Monitoring Serum Theophylline Levels (original) (raw)
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Evaluation of a Noninstrumented Disposable Method for Quantifying Serum Theophylline Concentrations
Pharmacotherapy: The Journal of Human Pharmacology and Drug Therapy
Study Objective. To compare the performance of a new point‐of‐care theophylline assay (AccuMeter) with that of a standard laboratory assay (TDx), and another point‐of‐care method (AccuLevel).Design. Prospective evaluation of consecutive patients receiving theophylline.Setting. University‐based, ambulatory, allergy‐pulmonary clinic.Patients. Forty subjects receiving maintenance theophylline therapy for asthma.Interventions. Theophylline concentrations obtained from AccuMeter, TDx and AccuLevel were compared.Measurements and Main Results. The error, or difference, between TDx and AccuMeter results in 40 subjects on maintenance theophylline described accuracy. Mean error, an estimate of bias, was 1.1 (95% CI 0.72–1.5), 0.67 (0.34–1.0), and 0.98 (0.79–1.2) μg/ml for AccuMeter capillary, serum, and heparinized blood samples. Square root of the mean squared error, an estimate of precision, was 1.6 (1.2–2.0), 1.22 (0.90–1.5), and 1.14 (0.96–1.3) μg/ml for AccuMeter capillary, serum, and he...
The new trends in theophylline therapy
Bosnian journal of basic medical sciences / Udruzenje basicnih mediciniskih znanosti = Association of Basic Medical Sciences, 2002
Sustained-release theophylline pellets formulation for once-daily evening administration significantly improved patients compliance and adjusted serum levels profile of the drug. The patients conversion from i.v. to p.o. therapy is one of the most critical steps in the treatment of asthma according to its chronopathophysiological character. In our study we have examined safety and efficiency of this conversion in twelve hospitalised asthmatic patients who were given the new sustained-release theophylline pellets formulation for once-daily evening administration. The lung function parameters (FEV1, VC, RV, and Rt) and serum theophylline concentrations were monitored. So, the values obtained for the last day of i.v. therapy and the fifth day of p.o. therapy were compared. We found that 75% of the patients had no change or improved lung function on the conversion. Our results indicate that this conversion from i.v. to p.o. theophylline therapy is safe and could be efficacious. Also, th...
A Single-Blind Crossover Study of Two Different Slow Release Theophylline Preparations
Journal of International Medical Research, 1988
In a single-blind crossover study, two slow release theophylline preparations were evaluated in 18 patients with chronic bronchitis or asthma without cardiac, renal or liver disease. After randomization into two groups, patients were treated, in a crossover study design, with 600 mg choline theophyllinate or 300 mg anhydrous theophylline administered orally every 12 h for 7 days. A 2-day washout period separated the two periods of treatment evaluation. Blood samples in which plasma theophylline concentration was to be measured were taken at 7.30 a.m., 2.00 p.m. and 7.30 p.m. during the last 5 days of therapy with each drug. The mean fluctuation in plasma theophylline concentration was ≤40% in all 18 patients taking choline theophyllinate yet in only 15 (83%) patients administered anhydrous theophylline. Salbutamol inhaler was more frequently required for the relief of bronchospasm when taking anhydrous theophylline than when taking choline theophyllinate (total of 41 vs 25 puffs, re...
European Journal of Clinical Pharmacology, 1982
Fifteen adult chronic asthmatic patients were studied on 6 consecutive days of the second week of treatment with a new sustained release theophylline formulation, and 8 were again studied after three months on the same dosing regimen (375 mg b.i.d.). Serum theophylline concentrations were maintained in the therapeutic range (peak-19.7 _ 5.0 ~g/ml; trough-13.0 ___ 3.2 ~tg/ml) throughout the 12 hour dosing interval, and were greater than 75% of the peak concentration over 8.6 +__ 2,9 h. A degree of drug accumulation was evident in that the 1-h and 5-h levels rose from 12.2 + 4.1 and 14.5 _ 4.8 ~xg/ml during the second week to 16.9 + 4.6 and 18.4 + 4.5 lxg/ml, respectively, at three months. Between-patient differences accounted for 61%-71% of the total variation in steady state theophylline concentrations. After accounting for differences due to sampling time and assay error, unexplained random, within-individual variability amounted to 11%-18% of the total. Quantitative estimation of these components of variability may be incorporated into dosage forecasting methods based on single determinations of serum concentration.
Theophylline for Chronic Asthma: Rationale for Treatment, Product Selection, and Dosage Schedule
Allergy and Asthma Proceedings, 1983
Theophylline has emerged as one 0/ the mOST useful non-corticosteroid agents available for suppressing :rmptoms in the patient with chronic asthma. Maximal benefit, however, requires appreciation of the pharmacodynamics and pharmacokinetics o.l'This drug. A t concentrations between 10 and 20 mcg/ mi. optimal likelihood o.l benefit without toxiciTY is afTained and sympToms of asthma are virTualll' eliminated in many patients and are significant Zl' decreased even in paT ients requiring inhaled or oral COrTicosteroids. InrerpaTient variability in the rate ol drug elimination. however. resuiTs in a wide range o.l doses To atTain these serum concentrations. Initiation of therapy WiTh low doses and the determination o.ffinal dosage by measurement o.lserum theophylline concentration is essentialfor safe and eflective use. A simple and efficient dosing schedule has been developed that virtua/~l' eliminates problems of intolerance ol The drug and results in all buT about 1% o.l'children and almost as many adults ToleraTing theophylline without adverse effects. Sustained-release theophylline preparations, when relia-b~l' and complete~l' absorbed. o.ffer major therapeutic advantage by minimizing fluctuations in serum concen-Pro.
European Journal of Clinical Pharmacology, 1981
The pharmacokinetics of theophylline following a single intravenous dose of aminophylline were determined in 8 asthmatic patients in each of the acute, the recovery and the remission phases. The overall results for mean plasma theophylline clearance (78.6 _+ 33.3 ml/kg/h), plasma theophylline half-life (4.14 +_ 1.36 h) and apparent volume of distribution (0.41 _+ 0.066 l/kg) are in accordance with previously published values. There was no general statistically significant difference in any of the pharmacokinetic parameters when results from the acute and remission phases were compared. However, certain patients showed reductions in plasma theophylline clearance in the acute phase of the illness such that a dosage regimen standardised during remission may cause toxicity if continued in the acute episode. It is suggested that monitoring the plasma theophylline levels is desirable in all patients in the acute episode.
Pharmacokinetic analysis of the disposition of intravenous theophylline in young children
The Journal of Pediatrics, 1976
Pharmacokinetic analysis of the disposition intravenous theophylline in young children of The disposition of a single intravenous dose of theophylline, 3.2 mg/kg, was studied using a high-pressure liquid chromatographic assay in ten asthmatic children one to four years of age. The mean plasma theophylline clearance was 0.100 +_ 0.036 1/kg/hr, k~ 0.49 ++_ 0.30 hr L, Btt/z 3.38 +_ 1.11 ht; atV2 0.13 +_ 0.09 hr, and V1 0.25 + 0.13 1/kg. Plasma theophylline clearance was approximately 40% greater in these children than that reported in adults, mainly due to an increased rate of drug elimination. Large interindividual differences were observed. Analysis of data using either a two-or one-compartment model yielded almost idel~tical dosage regimens designed to rapidly achieve and maintain a chosen plasma theophylline concentration. Calculations based upon mean values of pharmacokinetie constants predict that a maintenance dose rate for aminophylfne of 30 mg/kg/day, after a loading dose of 5.6 mg/kg, would rapidly achieve and maintain a mean steady-state plasma concentration of theophylline of 10 mg/ l. Potential toxicity of such a regimen has not been excluded, since therapeutic trials (with achievement 'of steady state) have not yet been conducted.
Intraindividual variability in theophylline pharmacokinetics in subjects with mild/moderate asthma
Journal of Allergy and Clinical Immunology, 1987
Intrasubject variability in theophylline pharmacokinetics was assessed in six subjects with mild/moderate asthma. On four occasions, each separated by a minimum of 3 weeks, a 6 mg/kg intravenous aminophylline dose was infused during 30 minutes, and multiple blood samples were obtained thereafter. The pharmacokinetic parameters of clearance (CI), volume of distribution, and half-life were determined by noncompartmental analysis. There was evidence for within-subject variability in these parameters. In comparison to the first study day, CI changed by >15% in all but one subject and by >25% in two of six subjects. Changes in half-life exceeding 25% of the value observed on the first study day occurred in three of six subjects. Within-subject coefficient of variation for CI was 14.9% (range 3.9% to 33.3%) and 14.4% (range 5.8% to 24.3%) for half-life. Volume of distribution, however, was a more stable parameter with a within-subject coefficient of variation of 7.2% (range 2.3% to 11.1%). Thus, within-subject changes in the pharmacokinetics of theophylline do exist over time. These data suggest that close monitoring of patients receiving theophylline is warranted, particularly when theophylline concentrations are maintained at either extreme of the therapeutic range. (J ALLERGY CLIN IMMUNOL 1987;80:33-8.) Theophylline has recently been demonstrated to exhibit apparent random changes in pharmacokinetic disposition within the same subject.'' ^ This type of unpredictable pharmacokinetic behavior has several implications. First, from a therapeirtic standpoint, patients maintained at tiie extremes of the therapeutic range (10 to 20 p-g/ml) would require close monitoring for signs of toxicity or exacerbation of symptoms as a result of unpredictable changes in serum theophylline concentrations. Additionally, bioavailability studies depend on the CI of the study drug to remain constant between study days. A change in CI within subjects could influence the interpretation of these studies. For example, if the AUC of a drug was observed to be lower during the administration of a sustained-release preparation, as compared to that ob-
Theophylline Therapy in Ambulatory Asthmatic Patients: Efficacy and Pharmacokinetics
Allergy and Asthma Proceedings, 1983
Theophylline has long been recognized as a potent bronchodilator. Pharmacodynamic and pharmacokinetic studies have greatly increased its efficacious use while decreasing the serious toxicity problems initially observed. Careful attention to recently established dosage guidelines can great~y minimize most untoward side effects.