Necessity Of Therapeutic Drug Monitoring Research Articles

Ineffectiveness of carbapenems in real-world clinical practice according to therapeutic drug monitoring data and Roszdravnadzor AIS reports

Relevance. The use of carbapenems is associated with significant variability in pharmacokinetics/pharmacodynamics (FC/PD) parameters, particularly in critically ill patients. The combination of variability in these parameters and standardized dosing regimens can lead to irrational dosing, excessively high or low doses, and consequently less effective treatment and resistance. Optimal management of these factors is essential for combating the development of resistance, particularly for reserve antibiotics.The aim of this study was to evaluate the achievement of the target levels of carbapenems (imipenem/cilastatin) in plasma concentrations in patients with burn injury based on therapeutic drug monitoring and to analyze spontaneous reports registered in the AIS Roszdravnadzor database regarding the effectiveness of therapy.Methods. The analysis included patients receiving antibiotic therapy with imipenem/cilastatin in the burn unit for adults at the University Hospital of the Volga Region Research Medical University for burn trauma who were hospitalized from 01.03.2023 to 30.06.2023. The study was conducted without correcting the trade name of imipenem/cilastatin. Therapeutic drug monitoring was performed after the 4th administration of imipenem/cilastatin. Blood was drawn at 3 h (1st sample), 5 h (2nd sample), and 8 h (3rd sample) after infusion in a clotting activator tube. The analysis was performed using a liquid chromatograph "LC-20 Prominance" (Shimadzu, Japan) in reversed-phase mode with a matrix photodiode detector for UV and visible spectra. Data processing was performed using the LCsolution program. Spontaneous reports regarding the use of carbapenems recorded in the AIS of Roszdravnadzor from January 2020 to November 2023 were also analyzed as the object of the study.Results. The results of the study of carbapenems (imipenem/cilastatin) concentration level achievement in the plasma of patients with burn injury showed that the effective imipenem concentration exceeding the MPC value in relation to the isolated Gram-negative pathogen was found only in 1 out of 5 patients included in the study. Two patients showed dynamically changing IPC values during treatment, indicating the necessity of therapeutic drug monitoring, as well as the probability of failure to achieve target concentrations and optimal FC/FD values. In another two patients, imipenem concentrations were insufficient to maintain optimal FC/PD values, indicating that the antimicrobial regimen was ineffective. An analysis of spontaneous reports registered in the AIS of Roszdravnadzor regarding identified cases of the ineffectiveness of carbapenems (imipenem/cilastatin, meropenem) revealed 5,2% of reports regarding meropenem and 1.4% regarding imipenem/cilastatin in the total structure of reports.Conclusion. The implementation of therapeutic drug monitoring procedures can reduce therapy ineffectiveness and antibiotic resistance through personalized antimicrobial dosing.

Target Therapeutic Ranges of Anti-MRSA Drugs, Linezolid, Tedizolid and Daptomycin, and the Necessity of TDM

The target therapeutic ranges of vancomycin, teicoplanin, and arbekacin have been determined, and therapeutic drug monitoring (TDM) is performed in clinical practice. However, TDM is not obligatory for daptomycin, linezolid, or tedizolid. In this study, we examined whether TDM will be necessary for these 3 drugs in the future. There was no significant difference in therapeutic effects on acute bacterial skin and skin structure infection between linezolid and tedizolid by meta-analysis. Concerning the therapeutic effects on pneumonia, the rate of effectiveness after treatment with tedizolid was significantly lower than with linezolid. With respect to safety, the incidences of gastrointestinal adverse events and blood/lymphatic system disorders related to tedizolid were significantly lower than those related to linezolid. Linezolid exhibits potent therapeutic effects on pneumonia, but the appearance of adverse reactions is indicated as a problem. There was a dose-dependent decrease in the platelet count, and the target trough concentration (Ctrough) was estimated to be 4-6 or 2-7 µg/mL in accordance with the patient's condition. The efficacy of linezolid may be obtained while minimizing the appearance of adverse reactions by performing TDM. The target therapeutic range of tedizolid cannot be achieved in immunocompromised or severe patients. Therefore, we concluded that TDM was unnecessary, considering step-down therapy with oral drugs, use in non-severe patients, and high-level safety. Concerning daptomycin, high-dose administration is necessary to achieve an area under the curve (AUC) of ≥666 as an index of efficacy. To secure its safety, Ctrough (<20 µg/mL) monitoring is important. Therefore, TDM is necessary.

Therapeutic drug monitoring of intravenous busulfan in Thai children undergoing hematopoietic stem cell transplantation: A pilot study

Busulfan (Bu) is commonly used in myeloablative conditioning regimens for children undergoing hematopoietic stem cell transplantation. The standard target area under the concentration-time curve (AUC) of Bu is approximately 900–1500 µM min. In previous studies using five fixed doses (0.8–1.2 mg/kg) for Bu without dose adjustment, 75% patients achieved the target AUC. The aim of this pilot study was to determine the percentage of target AUC for intravenous (IV) Bu in Thai children. IV Bu was administered every 6 h over 16 doses. Blood samples were collected for pharmacokinetic (PK) analysis after the first, ninth, and thirteenth doses of Bu. Seven patients (2–14 years; median 6 years) were diagnosed with thalassemia (n = 4), acute myeloid leukemia (n = 2), and pure red cell aplasia. Three, two, and two patients received Bu at 1.1, 1.2, and 0.8 mg/kg, respectively. The AUC of Bu varied from 292–1714 µM min (median = 804). Nine (42.86%), eleven (52.38%), and one (4.76%) AUC values were within, below, and above the target, respectively. The median (range) Bu clearance was 5.93 (1.91–14.65) mL/min/kg. In this study, 42.86% AUC value achieved the target, which was lower than that in previous studies. Therapeutic drug monitoring (TDM) of Bu should be considered in Thai children receiving five fixed doses of IV Bu, and dose adjustment should be performed as necessary. Further PK studies for Bu with a larger sample size are warranted for confirming the necessity of TDM in every step dose of Bu. (Trial registration numbers; TCTR20190528003)

1537. Multicenter Study with Therapeutic Drug Monitoring (TDM) of Voriconazole (VRCZ) in Japanese Patients

BackgroundTDM of VRCZ might be useful, especially in Asian people because of CYP2C19 genetic polymorphisms. However, limited data are available because of the small sample size.MethodsPatients who received VRCZ and had TDM were reviewed retrospectively at five institutions. Adequate VRCZ dosage was defined as a loading dose of 5–6 ± 0.5 mg/kg twice daily followed by a maintenance dose of 3–4 ± 0.5 mg/kg twice daily. For prophylaxis, the loading dose was left to the physician’s discretion. Optimal timing of TDM was defined as 4–7 days after starting therapy. Patients with adequate dosing and optimal timing of TDM were evaluated for analysis of trough levels (Cmin). Target Cmin was set at 1–5 µg/mL.ResultsThe study included 584 patients (treatment: 402; prophylaxis: 182). TDM was conducted on days 4–7 in 66.5% of patients (>7, 30.2%). A low adequate dosage (44.5%) was observed for treatment mainly because of a low performance of the loading dose (46.8%). Achievement of target Cmin was obtained in 62.7% (>5 µg/mL, 32.2%) in the treatment group and in 67.6% (11.0%) in the prophylaxis group. Seventy-one of 81 (81.7%) patients who required a dose reduction reached target Cmin by the second TDM. In 38 patients whose dose was not altered at oral switching, Cmin was significantly reduced from 2.5 ± 1.6 to 1.2 ± 1.3 μg/mL (P = 0.002), which indicated the necessity of TDM after oral switching. Hepatotoxicity occurred in 4.6% and visual symptoms in 7.9% of patients. Visual symptoms resolved without discontinuation of VRCZ in 73.9% of patients. Because of dosage adjustment based on TDM, high Cmin did not cause hepatotoxicity. However, the incidence of visual symptoms was significantly higher in patients with a high Cmin (12.7% vs. 5.4%, P = 0.002).ConclusionOne-third of Japanese patients who underwent VRCZ treatment with a loading dose showed high Cmin. Occurrence of hepatotoxicity was prevented with alteration of dosage in these patients (AMED, JP18fk0108045).Disclosures All authors: No reported disclosures.

Monitoring of tobramycin serum concentrations in selected critically ill patients receiving selective decontamination of the digestive tract: a retrospective evaluation.

Selective decontamination of the digestive tract (SDD) is a strategy in mechanically ventilated patients to reduce mortality. Treatment consists of enterally administered non-absorbable antibiotics, i.e., tobramycin. However, most intensive care unit (ICU) patients with SDD appear to have detectable tobramycin serum concentrations. The Rijnstate Hospital implemented a protocol for therapeutic drug monitoring (TDM) of tobramycin in patients at risk. The aim of this study was to evaluate the necessity of TDM in these patients and to optimize the current protocol. This retrospective observational study included ICU patients with SDD treatment for ≥ 7days and renal failure. These patients were considered eligible for monitoring of tobramycin. Tobramycin serum concentrations, relevant laboratory parameters (i.e., renal function, lactate), and patient data were extracted from the National Intensive Care Evaluation database and the hospital electronic patient data system. In 23 subjects, a total of 43 tobramycin serum concentrations was determined. The median tobramycin serum concentration was 0.33 (IQR 0.17-0.49) mg/L of which 12 (27.9%) samples had concentrations < 0.2mg/L, 30 (69.8%) had concentrations 0.2-1.0mg/L and 1 (2.3%) had a toxic concentration > 1.0mg/L. In 3 (7.0%) cases, an intervention was conducted based on the tobramycin serum concentration. The majority (83.7%) of samples had detectable tobramycin serum concentrations. Monitoring of tobramycin serum concentrations can be considered necessary in patients at risk. However, the current protocol should be optimized to intercept patients more precise.

Clinical pharmacokinetic and pharmacodynamic analysis of daptomycin and the necessity of high-dose regimen in Japanese adult patients

The objective of this study was to explore the optimal dosage regimen of daptomycin and to determine the necessity and validity of a high-dose regimen from the perspectives of PK/PD parameters using Monte Carlo Simulation (MCS) and therapeutic drug monitoring (TDM) in a Japanese clinical setting. The volume of distribution (0.13 ± 0.012 L/kg) in this study was greater than that in healthy volunteers reported in Japan. The range of half-lives was between 8.9 and 34.9 h, which were gradually prolonged as creatinine clearance decreased. In MCS, the cumulative fractions of response (CFR) of the peak/MIC ≧ 60 and the AUC/MIC ≧ 666 at the 6 mg/kg q 24 h were 72.0% and 78.8% but at the 10 mg/kg q 24 h, the CFRs improved to both 99%. In TDM with 6 mg/kg q 24 h regimen, the patients who reached the peak and AUC target were 40% (2 out of 5 patients), respectively. The intraindividual variability in daptomycin PK may indicate the necessity of TDM and high-dose regimen, such as over 8 mg/kg, may be needed to ensure the effectiveness especially on Japanese patients with normal renal function.

A novel reversed-phase high-performance liquid chromatographic assay for the simultaneous determination of imipenem and meropenem in human plasma and its application in TDM

A rapid and specific reversed-phase high-performance liquid chromatographic (RP-HPLC) assay with UV detection has been developed and validated for the simultaneous determination of imipenem and meropenem in human plasma. The extraction process was performed through protein precipitation method using acetonitrile and dichloromethane, and the recoveries of quality controls (QCs) were > 91.5%. Isocratic elution followed by gradient elution of acetonitrile and water was employed over a C18 analytical column for separation. The detection was performed at 298 nm. This method was accurate and reproducible (coefficient of variation, CV < 8%), allowing quantification of carbapenem at the plasma-level ranges from 0.1 to 100 μg/ml without interference of any of the 30 frequently prescribed drugs. Stabilities of imipenem and meropenem were determined with or without stabilizer solutions at -80°C, -20°C, +4 °C and room temperature 20°C. These two drugs showed higher stability at the low temperatures. Addition of 3-(N-morpholino) propanesulfonic acid (MOPS) might also increase their stability. The results of therapeutic drug monitoring (TDM) in neonates and adults showed high inter- and intra- individual variabilities in the trough concentrations of imipenem and meropenem, thus confirming the importance and necessity of TDM. For neonatal patients, imipenem 20 mg/kg, q12h (40mg/kg/day) failed to produce significant therapeutic effects, and either the dose or the frequency was adjusted to achieve 60mg/kg/day or above to maintain the trough concentration required for the curative effect. The low operational cost and good separation efficiency would help implement this assay for the routine therapeutic drug monitoring of imipenem and meropenem in hospitals.

Linezolid in liver failure: exploring the value of the maximal liver function capacity (LiMAx) test in a pharmacokinetic pilot study

Patients in the intensive care unit frequently require antibiotic treatment. Liver impairment poses substantial challenges for dose selection in these patients. The aim of the present pilot study was to assess the novel maximal liver function capacity (LiMAx test) in comparison with conventional liver function markers as covariates of drug clearance in liver failure using linezolid as a model drug. A total of 28 patients with different degrees of liver failure were recruited. LiMAx test as well as plasma, dialysate and urine sampling were performed under linezolid steady-state therapy (600 mg twice daily). NONMEM® was used for a pharmacometric analysis in which the different clearance routes of linezolid were elucidated. Linezolid pharmacokinetics was highly variable in patients with liver failure. The LiMAx score displayed the strongest association with non-renal clearance (CLnon-renal) [ = 4.46∙(body weight/57.9) 0.75∙(LiMAx/221.5)0.388 L/h], which reduced interindividual variability in CLnon-renal from 46.6% to 33.6%, thereby being superior to other common markers of liver function (international normalised ratio, gamma-glutaryl transferase, bilirubin, thrombocytes, alanine aminotransferase, aspartate aminotransferase). For LiMAx < 100 µg/kg/h, 64% of linezolid trough concentrations were above the recommended trough concentration of 8 mg/L, indicating the necessity of therapeutic drug monitoring in these patients. This is the first pilot application of the LiMAx test in a pharmacokinetic (PK) study demonstrating its potential to explain PK variability in linezolid clearance. Further studies with a larger patient collective and further drugs are highly warranted to guide dosing in patients with severe liver impairment.

The Effects of Fasting and Massive Diarrhea on Absorption of Enteral Vancomycin in Critically Ill Patients: A Retrospective Observational Study.

Although vancomycin (VCM) is not absorbed from healthy intestinal mucosa, elevations in the serum VCM concentrations have been reported in some cases. The aims of this study are to evaluate the necessity of therapeutic drug monitoring (TDM) during enteral VCM administration in critically ill patients. In this retrospective study, we enrolled 19 patients admitted to our intensive care unit who were treated with enteral VCM from December 2006 to January 2014. Clinical factors were compared between two groups: Group E whose serum concentrations were detectable, and Group N whose concentrations were below the detection limit of the VCM assay. Group E comprises 7 patients, and Group N comprises 12 patients. The fasting duration in Group E was significantly longer compared with that in Group N (17 vs. 8 days, p = 0.023). Furthermore, there was a significant correlation between the serum VCM concentrations and the fasting duration (r = 0.79, p < 0.0001), and the amount of diarrhea (r = 0.46, p = 0.046). No difference was observed in the amount of diarrhea at the time of TDM (Group E; 1,850 mL vs. Group N; 210 mL, p = 0.055) and in the Sequential Organ Failure Assessment subscore for the renal system at the time of TDM (Group E; 4.0 vs. Group N; 1.5, p = 0.068). Long durations of fasting and massive diarrhea were associated with elevations in the serum VCM concentrations, which suggested that TDM might be necessary during enteral VCM administration in critically ill patients. UMIN Clinical Trials Registry identifier UMIN000016955.

Individual peculiarities in pharmacokinetics of antiblastomic drugs in healthy volunteers

The data of inter-individual variations in pharmacokinetics of antiblastomic drugs from the group of tyrosine proteinkinase inhibitors (imatinib, gefitinib and nilotinib) and antiblastomic immune modulator lenalidomide in healthy volunteers by meams of HPLC-MS/MS were represented in the article. The concentrations of the drugs studied were measured in the volunteer blood serum. The indeces Cmax (maximal concentration and time reaching), Tmax (time covering maximal concentration measure), AUC0-t (squire under pharmaceutical curve) were processed by trapetias method, Cmax/AUC0-t as well as Kel (elimination constant) and T1/2 (period of semielimination) according to individual signs. The significant individual variability revealed for imatinib, gefitinib and nilotinib in healthy volunteers indicates on necessity of therapeutic drug monitoring in patients treated with them to aim optimal dosing.

Benefits of therapeutic drug monitoring of vancomycin: a systematic review and meta-analysis.

Background and ObjectiveThe necessity of therapeutic drug monitoring (TDM) for vancomycin is controversial. The objective of the current review was to evaluate the available evidence for the necessity of TDM in patients given vancomycin to treat Gram-positive infections.MethodsMedline, Embase, Web of Sciences, the Cochrane Library and two Chinese literature databases (CNKI, CBM) were searched. Randomized controlled studies and observational studies that compared the clinical outcomes of TDM groups vs. non-TDM groups were included. Two reviewers independently extracted the data. The primary outcome was clinical efficacy of therapy. Secondary outcomes included vancomycin associated nephrotoxicity, duration of vancomycin therapy, length of hospital stay, and mortality. Meta-analysis was performed using the Mantel-Haenszel fixed effect method (FEM). Odds ratios (ORs) or weighted mean differences (WMD) with 95% confidence intervals (95%CIs) were calculated for categorical and continuous outcomes, respectively.ResultsOne randomized controlled trial (RCT) and five cohort studies were included in the meta-analysis. Compared with non-TDM groups, TDM groups had significantly higher rates of clinical efficacy (OR = 2.62, 95%CI 1.34–5.11 P = 0.005) and decreased rates of nephrotoxicity (OR = 0.25, 95%CI 0.13–0.48 P<0.0001). Subgroup analyses showed that TDM group had significantly higher rates of clinical efficacy in both cohort studies subgroup (OR = 3.04, 95%CI 1.34–6.90) and in Asian population subgroup (OR = 3.04, 95%CI 1.34–6.90). TDM group had significantly decreased rates of nephrotoxicity in all subgroup. There was no significant difference in duration of vancomycin therapy (WMD = −0.40, 95%CI −2.83–2.02 P = 0.74) or length of stay (WMD = −1.01, 95%CI −7.51-5.49 P = 0.76) between TDM and non-TDM groups. Subgroup analyses showed there were no differences in duration of vancomycin therapy. Only one study reported mortality rates.ConclusionsStudies to date show that TDM significantly increases the rate of clinical efficacy and decreases the rate of nephrotoxicity in patients treated with vancomycin.

Niveau de preuve du suivi thérapeutique pharmacologique de la ceftriaxone

Ceftriaxone is a third generation cephalosporin with an original pharmacokinetics based on a long elimination half-life among cephalosporins, a high protein binding and a dual renal and biliary elimination. Also the pharmacokinetic parameters of ceftriaxone are highly variable in clinical situations such as severe renal insufficiency, liver and renal insufficiency, the elderly, the neonates less than 1 week of age and critically ill patients. In these clinical situations associated or not with high minimal inhibitory concentration (MIC) level, the relationship concentration-clinical outcome based on the ratio between trough plasma concentration and MIC can allow a dose adjustment. Consequently, therapeutic drug monitoring (TDM) of ceftriaxone could be possibly useful in these situations, whereas the necessity of TDM has still to be demonstrated to monitor toxicity.

Pharmacokinetic monitoring is still required for intravenous busulfan in SCT for small children

Busulfan (BU) is an alkylating agent that is used in alter-native conditioning regimen for total body irradiation(TBI) before stem cell transplantation (SCT) especially toreduce its late toxicities such as growth impairment andsecond malignancy. Because its therapeutic window isnarrow and, inter- and intra-patient variability of plasmaexposure is wide in case of conventional oral formulation,therapeutic drug monitoring (TDM) is recommended toavoid severe toxicity or rejection, especially in youngerpatients in which its variability is much more [1, 2]. ByTDM, BU dose should be adjusted so that calculatedconcentration at steady state (Css) or area under the curve(AUC) is in the range of 600–900 ng/ml or 900–1500 mmol min/L. In this context, introduction of intra-venous formulation is expected to resolve these problems.For small children, recommended dose for intravenousformulation has been reported [3, 4]. However, there is arecent report that emphasizes the necessity of TDM even inintravenous formulation [5]. In this background, weinvestigated allogeneic SCT cases with BU regimen in ourinstitute retrospectively.Since 1995, 34 patients received allogeneic hematopoi-etic SCT by using BU regimen in our pediatric section.Former 29 patients received BU orally (four doses per dayfor four consecutive days; p.o.BU group), and latter fivepatients received BU intravenously (2-h infusion every 6 hfor four consecutive days; i.v.BU group).For pharmacokinetic (PK) analysis, blood samples wereobtained 1, 2, 3, 4, and 6 h after medication of BU. Inp.o.BU group, PK analysis were performed in the last 10cases, in which test dose (0.5–0.7 mg/kg) was performed2 weeks before conditioning chemotherapy, and dose wasadjusted according to the result of PK analysis up to themaximal dose of 2 mg/kg/dose (Table 1). PK analysis wasalso performed for the initial dose, and dose was adjustedin fourth day (13th dose) in case calculated Css of BUexceeded the range of 600–900 ng/ml [Only in case 3, dosewas reduced from 1.8 to 1.1 mg/kg/dose.]. In i.v.BU group,BU was administered according to the recommendation [3,4], and blood sample was taken and stored for later PKanalysis except for the last case (case 15). In case 15, testdose was performed, and dose was reduced from 1.0 to0.8 mg/kg/dose. Informed consent was obtained from all ofthe patients or patient’s guardians before conducting thetest dose. Also, we have approval for this procedure fromour IRB.Among 15 cases in which PK analysis was performed(Table 1), graft rejection was observed only in one case(case 5) of p.o.BU group, which was a patient withhemophagocytic lymphohistiocytosis. No hepatic veno-occlusive disease (HVOD) occurred in p.o.BU group, butwas observed in two out of five i.v. cases, in which onecase (case 13) had severe HVOD and died 60 days afterSCT because of hepatic failure. In case 13, the patientreceived first SCT from HLA identical sibling with TBI(12 Gy) and cyclophosphamide (60 mg/kg 9 2 days) reg-imen. After relapse in 3 months, he was treated withHperCVAD plus imatinib chemotherapy [6] and received

Selection of the Optimum Measurement Point to Predict Plasma Concentrations of a Drug. Application to a Kampo formulaiton.

In Therapeutic Drug Monitoring (TDM), does and intervals of administration are adjusted according to the individual patient based on plasma concentrations predicted from one or two measurements of the patient. Such monitoring has been applied to many kinds of drugs and is necessary in the study of Kampo formulations too. In this kind of monitoring, the selection of measurement points is quite important in order to achieve accurate predictions. The purpose of this paper is to propose a Monte Carlo approach to the selection of the optimum measurement point to predict plasma concentrations of a drug. The proposed approach is applied to the data obtained in a clinical phase-one study of a Kampo formulation. The necessity of Therapeutic Drug Monitoring for Kampo formulations is also discussed.

Therapeutic Drug Monitoring of Suramin and Protein Binding

Abstract A liquid chromatographic method of suramin has been used for the determination of the polysulfonated naphtylurea in both plasma and plasma filtrate from prostate cancer patients treated with the drug. The chromatographic system is based on the use of tetrabutylammonium bromide as an ion-pairing agent, while UV detection at 237 nm and 313 nm is applied. The sample pretreatment is a simple deproteination step by an organic solvent. The same counter-ion as used in the phase system is added in order to increase the recovery of the almost complete protein-bound suramin. The minimum detectable concentration in plasma is ca. 20 ng/mL at 237 nm, in plasma filtrate 10 ng/mL at 237 nm. The method was routinely applied in plasma level guided treatment of prostate cancer patients with suramin, as well as in protein binding studies. The data of the study demonstrated the necessity of therapeutic drug monitoring in suramin treatment: development of severe, irreversible toxicity could be prevented owing to time...