Measurement Of Theophylline Concentration Research Articles

Analysis of Plasma Concentrations of Theophylline in Smoking and Nonsmoking Patients with Asthma.

BACKGROUND:While dosing theophylline in asthmatics, we should consider that a lot of medicines, substances, conditions and diseases affect the clearance of theophylline, such as smoking, macrolide antibiotics, barbiturates, oral contraceptives, heart and liver insufficiency, alcohol, calcium-antagonists, pneumonia, viral infections, hypoxemia, etc.AIM:The aim of the study is to investigate the concentrations of theophylline during the day in smoking and nonsmoking patients with asthma.MATERIAL AND METHODS:We have estimated the concentrations of theophylline 6 times daily by the HPLC method (Keith Muir, J Chromatography) in 20 smoking and 20 nonsmoking asthmatic patients, who were treated with theophylline sustained-release tablets 175 mg twice daily.RESULTS:In the first group of 20 nonsmoking patients we obtained constant therapeutic and optimal concentrations of theophylline. In the second group of 20 smoking asthmatics the concentration of theophylline in plasma, in 8pm and 8am the next day was very low.CONCLUSION:Because in smokers we have increased clearance and the decreased half- life of theophylline, and in order to prevent the night time life-threatening attacks, it is necessary to recommend maximal doses of theophylline, especially in the evening. According to the study, dosage should be individualized in order to optimize the treatment based on the measurement of theophylline concentration in plasma.

Theophylline for the treatment of bronchial asthma: present status.

Current Japanese asthma guidelines recommend theophylline as an additional regimen to inhaled beta-agonists (on demand use) and inhaled corticosteroids (beclomethason dipropionate 200-1200 micrograms/day or fluticason propionate 200-800 micrograms/day) for patients whose asthma is not controlled completely. Similar recommendations are made in the International Consensus Report on Diagnosis and Treatment of Asthma. Recent advances in the understanding of its actions, especially regarding the antiinflammatory and immunomodulatory effects of low doses of theophylline, encourage its appropriate use in asthma treatment. Furthermore, asthma and chronic obstructive pulmonary disease (COPD) are considerably common diseases, and the economic benefits associated with the use of a relatively inexpensive, once or twice daily oral drug (intravenous infusion, if necessary) could be of importance. But, because of its narrow therapeutic range, dosage must be individualized in order to optimize the treatment based on the measurement of theophylline concentration in serum. Theophylline is an old medication with new forms. When used effectively and safely, it can have significant clinical benefits for patients. This paper intends to review the effectiveness of theophylline--historically and contemporarily.

Determination of theophylline clearance in South African children.

Theophylline clearance values in South African children were determined using 400 serum theophylline concentration measurements gathered from 109 compliant outpatients during their normal routine care. Population pharmacokinetic analysis was done using the Non-Linear Mixed Effects Model (Nonmem) to analyse the data. Nonmem was also used to estimate the influence of fixed effects (weight, age, race, gender etc) on clearance and its interindividual variability. Gender, age, and weight raised to an iterated exponent were found to be the most important demographic fixed effect parameters influencing clearance. Race was not found to be important. The weight-adjusted values of theophylline clearance decreased with increasing age. The actual values expressed in l.h-1.kg-1 were 0.0949 for children aged 1-5 y; 0.0813 for children aged 5-9 y, and 0.0660 for children of 9-16 y. The values are similar to those reported in other studies.

Measurement of theophylline concentration in asthmatic patients with nasal polyps using a new kit (AccuLevel®)

Measurement of theophylline concentration in asthmatic patients with nasal polyps using a new kit (AccuLevel®)

THEOPHYLLINE CONCENTRATION MEASUREMENTS IN SERUM OR SALIVA FOR THERAPY MONITORING IN BRONCHIAL ASTHMA

Theophylline concentrations in serum and in saliva obtained without and with stimulation (dil. citric acid) of 20 patients in the age range of 5-19 years on a long term theophylline therapy were simultaneously assessed within 6 hours after drug intake; at the same time several parameters of the lung function were taken. The theophylline concentration measurements were performed gaschromatographically. The saliva concentrations obtained without stimulation very strongly correlated with the serum concentrations (r=0,98; mean deviation from the regression line 0,70/ug/ml). The saliva concentrations obtained with stimulation revealed a significantly weaker correlation with the serum concentrations (r=0,82). A dependence of the concentrations from the salivation rate (m1/2 minutes) could be identified (r=0,66) in the saliva obtained with as well as in that obtained without stimulation; this dependence exists both intra- and interindividually. Reliability and evidence of the saliva concentrations obtained without stimulation can be further increased by measurement of the secreted saliva volume per period of time.

Why measure plasma theophylline concentrations

SummaryStudies have been carried out with a number of theophylline preparations, both in normal subjects and inpatients with obstructive airways disease, to obtain information about plasma theophylline concentrations. With some of the formulations studied, ‘usual’ or recommended doses failed to produce plasma theophylline levels within the optimum range of 10 to 20 μg/ml. Because of the large inter-individual variation between patients, it would appear that dose requirements with different drugs should be carefully monitored and that regular plasma theophylline concentration measurements should be considered in patients with obstructive airways disease, particularly when clinical management is difficult.

Paroxysmal supraventricular tachycardia during theophylline therapy in a premature infant

An episode of supraventricular tachycardia occurred in an infant born at 31 weeks' gestation after three days of therapy with theophylline 3.5 mg/kg every six hours. The infant had a plasma theophylline half-life of 24.7 hours and a low plasma theophylline clearance of 12.7 ml/kg/hour. The plasma theophylline concentration at the time of the arrhythmia was about 42 mg/l. The extent of drug accumulation with these kinetic characteristics is emphasized. Serious adverse effects due to theophylline may occur with few signs of symptoms of impending toxicity. Plasma theophylline concentration measurements are valuable in avoiding such toxicity.