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European Journal of Clinical Pharmacology 04/2013; · 2.85 Impact Factor
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Clinical Infectious Diseases 04/2013; · 9.15 Impact Factor
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ABSTRACT: Retrospective studies have documented a significant association between linezolid (LNZ) plasma concentrations and drug-related haematological toxicity. However, the safe upper threshold level for LNZ plasma trough concentrations (Cmin values) has not been defined with certainty. A prospective observational study was performed aimed at comparing LNZ Cmin values in patients developing drug-related side effects with those measured in patients not experiencing LNZ toxicity. LNZ Cmin values were measured from the first week after starting therapy and were repeated periodically up to the end of treatment. Fifty patients, for a total of 210 LNZ Cmin evaluations, were considered. All patients (n=9) who developed drug-related haematological toxicity also had significantly higher plasma LNZ Cmin values during the first week of therapy (9.0±6.4mg/L vs. 4.9±3.7mg/L; P<0.01) and thereafter (9.3±5.4mg/L vs. 4.4±3.4mg/L; P<0.01). The significant association between LNZ plasma concentrations and haematological toxicity was also confirmed by multivariate logistic regression analysis including age, serum creatinine and concomitant medications as independent variables. A causal relationship between LNZ concentrations and the risk of developing drug-related haematological toxicity was observed. Accordingly, application of therapeutic drug monitoring may improve the safety outcome of patients receiving LNZ therapy.
International journal of antimicrobial agents 04/2013; · 3.03 Impact Factor
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Journal of Antimicrobial Chemotherapy 01/2013; · 5.07 Impact Factor
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European Journal of Clinical Pharmacology 09/2012; · 2.85 Impact Factor
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Dario Cattaneo,
Sara Baldelli,
Matteo Cerea,
Simona Landonio,
Paola Meraviglia,
Emanuela Simioni,
Valeria Cozzi,
Serena Fucile,
Andrea Gazzaniga,
Emilio Clementi,
Massimo Galli,
Giuliano Rizzardini,
Cristina Gervasoni
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ABSTRACT: The pharmacokinetics of raltegravir (RAL) in HIV patients is characterised by high inter/intra-patient variability. We investigated the potential contribution of the drug pharmaceutical formulation on RAL pharmacokinetics.We firstly compared in vivo the pharmacokinetics of RAL from 67 patients in which the drug was administered by swallowing the intact tablet with those obtained from 13 HIV-infected patients that chewed the RAL tablet due to swallowing difficulties. Subsequently, we evaluated in vitro the dissolution of RAL tablets under different conditions.In the in vivo study we found that patients given RAL by chewing the tablets presented pharmacokinetic profiles characterised by significantly higher RAL absorption compared with patients receiving the drug by swallowing. The in vitro studies showed that when the whole tablets were exposed to an acidic medium the release of RAL was very low, whereas when crushed the profiles presented significantly higher concentrations of RAL. Crushed tablets tested in water or in a pH 6.8 buffer exhibited prompt and complete dissolution of RAL.HIV-infected patients receiving RAL by chewing the tablet showed higher drug absorption and reduced pharmacokinetic variability compared with patients swallowing the intact tablet. This is related to problems in the tablet disintegration and to erratic drug absorption. The amelioration of the RAL pharmaceutical formulation could improve drug pharmacokinetics.
Antimicrobial Agents and Chemotherapy 09/2012; · 4.84 Impact Factor
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ABSTRACT: Oxatomide at therapeutic doses generates occasionally drowsiness in children. When administered at toxic doses, however oxatomide may induce long lasting impaired consciousness. We now report a case of severe long lasting impaired consciousness induced by therapeutic doses of oxatomide occurring in a child affected by acute gastroenteritis. The clinical symptoms, the pharmacogenetic tests of polymorphisms in cytochrome P450 metabolizing enzymes (CYPs) and the clinical and laboratory analyses indicate that the enhanced drug sedative effect is likely due to an acute, yet mild, inflammatory state of the patient. These findings highlight the importance of assessing common, not serious inflammatory states when oxatomide is prescribed in paediatric patients.
Italian Journal of Pediatrics 03/2012; 38(1):11.
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ABSTRACT: Kidney transplantation in pediatric patients has become a successful and routine procedure, with overall 1-year patient and graft survival rates exceeding 95%. These success rates, however, are not maintained in the long-term, as reported 10-year graft survival rates are in the 50-60% range. Further improvement of long-term allograft survival in pediatric transplantation requires specific focus on long term complications such as increased cardiovascular risk and over-immunosuppression, two linked conditions. One approach to avoid inadequate immunosuppression is to more aggressively tailor immunosuppressive treatment based on individual patient needs. This strategy is currently pursued in the pediatric transplant setting by implementation of individualized therapeutic management of drug concentrations and total exposure. In addition, there is increasing evidence that pharmacogenetic testing may equally benefit individualized immunosuppressive therapy through the identification of SNPs and haplotypes predictive of encoding of proteins involved in drug transport, metabolism and response (efficacy/toxicity). The next challenge will be to provide real time web-based access to all patient information including pharmacokinetic, pharmacodynamic and genotyping data as part of a dosing algorithm or decision support tool with the ultimate goal to adaptively predict and control immunosuppressant exposure and response in individual patients to improve long-term outcomes after kidney transplantation.
Pharmacological Research 02/2012; 65(2):163-7. · 4.44 Impact Factor
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AIDS (London, England) 01/2012; 26(3):398-400; author reply 397-8. · 4.91 Impact Factor
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ABSTRACT: Prescription of generic medicines represents an efficacious healthcare cost containment strategy. In some European countries and in the US, generic medicines are largely prescribed. In Italy, generic drugs prescription rate is lower. General Practitioners and Family Pediatricians may be less confident in prescribing generic equivalents instead of "branded" medicines. There are currently no data about Italian Family Pediatricians' perceptions and patterns of use of generic drugs. This is a first nationwide web survey conducted with the aim to evaluate generic medicines knowledge and prescribing habits of Italian Family Pediatricians. 303 Family Pediatricians completed the online questionnaire. 37.2% and 32.6% of them declared to have a sufficient or fairly good knowledge of generic medicines, respectively, and the majority of them believed that efficacy of generic medicines was sufficient (33.6%) or good (45.2%). Nevertheless, Italian Family Pediatricians are still prone to prescribe trade medicines more frequently, since only 13.5% of them declared that more than a half of their patients were treated with generic medicines. Major issues related with generic medicines prescriptions by Italian Family Pediatricians seem to be represented by diffuse scepticism about reliability of bioequivalence tests and safety of switchability from branded to generic equivalents. More information about generic drugs and more research in the field of pediatric pharmacology are needed for increasing generic medicines prescription rate among Italian Family Pediatricians.
Health Policy 01/2012; 104(3):247-52. · 1.51 Impact Factor
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ABSTRACT: Limited studies in healthy volunteers and in HIV-1-infected patients have shown that raltegravir pharmacokinetics are characterized by high inter-patient variability. Only scanty data are, however, available on intra-patient raltegravir variability. The present study was designed to evaluate in parallel the inter- and intra-patient variability of raltegravir pharmacokinetics in HIV-1-infected patients during routine therapeutic drug monitoring (TDM).
Fifteen HIV-infected patients treated with highly active antiretroviral therapy containing 400 mg of raltegravir twice daily were included in the study. Pharmacokinetic evaluations were performed during two consecutive visits. Only patients given raltegravir for at least 1 month and with no changes in antiretroviral and concomitant therapy between the two pharmacokinetic evaluations were considered. Raltegravir plasma concentrations were determined by a validated HPLC method. Blood samples were collected at 0, 1, 2, 3 and 4 h after the morning drug dose. Raltegravir AUC(0-12) was estimated using a recently developed algorithm.
The pharmacokinetic evaluation was repeated after an average of 52 ± 68 days. Raltegravir AUC(0-12) values ranged from 1495 to 49 051 ng · h/mL. The main finding was that intra-patient variability was a large component of the overall variability in raltegravir pharmacokinetics. In some instances the difference between raltegravir AUC(0-4) and AUC(0-12) measured in the same patient during two consecutive evaluations exceeded 110% and 75%, respectively.
The pharmacokinetics of raltegravir in HIV-1-infected subjects are characterized not only by inter-patient variability but also by high intra-patient variability. This condition limits the application of TDM for raltegravir, and might potentially affect patient outcome.
Journal of Antimicrobial Chemotherapy 11/2011; 67(2):460-4. · 5.07 Impact Factor
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ABSTRACT: Stepwise multiple regression analyses were applied to 44 atazanavir pharmacokinetic profiles from 44 HIV-1 infected patients concomitantly treated with raltegravir with the goal of identifying limited sampling strategies for the prediction of drug AUC(0-12) . Atazanavir trough-based equations failed to reliably predict daily drug exposure in patients with low drug bioavailability. Conversely, different algorithms based on few samples and associated with good correlation, acceptable bias and imprecision with the measured atazanavir AUC(0-12) were identified. These models could be used to predict atazanavir exposure for clinic or research purposes.
Fundamental and Clinical Pharmacology 11/2011; · 1.80 Impact Factor
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ABSTRACT: The potential drug-to-drug interaction between darunavir and raltegravir in the setting of HIV infection is a highly debated issue still unresolved. In the present study we have evaluated the pharmacokinetics of darunavir and ritonavir in 53 HIV-1 infected patients with or without concomitant raltegravir administration. The assessment of trough plasma drug concentrations was carried out in all subjects and the potential influence of raltegravir on darunavir and ritonavir disposition, assessed by specific pharmacokinetic evaluations in a subgroup of 25 patients. No significant differences on darunavir and ritonavir plasma trough levels were observed between patients receiving or not raltegravir. Co-administration of raltegravir was, however, associated with a 40% reduction in darunavir C(max) and estimated AUC(0-24), as well a 60% increase in the estimated darunavir clearance compared with values measured in patients not given raltegravir. Notably, this interaction was independent of the dosage of darunavir and not due to effects of raltegravir on the pharmacokinetics of ritonavir. These results should be taken into account when darunavir-based regimens are implemented in the setting of HIV, especially considering that this drug is usually administered at fixed daily dose and no therapeutic drug monitoring is performed in most centres.
Pharmacological Research 09/2011; 65(2):198-203. · 4.44 Impact Factor
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ABSTRACT: A resolutive therapy for muscular dystrophies, a heterogeneous group of genetic diseases leading to muscular degeneration and in the severe forms to death, is still lacking. Since inflammation and defects in nitric oxide generation are recognized key pathogenic events in muscular dystrophy, we have analysed the effects of a derivative of ibuprofen, NCX 320, belonging to the class of cyclooxygenase inhibiting nitric oxide donator (CINOD), in the α-sarcoglycan null mice, a severe mouse model of dystrophy. NCX 320 was administered daily in the diet for 8months starting 1month from weaning. Muscle functional recovery was evaluated by free wheel and treadmill tests at 8months. Serum creatine kinase activity, as well as the number of diaphragm inflammatory infiltrates and necrotic fibres, was measured as indexes of skeletal muscle damage. Muscle regeneration was evaluated in diaphragm and tibialis anterior muscles, measuring the numbers of centronucleated fibres and of myogenic precursor cells. NCX 320 mitigated muscle damage, reducing significantly serum creatine kinase activity, the number of necrotic fibres and inflammatory infiltrates. Moreover, NCX 320 stimulated muscle regeneration increasing significantly the number of myogenic precursor cells and regenerating fibres. All these effects concurred in inducing a significant improvement of muscle function, as assessed by both free wheel and treadmill tests. These results describe the properties of a new compound incorporating nitric oxide donation together with anti-inflammatory properties, showing that it is effective in slowing muscle dystrophy progression long term. Of importance, this new compound deserves specific attention for its potential in the therapy of muscular dystrophy given that ibuprofen is well tolerated in paediatric patients and with a profile of safety that makes it suitable for chronic treatment such as the one required in muscular dystrophies.
Pharmacological Research 05/2011; 64(3):210-7. · 4.44 Impact Factor
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ABSTRACT: Stepwise multiple regression analyses were applied to 50 raltegravir pharmacokinetic profiles from 50 HIV patients with the goal to identify limited sampling strategies for the prediction of drug area under the time-concentration curve (AUC(0-12)). Raltegravir single sampling point-based equations failed to reliably predict daily drug exposure. Conversely, different algorithms based on few samples and associated with good correlation, acceptable bias, and imprecision with the measured raltegravir AUC(0-12) were identified. These models could used to predict raltegravir exposure for clinic or research purposes.
The Journal of Clinical Pharmacology 03/2011; 52(3):440-5. · 2.91 Impact Factor
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AIDS (London, England) 03/2011; 25(7):1012-3; author reply 1011-2. · 4.91 Impact Factor
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ABSTRACT: An HIV-infected patient with very low atazanavir (ATV) plasma trough concentrations despite clinical signs of poor drug tolerability was described. By therapeutic drug monitoring (TDM), the authors found that the patient had an atypical ATV pharmacokinetics characterized by rapid drug absorption followed by very fast drug clearance probably attributable to his genetic background. This case underlines the importance of traditional and pharmacogenetic-based TDM for the individualization of ATV therapy in HIV-1 patients.
Fundamental and Clinical Pharmacology 01/2011; 26(2):204-6. · 1.80 Impact Factor
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ABSTRACT: This article summarizes part of a consensus meeting about mycophenolate (MPA) therapeutic drug monitoring held in Rome under the auspices of The Transplantation Society in November 2008 (Clin J Am Soc Nephrol. 2010;5:341-358). This part of the meeting focused on the clinical pharmacokinetics of MPA and included discussion on how to measure MPA (active drug) exposure and the differences between the currently available formulations. SUMMARY POINTS: Because of variability in the dose-concentration relationship, MPA exposure should be measured and doses should be adjusted accordingly to achieve optimal clinical outcomes. Suggested therapeutic exposures derived for MPA from mycophenolate mofetil (MMF) may differ to those that could be useful for MPA from enteric-coated mycophenolate sodium (EC-MPS), particularly if limited sampling strategies or single concentration, especially trough concentrations, is used, as the concentration-time profiles of MPA from the 2 formulations are quite different. The 2 MPA formulations cannot be considered as bioequivalent. The area under the concentration-time curve (AUC 0-12) is considered the criterion standard for monitoring of MPA, which is a reflection of exposure to the drug over the entire dosing period. If a limited sampling protocol coupled with multilinear regression or Bayesian estimation is used to estimate this parameter, it should be used only for the population in which the model has been developed and should preferably include at least one time point after 4 hours (preferably around 8 or 9 hours after MMF dosing). If a single time point is to be used as a surrogate for an AUC 0-12, trough concentration of MPA may be the most practical but, from a pharmacokinetic standpoint, is not the most informative time point to choose. Because limited sampling strategies to estimate MPA exposure from EC-MPS have not yet been well developed and fully evaluated, nor have accurate Bayesian estimators been reported, AUC 0-12 measurement is still necessary to obtain reliable estimates of MPA exposure in patients treated with EC-MPS. The measurement of MPA trough concentrations should not be used at all for MPA exposure assessment following administration of EC-MPS. Because limited sampling strategies to estimate MPA exposure from EC-MPS have not yet been well developed and fully evaluated, nor have accurate Bayesian estimators been reported, AUC 0-12 measurement is still necessary to obtain reliable estimates of MPA exposure in patients treated with EC-MPS. The measurement of MPA trough concentrations should not be used at all for MPA exposure assessment following administration of EC-MPS. Lower (or higher) than expected total MPA exposure in patients with severe renal impairment may still indicate sufficient free MPA exposure. Mycophenolate free exposure measurement/estimation is likely to be beneficial in patients with severe renal impairment (creatinine clearance b25 mL/min) to guide dosage estimation, especially because renal function changes over time after transplant, while recognizing that robust prospective studies to show the clinical advantage of measuring free MPA exposure are still required. Lower total measured MPA exposure in patients with hypoalbuminemia may still indicate sufficient free MPA exposure. Mycophenolate free concentration measurement and estimation of exposure are likely to be beneficial in patients with a serum albumin less than or equal to 31 g/L to guide interpretation of MPA exposure. A 1.5-g twice-daily starting dose of MMF rather than a 1-g twice-daily starting dose of MMF is more likely to achieve the minimum target MPA exposure in adult transplant recipients receiving concomitant cyclosporine therapy. Because the cyclosporine dose is progressively tapered following transplantation, MPA exposure should be measured repeatedly and MMF should be doses adjusted accordingly to achieve optimal clinical outcome. Mycophenolate exposure should be measured in the first week after transplant, then each week for the first month, each month until month 3, and subsequently every 3 months up to 1 year with appropriate dosage adjustment, as AUC is likely to increase over time. After 1 year, if dosage requirement has stabilized, MPA exposure can be assessed each time the immunosuppressive regimen is changed or a potentially interacting drug is introduced or withdrawn. Assessment of UGT1A9 single nucleotide polymorphisms (-275TNA, -2152CNT, -440CNT, -331TNC) should be considered before transplantation to assist in dosing decisions to achieve optimal MPA exposure immediately after transplant. Consideration of the points summarized above should lead to more effective dosage adjustment based on sound applied pharmacokinetic and pharmacodynamic principles.
Transplantation reviews (Orlando, Fla.) 12/2010; 25(2):47-57.
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European Journal of Clinical Pharmacology 11/2010; 67(4):429-31. · 2.85 Impact Factor
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ABSTRACT: Raltegravir (RAL) is primarily metabolized by uridine diphosphate-glucorunosyl transferase 1A1 (UGT1A1). Atazanavir (ATV), a strong inhibitor of UGT1A1, has been shown to increase plasma concentrations of RAL by approximately 50% in healthy volunteers. However, the extent of this interaction has not been studied in HIV-infected patients. A pharmacokinetic study was performed in 22 HIV-infected adults treated with 400 mg RAL plus 300 mg ATV 300 twice a day. Both drugs showed high pharmacokinetic variability (RAL AUC 0-12 7649 ± 4862 ng*h/mL; ATV AUC 0-12 = 19237 ± 13136 ng*h/mL). Notably, RAL trough concentrations were significantly higher compared with those measured in HIV subjects (n = 24) on RAL plus nucleoside reverse transcriptase inhibitors (506 ± 411 versus 177 ± 262 ng/mL, P < 0.01). A significant correlation was found between RAL and ATV area under the curve (AUC) (r = 0.611, P = 0.005). Notably, patients with ATV AUC 0-12 above the mean or with concentrations exceeding the half maximal inhibitory concentration for UGT1A1 had twofold higher RAL AUCs compared with patients with lower ATV exposure. Coadministration of ATV significantly increased plasma concentrations of RAL, especially in HIV-1-infected patients exposed to high concentrations of the protease inhibitor. This pharmacokinetic drug interaction could be handled by routine measurements of ATV trough concentrations and by the assessment of plasma RAL concentrations 2 to 3 hours after the morning drug intake.
Therapeutic drug monitoring 10/2010; 32(6):782-6. · 2.43 Impact Factor
