and neonatal age, weight and creatinine levels significantly affect vancomycin concentrations.

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