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At least 361 records · Page 20Linked to original sources

PubMed2001

Motion adaptive x-ray therapy: a feasibility study.

Intrafraction motion caused by breathing requires increased treatment margins for chest and abdominal radiotherapy and may lead to 'motion artefacts' in dose distributions during intensity modulated radiotherapy (IMRT). Technologies such as gated radiotherapy may significantly increase the treatment time, while breath-hold techniques may be poorly tolerated by pulmonarily compromised patients. A solution that allows reduced margins and dose distribution artefacts, without compromising delivery time, is to synchronously follow the target motion by adapting the x-ray beam using a dynamic multileaf collimator (MLC), i.e. motion adaptive x-ray therapy, or MAX-T for short. Though the target is moving with time, in the MAX-T beam view the target is static. The MAX-T method superimposes the target motion due to respiration onto the beam originally planned for delivery. Thus during beam delivery the beam is dynamically changing position with respect to the isocentre using a dynamic MLC, the leaf positions of which are dependent upon the target position. Synchronization of the MLC motion and target motion occurs using respiration gated radiotherapy equipment. The concept and feasibility of MAX-T and the capability of the treatment machine to deliver such a treatment were investigated by performing measurements for uniform and IMRT fields using a mechanical sinusoidal oscillator to simulate target motion. Target dose measurements obtained using MAX-T for a moving target were found to be equivalent to those delivered to a static target by a static beam.

Feasibility Studies↗

PubMed2006

Inverse planning--a comparative intersystem and interpatient constraint study.

PURPOSE: To compare commercial treatment-planning systems (TPS) for inverse planning (IP) and to assess constraint variations for specific IMRT indications. MATERIAL AND METHODS: For IP, OTP, XiO and BrainSCAN were used and step-and-shoot intensity-modulated radiotherapy (IMRT) delivery was assumed. Based on identical constraints, IP was performed for a prostate, head and neck, brain, and gynecologic case. IMRT plans were compared in terms of conformity/homogeneity, dose-volume histograms (DVHs), and delivery efficiency. For ten patients each of a class of indications, constraint variations were evaluated. RESULTS: IMRT plans were comparable concerning minimum target dose, homogeneity, conformity, and maximum doses to organs at risk. Larger differences were seen in dose gradients outside the target, monitor units, and segment number. Using help structures proved efficient to shape isodoses and to reduce segmentation workload. For IMRT class solutions, IP constraint variations depended on anatomic site. CONCLUSION: IP systems requiring doses as input and having objective functions based on physical parameters had a very similar performance. Constraint templates can be established for a class of IMRT indications.

Brain Neoplasms↗

PubMed2004

Can photon IMRT be improved by combination with mixed electron and photon techniques?

Conformal radiotherapy or intensity modulated radiotherapy (IMRT) commonly leads to a large integral dose in the patient. Electrons would reduce the integral dose but are not suitable for treating deep-seated tumours, owing to their limited penetration. By combining electron and photon beams, the dose distributions may be improved. In this study, the possibility is explored of using a mixture of electron and photon beams for a deep-seated target volume in the head and neck region. Treatment plans were made for five simulated head and neck cancer cases. Mixed electron and photon beam plans (MB) were constructed using a manual iterative procedure. Photon IMRT plans were optimized automatically. Both electron and photon beams were collimated by a computer controlled multi-leaf collimator (MLC). Both methods were able to produce clinically acceptable plans. Criteria for the target dose were met similarly by both as were the criteria for critical organs. The integral dose outside the planning target volume (PTV) showed a tendency to be lower with MB plans compared with photon IMRT plans. A mixed electron and photon technique has the potential to treat deep-seated tumours. It is reasonable to expect that if computerized optimization tools were coupled with the mixed electron and photon beam technique, treatment goals would be more readily achieved than if using solely pure photon IMRT.

Combined Modality Therapy↗

PubMed2004

The influence of lateral electronic disequilibrium on the radiation treatment planning for lung cancer irradiation.

Using higher energy photons can obtain better target dose uniformity and skin sparing for treating deep lesions, but the effect of lacking lateral scattering in the low-density lung may degrade the target coverage. To analyze the influence of lateral electronic disequilibrium on the radiation treatment planning for lung cancer, three dimension conformal treatment (3D-CRT) plans of using 6 MV and 18 MV X-ray respectively for a lung cancer case have been worked out by using pencil beam algorithm and collapsed cone algorithm provided by Helax-TMS treatment planning system for the same radiation field arrangement for both energies. Dose volume histogram (DVH) in target and organs at risk (OARs) are used for comparison of different plans. The study shows that using pencil beam algorithm, the target DVH are similar for 6 MV and 18 MV plan. However, using collapsed cone algorithm that can make account of lateral electron scattering, the target is underdosed. The change is even more pronounced for 18 MV plan. The doses for lung and spinal cord are similar for these two energies and two algorithms. Therefore, for lung cancer, dose calculation algorithm should have the ability of handling accurately the effect of the tissue density heterogeneity. It is better to use the lower-energy photons (6 MV) than to use the higher-energy photons (18 MV).

Humans↗

PubMedDate not supplied

Can treatment with angiotensin-converting enzyme inhibitors in elderly patients with moderate to severe chronic heart failure be improved by a nurse-monitored structured care program? A randomized controlled trial.

OBJECTIVE: The purpose of this study was to examine whether a nurse-monitored structured care program resulted in a more effective use of angiotensin-converting enzyme (ACE) inhibitors in elderly patients compared with standard care in patients with chronic heart failure (CHF). METHODS: Hospitalized patients were screened to identify individuals with CHF, age more than 65 years, New York Heart Association classification III to IV, and no contraindications to ACE inhibitor treatment. One hundred forty-five patients were randomized to a nurse-monitored structured care program that included uptitration of enalapril to a target dose of 10 mg twice a day or to standard care. Six-month follow-up data were collected. RESULTS: The mean age of the randomized patients was 81 years. Although the proportion of patients treated with an ACE inhibitor did not differ between structured care (70%) and standard care (64%), the number of patients with the target ACE inhibitor dose was significantly higher in the structured care group (26% versus 11% in the standard care group; P <.018). Treatment had to be discontinued in 26% of the patients because of adverse effects. CONCLUSION: The patients in this study were older than in previous intervention studies and had considerable comorbidity and reduced tolerance for ACE inhibitors. ACE inhibitor treatment was underused but improved with the structured care program, although achieved treatment levels were below those in the large intervention trials in patients with CHF.

Aged↗

PubMed2005

Levetiracetam in patients with cortical myoclonus: a clinical and electrophysiological study.

Levetiracetam is a new antiepileptic agent that exerts antimyoclonic effects. We conducted an open-label trial to evaluate the effect of levetiracetam in chronic cortical myoclonus of diverse etiologies and to determine whether levetiracetam affects electrophysiological findings. Sixteen patients, aged between 19 and 72 years, with refractory, chronic, cortical myoclonus were recruited. We assessed myoclonus severity with the Unified Myoclonus Rating Scale (UMRS). The electrophysiological study comprised jerk-locked averaging, somatosensory evoked potentials (SEPs), and long loop reflex I. Levetiracetam was administered add-on at a starting dose of 500 mg twice per day up to the target dose of 50 mg/kg/day. Patients were reevaluated clinically and electrophysiologically 2 weeks after the titration phase. Fourteen patients completed the trial. Posttreatment UMRS scores showed an improvement of myoclonus in all cases. Pretreatment, 9 patients had "giant" SEPs. Posttreatment, the amplitude of these SEPs was reduced by more than 50% in 3 of 9 patients, and the mean N20-P25 amplitude was reduced significantly. Pre- and posttreatment SEP amplitude was not related to myoclonus severity or duration. Levetiracetam is a promising and a relatively easy-to-test antimyoclonic agent, which has the potential to improve significantly the patient's disability; however, its long-term efficacy should be verified in larger controlled studies.

Adult↗

PubMed2001

Angiotensin II type 1 receptor blockade with 80 and 160 mg valsartan in healthy, normotensive subjects.

BACKGROUND: An 80-mg dose once or twice daily is the dose of valsartan frequently administered for treatment of hypertension. The target dose selected for the Val-HeFT trial in patients with chronic heart failure is 160 mg twice daily. The level and time course of angiotensin II type 1 (AT(1))-receptor blockade achieved by 160 mg valsartan have not been reported. METHODS AND RESULTS: Seven normotensive healthy subjects were assigned in random order to receive a single dose of placebo, 80 mg valsartan, and 160 mg valsartan at 7- to 10-day intervals. AT(1)-receptor blockade level (%) was determined by the pressure response to administration of exogenous angiotensin II. The pressure response to angiotensin II was measured at baseline and 2, 6, 12, and 24 hours after oral administration of placebo, 80 mg valsartan, and 160 mg valsartan. Eighty and 160 mg valsartan resulted in a significant and similar level of AT(1)-receptor blockade at 2 and 6 hours compared with placebo. The 160-mg dose resulted in a significantly greater level of AT(1)-receptor blockade than 80 mg at 12 and 24 hours. CONCLUSIONS: During the first 6 hours after oral administration of 80 and 160 mg valsartan the level of AT(1)-receptor blockade is similar. However, only 160 mg valsartan provides sustained AT(1)-receptor blockade over 24 hours.

Administration, Oral↗

PubMed2005

Effects of optimized heart failure therapy and anemia correction with epoetin beta on left ventricular mass in hemodialysis patients.

BACKGROUND: In chronic hemodialysis (HD) patients, the presence and degree of left ventricular hypertrophy (LVH) correlates with mortality. Previous studies have shown that interventions, such as anemia correction or treatment of hypertension and/or chronic heart failure (CHF), can result in moderate regression of LVH. The primary objective of our study was to investigate the effects of a multi-interventional treatment strategy on LVH in HD patients. METHODS AND RESULTS: In a series of 202 consecutive HD patients, we combined optimized CHF therapy, including beta-blockers (BB), ACE inhibitors and angiotensin receptor blockers (ARBs), to target doses with full anemia correction by epoetin beta (hemoglobin (Hb) target males 14.5 g/dl, females 13.5 g/dl). Serial echocardiograms were recorded every 3-6 months. Mean follow-up was 3.4 +/- 1.2 years. Mean Hb at baseline was 11.4 +/- 1.4 vs. 14.6 +/- 1.6 g/dl (p < 0.001) at study end. There was a significant reduction in left ventricular mass index (LVMI, 159 +/- 65 vs. 132 +/- 46 g/m2 (p < 0.001)), an improvement in left ventricular ejection fraction (LVEF, 60 +/- 15 vs. 66 +/- 12% (p < 0.01)) and in NYHA class (2.8 +/- 0.76 vs. 1.96 +/- 0.76 (p < 0.01)) from baseline to follow-up in the overall study population. In a subgroup of 70 patients, LVMI returned to normal (169 +/- 33 vs. 114 +/- 14 g/m2 (p < 0.001)) after 1.4 +/- 1 years. CONCLUSIONS: Our study shows that optimized CHF therapy, in combination with anemia correction to normal Hb targets, results in a significant reduction of LVH, an increase in LVEF and an improvement in NYHA class. Moreover, in contrast to previous studies, our data also demonstrate that complete regression and prevention of LVH in HD patients is possible.

Adrenergic beta-Antagonists↗

PubMed1999

[The CAPITOL study (Captopril Post Infarction Tolerance). A trial of progressive titration of captopril after myocardial infarct with left ventricular dysfunction].

The objective of CAPITOL (Captopril Post Infarction Tolerance) multicentre open trial was to study the tolerance of a protocol of titration of Captopril in patients with recent myocardial infarction complicated by left ventricular dysfunction. Five hundred and four patients, with a mean age of 62 +/- 12 years, were included during the hospital period in the 74 participating intensive care units, 9 +/- 6 days after myocardial infarction (ejection fraction 34 +/- 6%). After a 6.25 mg test dose of Captopril, the dosage was progressively increased to the target dose of 150 mg at the end of the first month. Of the 504 patients included, 343 finished the trial and 161 stopped the trial prematurely. At the end of the hospital period, 73% received 75 mg/day: at the first follow-up visit (27 +/- 16 days after inclusion), 59% had attained 150 mg/day, this proportion increasing to 71% at the end of the trial (79 +/- 33 days after inclusion). There was no significant change in blood pressure for the whole study population. However, the systolic blood pressure of the patients receiving 150 mg/day of Captopril at the end of the trial was slightly higher than that observed at the end of the hospital period (126 +/- 17 mmHg and 116 +/- 17 mmHg respectively, p = 0.006). Severe Intercurrent events were observed in 89 patients: 24 deaths, 7 recurrent infarctions, 58 hospital admissions (21 for cardiac failure, 15 for recurrence of angina, 11 aorto-coronary bypass operations, 7 coronary angioplasties, 2 cerebro-vascular accidents, 2 systemic emboli). Of the benign complications, hypotension was observed in 25% of patients, nearly half of which occurred during the hospital admission. The drugs prescribed in association with Captopril were Aspirin (78%), betablockers (57%), nitrate derivatives (42%) and diuretics (27%). Multivariate analysis showed 3 factors associated with good tolerance of the 150 mg dosage of Captopril: Killip Class I or II on admission, an ejection fraction > 30% and an initial systolic blood pressure > 100 mmHg. In conclusion, in this trial of dose titration, 3 out of 4 patients with myocardial infarction and left ventricular dysfunction, tolerated the 150 mg/day dosage of Captopril. Patients in the trial could also be treated with drugs recommended after myocardial infarction, in particular the betablockers. Arch Mal Coeur 1999: 92: 395-403.

Adrenergic beta-Antagonists↗

PubMed1995

Angiotensin-converting enzyme inhibitors post-myocardial infarction.

Results from SOLVD, SAVE, AIRE, GISSI-III, ISIS-IV, and the Chinese Captopril Trial suggest that therapy with ACE inhibitors, at least with enalapril, captopril, ramipril, and lisinopril, induce significant reduction in morbidity and mortality rates in patients with ischemic heart disease, myocardial infarction, and a wide range of ventricular function and myocardial infarction. SOLVD and SAVE results, in particular, demonstrate improved survival and reduced major ischemic events in patients with depressed systolic ventricular function. SOLVD points out that institution of ACE inhibitor therapy need not be done immediately post-myocardial infarction to accrue benefit. GISSI-III and ISIS-IV, on the other hand, suggest that use of ACE inhibitor drugs early post-myocardial infarction produces significant, albeit small, benefits when drugs are begun early post-event in conjunction with other routinely used therapeutic strategies. The prospective, well-designed, and well-controlled nature of these clinical trials, the consistency of their findings, and the high level of morbidity and mortality in placebo groups establish the importance of preventing ischemic events with the prescribed ACE inhibitors. Particularly important is the fact that none of these clinical trials were designed to determine optimal dose or frequency of administration of the ACE inhibitors chosen. Targeting dose principles were utilized and clinicians wishing to generate similar results in their own patient population should choose one of the ACE inhibitors studied and administer it in the manner described in hopes of achieving outcomes similar to those detailed in the summarized clinical trials. Finally, recommendations regarding post-myocardial infarction therapy with ACE inhibitors can be summarized. Patients having acute or remote infarction should have an assessment of ventricular function. All patients with depressed systolic function, whether they are or are not symptomatic, should receive a trial of an appropriate ACE inhibitor. Patients suffering an acute myocardial infarction should have an assessment of ventricular function early and, if the ejection fraction is low (probably < 50%), an appropriately chosen ACE inhibitor should be begun after 24 hours have elapsed. ACE inhibitor therapy should be begun in combination with other proven effective post-myocardial infarction treatment strategies. In patients with normal systolic function, advantages of ACE inhibitor therapy are less clear, but patients with large anterior wall myocardial infarction will likely benefit, even without objective evidence of left ventricular systolic dysfunction. Concomitant utilization of thrombolytic agents, aspirin, and beta blockers should not interdict use of ACE inhibitor therapy.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1999

Prevention of suboptimal beta-blocker treatment in patients with myocardial infarction.

OBJECTIVE: To review the published data and clinical guidelines on the use of beta-blockers in myocardial infarctions (MIs) and contrast that with actual clinical practice. DATA SOURCES: A MEDLINE search (January 1970-June 1999) was performed to identify all relevant articles. References from these articles were also evaluated for review if deemed important. DATA SYNTHESIS: Intravenous and oral beta-blockers have been proven to improve outcomes in patients with MIs in numerous clinical trials. In current clinical practice, only 15% of MI patients receive intravenous beta-blockers and long-term beta-blocker therapy is used in <40% of patients without contraindications. However, they could be safely administered to 40% and 70% of these patients, respectively. Furthermore, most of these patients are receiving doses far below those found beneficial in clinical trials. Many of the real and perceived contraindications to beta-blockers are reviewed to allow the practitioner to identify patients who are incorrectly excluded from beta-blocker therapy. Also discussed are special clinical situations in which the benefits observed during clinical trials may not apply. CONCLUSIONS: Beta-blockers are valuable drugs in the treatment of peri- and post-MI. In clinical practice, most patients are not treated or are inadequately treated with beta-blockers. Pharmacists should ensure that such patients actually have an absolute contraindication or unusual situation where therapy is not firmly indicated. Patients without absolute contraindications warrant titration to specific target doses or a target heart rate of 55-60 beats/min.

Adrenergic beta-Antagonists↗

PubMed2002

Comparison of forward planned conformal radiation therapy and inverse planned intensity modulated radiation therapy for esthesioneuroblastoma.

The purpose of this study was to compare dose distribution of inverse planned intensity modulated radiation therapy (IMRT) with that of conformal radiation therapy (SCRT) in the treatment of esthesioneuroblastoma, and to report initial clinical results. 13 patients with esthesioneuroblastoma were planned both with IMRT and SCRT using complete three-dimensional data sets. A target dose of 60 Gy was prescribed. We performed a detailed dose volume histogram analysis. Dose coverage was equal in both plans while dose distribution was more conformal to the target volume with IMRT. Mean and maximum dose of the brain stem, chiasm, optic nerves and orbits were lower using IMRT than SCRT. The reduction was significant regarding orbit and optic nerve (p<0.05). IMRT was superior in sparing of organs at risk compared with SCRT. The additional sparing by IMRT was positively correlated to the size of the target volume, which was evident with target volumes above 200 cm3. Treatment time was approximately 20 minutes per fraction using IMRT compared with 15 minutes per fraction using SCRT. We conclude that IMRT is both feasible and a valuable tool for more conformal dose distribution in the treatment of esthesioneuroblastoma and to spare organs at risk that are in critical relationship to the tumour. This advantage could be seen especially well in complex shaped target volumes above 200 cm3. Thus, using IMRT, risk of complications may be minimized and local tumour control may be increased.

Esthesioneuroblastoma, Olfactory↗

PubMed1999

Matched-pair analysis of hematopoietic progenitor cell mobilization using G-CSF vs. cyclophosphamide, etoposide, and G-CSF: enhanced CD34+ cell collections are not necessarily cost-effective.

Using matched-pair analysis, we compared two popular methods of stem cell mobilization in 24 advanced-stage breast cancer patients who underwent two consecutive mobilizing procedures as part of a tandem transplant protocol. For the first cycle, 10 microg/kg/day granulocyte colony-stimulating factor (G-CSF) was given and apheresis commenced on day 4 and continued for < or =5 days (median 3 days). One week after the first cycle of apheresis, 4000 mg/m2 cyclophosphamide, 400 mg/m2 etoposide, and 10 microg/kg G-CSF were administered for < or =16 days (cycle 2). Apheresis was initiated when the white blood cell (WBC) count exceeded 5000 cells/microL and continued for < or =5 days (median 3 days). Mean values of peripheral blood WBC (31,700+/-3200 vs. 30,700+/-3300/microL) were not significantly different between cycles 1 and 2. Mean number of mononuclear cells (MNC) collected per day was slightly greater with G-CSF mobilization than with the combination of chemotherapy and G-CSF (2.5+/-0.21x10(8) vs. 1.8+/-0.19x10(8) cells/kg). Mean daily CD34+ cell yield, however, was nearly six times higher (12.9+/-4.4 vs. 2.2+/-0.5x10(6)/kg; p = 0.01) with chemotherapy plus G-CSF. With G-CSF alone, 13% of aphereses reached the target dose of 5x10(6) CD34+ cells/kg in one collection vs. 57% with chemotherapy plus G-CSF. Transfusions of red blood cells or platelets were necessary in 18 of 24 patients in cycle 2. Three patients were hospitalized with fever for a median of 3 days after cycle 2. No patients received transfusions or required hospitalization during mobilization with G-CSF alone. Resource utilization (cost of drugs, aphereses, cryopreservation, transfusions, hospitalization) was calculated comparing the median number of collections to obtain a target CD34+ cell dose of 5x10(6) cells/kg: four using G-CSF vs. one using the combination in this data set. Resources for G-CSF mobilization cost $7326 vs. $8693 for the combination, even though more apheresis procedures were performed using G-CSF mobilization. The cost of chemotherapy administration, more doses of G-CSF, transfusions, and hospitalizations caused cyclophosphamide, etoposide, and G-CSF to be more expensive than G-CSF alone. A less toxic and less expensive treatment than cyclophosphamide, etoposide, and G-CSF is needed to be more cost-effective than G-CSF alone for peripheral blood progenitor cell mobilization.

Adult↗

PubMed2002

Risk group dependence of dose-response for biopsy outcome after three-dimensional conformal radiation therapy of prostate cancer.

BACKGROUND AND PURPOSE: We fit phenomenological tumor control probability (TCP) models to biopsy outcome after three-dimensional conformal radiation therapy (3D-CRT) of prostate cancer patients to quantify the local dose-response of prostate cancer. MATERIALS AND METHODS: We analyzed the outcome after photon beam 3D-CRT of 103 patients with stage T1c-T3 prostate cancer treated at Memorial Sloan-Kettering Cancer Center (MSKCC) (prescribed target doses between 64.8 and 81Gy) who had a prostate biopsy performed >or=2.5 years after end of treatment. A univariate logistic regression model based on D(mean) (mean dose in the planning target volume of each patient) was fit to the whole data set and separately to subgroups characterized by low and high values of tumor-related prognostic factors T-stage ( or=T2c), Gleason score ( 6), and pre-treatment prostate-specific antigen (PSA) ( 10 ng/ml). In addition, we evaluated five different classifications of the patients into three risk groups, based on all possible combinations of two or three prognostic factors, and fit bivariate logistic regression models with D(mean) and the risk group category to all patients. Dose-response curves were characterized by TCD(50), the dose to control 50% of the tumors, and gamma(50), the normalized slope of the dose-response curve at TCD(50). RESULTS: D(mean) correlates significantly with biopsy outcome in all patient subgroups and larger values of TCD(50) are observed for patients with unfavorable compared to favorable prognostic factors. For example, TCD(50) for high T-stage patients is 7Gy higher than for low T-stage patients. For all evaluated risk group definitions, D(mean) and the risk group category are independent predictors of biopsy outcome in bivariate analysis. The fit values of TCD(50) show a clear separation of 9-10.6Gy between low and high risk patients. The corresponding dose-response curves are steeper (gamma(50)=3.4-5.2) than those obtained when all patients are analyzed together (gamma(50)=2.9). CONCLUSIONS: Dose-response of prostate cancer, quantified by TCD(50) and gamma(50), varies by prognostic subgroup. Our observations are consistent with the hypothesis that the shallow nature of clinically observed dose-response curves for local control result from a patient population that is a heterogeneous mixture of sub-populations with steeper dose-response curves and varying values of TCD(50). Such results may eventually help to identify patients, based on their individual pre-treatment prognostic factors, that would benefit most from dose-escalation, and to guide dose prescription.

Biopsy↗

PubMed2003

Improved up-and-down designs for phase I trials.

We consider several designs from the family of up-and-down rules for the sequential allocation of dose levels to subjects in a dose-response study. We show that an up-and-down design can be improved by using more information than the most recent response. For example, the k-in-a-row rule uses up to the k most recent responses. We introduce a new design, the Narayana rule, which uses a local estimate of the probability of toxicity calculated from all previous responses. For the Narayana rule, as the sample size gets large, the probability of assignment goes to zero for dose levels not among the two (or three) closest to the target. Different estimators of the target dose are compared. We find that the isotonic regression estimator is superior to other estimators for small to moderate sample sizes.

Clinical Trials, Phase I as Topic↗

PubMed2000

Olanzapine pharmacokinetics in pediatric and adolescent inpatients with childhood-onset schizophrenia.

Well-designed studies investigating how pediatric or adolescent patients with mental disorders respond to and metabolize the newer antipsychotic drugs are practically nonexistent. Without such data, clinicians have difficulty designing appropriate dosage regimens for patients in these age groups. The results from a study of olanzapine pharmacokinetics in children and adolescents are described. Eight inpatients (ages 10-18 years) with treatment-resistant childhood-onset schizophrenia received olanzapine (2.5-20 mg/day) over 8 weeks. Blood samples, collected during dose titration and at a steady state provided pharmacokinetic data. The final evaluation (week 8) included extensive sampling for 36 hours after a 20-mg dose. Olanzapine concentrations in these eight pediatric patients were of the same magnitude as those for nonsmoking adult patients with schizophrenia but may be as much as twice the typical olanzapine concentrations in patients with schizophrenia who smoke. Olanzapine pharmacokinetic evaluation gave an apparent mean oral clearance of 9.6 +/- 2.4 L/hr and a mean elimination half-life of 37.2 +/- 5.1 hours in these young patients. The determination of the initial olanzapine dose for adolescent patients should take into consideration factors such as the patient's size. In general, however, the usual dose recommendation of 5 to 10 mg once daily with a target dose of 10 mg/day is likely a good clinical guideline for most adolescent patients on the basis of our pharmacokinetics results.

Adolescent↗

PubMed2003

Phase I trial using a time-to-event continual reassessment strategy for dose escalation of cisplatin combined with gemcitabine and radiation therapy in pancreatic cancer.

PURPOSE: The primary objective of this study was to determine the maximum-tolerated dose of cisplatin that could be added to full-dose gemcitabine and radiation therapy (RT) in patients with pancreatic cancer. PATIENTS AND METHODS: Nineteen patients were treated. Gemcitabine 1,000 mg/m(2) was administered over 30 minutes on days 1, 8, and 15 of a 28-day cycle. Cisplatin followed gemcitabine on days 1 and 15. The initial dose level of cisplatin was 30 mg/m(2), escalated to a targeted dose of 50 mg/m(2) using Time-to-Event Continual Reassessment Method. RT was initiated on cycle 1, day 1, in 2.4 Gy fractions to a total dose of 36 Gy. A second cycle of chemotherapy was planned following a 1-week rest. RESULTS: Four of eight patients experienced acute dose limiting toxicity at the 50 mg/m(2) cisplatin dose level. Patients treated at 30 and 40 mg/m(2) cisplatin dose level tolerated therapy without dose-limiting toxicity. Median survival was 10.7 months (95% CI, 5.4 to 18.2) for all patients, and 12.9 months (95% CI, 7.4 to 21.2) for those without metastasis. CONCLUSION: Cisplatin at doses up to 40 mg/m(2) may be safely added to full-dose gemcitabine and conformal RT. The Time-to-Event Continual Reassessment Method trial design allowed rapid completion of the study and confidence in the conclusion about the maximum tolerated dose, but accrued more patients to a dose level above the maximum tolerated dose than the typical phase I design. Local and systemic disease control and survival in this study cohort supports further investigation of gemcitabine-based RT and combination chemotherapy in this disease.

Aged↗

PubMed2000

[Addition of beta blockers in chronic heart failure].

Chronic heart failure is an increasing cause of hospital admission in the Netherlands and Belgium. Despite numerous medical treatment modalities, the mortality remains high. Recent placebo-controlled randomized studies suggest that the addition of beta-blockers in stabilized, optimally pretreated patients with chronic heart failure using angiotensin converting enzyme (ACE) inhibitors, diuretics and digitalis, is accompanied by an additional absolute decrease in mortality by about 5% and a relative decrease in mortality by about 35%. Also the number hospitalization frequency decreases. Initially, the beneficial effects of beta-blockers on symptoms are only minor or absent. During the initiation period some clinical deterioration may occur which has to be treated accordingly; these patients are, however, difficult to identify. Initiation has to be done using low doses and should be restricted to stabilized, optimally treated patients. Doses should only be increased every 2 to 4 weeks until target doses are reached. These findings must not be extrapolated automatically to all cases of heart failure, since patients in the trials may differ considerably from those encountered in general practice.

Adrenergic beta-Antagonists↗