Evolving role of theophylline for treatment of chronic childhood asthma

Asthma

Asthma has been recognized as a disease since the earliest times. In the Corpus Hippocraticum, Hippocrates used the term “ασθμα” to indicate any form of breathing difficulty manifesting itself by panting. Aretaeus of Cappadocia, a well-known Greek physician (second century A.D.), is credited with providing the first detailed description of an asthma attack [13], and to Celsus it was a disease with wheezing and noisy, violent breathing. In the history of Rome, we find many members of the Julio-Claudian family affected with probable atopic respiratory disorders: Caesar Augustus suffered from bronchoconstriction, seasonal rhinitis as well as a highly pruritic skin disease. Claudius suffered from rhinoconjunctivitis and Britannicus was allergic to horse dander [529]. Maimonides (1136–1204) warned that to neglect treatment of asthma could prove fatal, whereas until the 19th century, European scholars defined it as “nervous asthma,” a term that was given to mean a defect of conductivity of the ninth pair of cranial nerves.

Treatment of childhood asthma: how do the available options compare?

The National Asthma Council of Australia suggests that "the aim of preventive therapy should be to enable patients to enjoy a normal life (comparable with that of non-asthmatic children), with the least amount of medication and at minimal risk of adverse events. The level of maintenance therapy should be determined by symptom control and lung function in the interval periods." The British Thoracic Society/Scottish Intercollegiate Guidelines Network states that the aims of the pharmacological treatment of asthma should be to control symptoms, prevent exacerbations and achieve the best possible lung function with minimal adverse effects. We have used the current published international guidelines to highlight the international differences in management recommendations, and compared the possible pharmacological options with a focus on the above ideals. Cromones have been used for many years in childhood asthma. Most evidence suggests they now have little role. Regarding inhaled corticosteroids (ICS), beclomethasone and budesonide are essentially similar in their efficacy. Fluticasone propionate is equally as effective at one-half the equivalent dose of budesonide or beclomethasone. Adverse effects are rare in dosages <400 microg/day of budesonide and beclomethasone or <200 microg/day of fluticasone propionate, but may occur in individual patients. Relevant clinical adverse effects are rare and pharmacological systemic effects are less noticeable with budesonide and fluticasone propionate than with beclomethasone, but data are conflicting. Long-acting beta2-adrenoceptor agonists (beta2-agonists) are recommended once low-dose ICS have failed to control symptoms. The main pharmacological difference between the agents is that formoterol is a full beta2-adrenergic agonist, whereas salmeterol is a partial agonist at the beta2-adrenoceptor and has a unique pharmacological action. The main clinical distinction between these two agents is that their onset of bronchodilation differs. Bronchodilation begins at about 3 minutes after inhalation of formoterol, which is similar to the short-acting agents, whereas salmeterol has a much slower onset of action at about 15-30 minutes. The many in vitro differences between the two drugs are probably not clinically relevant. There are no comparative pediatric data on the leukotriene modifiers to make clear recommendations.

The association of gastroesophageal reflux disease with asthma and chronic cough in the adult

Gastroesophageal reflux disease (GERD) is a common condition which is particularly prevalent in patients with asthma and chronic cough. Physiologic changes caused by asthma and chronic cough promote acid reflux. GERD is also considered by many investigators as a factor contributing to airway inflammation. An etiological relationship between GERD and asthma/chronic cough and vice versa has been supported by a large number of experimental and clinical findings and refuted by others. Although further controlled studies are needed to clarify this relationship, GERD and asthma/chronic cough appear to be linked to each other. The association of GERD with asthma and chronic cough involves nerve reflexes, cytokines, inflammatory and neuroendocrine cells and, in some patients, tracheal aspiration of refluxing gastric fluids. GERD may present with typical symptoms but can also be asymptomatic. Sensitive methods for diagnosing GERD are available, which include esophageal pH monitoring, acid provocative tests, modified barium swallow and endoscopy. Consideration of the association of GERD with asthma and chronic cough is of practical value in the management of chronic cough or asthma resistant to treatment. Treatment of GERD in patients with asthma has been consistently shown to improve respiratory symptoms but not necessarily pulmonary function tests. Surgical treatment can be a useful and cost-effective approach in selected patients with asthma and GERD.

Furosemide: progress in understanding its diuretic, anti-inflammatory, and bronchodilating mechanism of action, and use in the treatment of respiratory tract diseases

Accumulated experimental and clinical data suggest that adrenocorticosteroids and/or endogenous ouabain-like substances may play an important role in the mechanism of furosemide diuretic action. It was reported that the drug is highly bound in the adrenals, lungs, kidney, spleen, and liver. In patients with liver cirrhosis, furosemide exerted a markedly decreased natriuretic effect compared with normal subjects, and the plasma levels of circulating endothelin and atrial natriuretic factor (ANF) were significantly elevated. In neonates, after administration of furosemide, the urinary excretion of endothelin-1 and aldosterone increased markedly, and it is known that endothelin may release ANF and aldosterone in a dose-dependent manner. Furosemide was used to stimulate zona glomerulosa, whereas ANF decreased the production of steroids in zona glomerulosa and fasciculata cell culture owing to stimulation by various factors. Because the concomitant use of ANF and furosemide appeared to be diuretically effective in newborns after cardiac surgery, one may suggest that furosemide competes with ANF for its effects on the adrenals. Furosemide administered by inhalation exerted a protective effect on allergic and perennial nonallergic rhinitis and was effective in preventing the postsurgical recurrence of nasal polyposis. The drug can also be used as an antiasthmatic agent. In preterm ventilator-dependent infants with chronic lung disease, aerosolized furosemide improved pulmonary function with no marked effect on diuresis. In adults and children with asthma, furosemide exerted a protective effect against bronchoconstriction induced by several indirect stimuli similar to that of disodium cromoglycate or nedocromil. Aerosolized furosemide had a preventive effect also on bronchoconstriction induced by inhaled lysine acetylsalicylate in patients with aspirin-sensitive asthma. In high-dose beclomethasone-dependent asthma, inhaled lysine acetylsalicylate and furosemide exerted a mutually potentiating antiasthmatic activity, allowing considerable sparing of the inhaled steroid. It is proposed that this effect may be explained by the corticosteroid-sparing action of lysine released from the lysine acetylsalicylate molecule because similar beneficial effects were also obtained after the concomitant use of epsilon-aminocaproic acid (whose chemical structure is almost the same as that of lysine) and prednisone. Furosemide exhibited an anti-inflammatory effect through inhibition of production and release of cytokines interleukin (IL)-6, IL-8, and tumor necrosis factor-alpha from peripheral mononuclear cells, which may have a beneficial effect on local inflamed tissue imbalance in the ratio of different cytokines, thus improving the sensitivity of target cells to endogenous glucocorticosteroids.

How pediatricians manage asthma in Thailand

Currently, there is no existing information regarding prescribing practices for the management of childhood asthma among pediatricians in Thailand. In order to evaluate the management standards for childhood asthma in Thailand, 400 self-administered questionnaires were randomly mailed to nonacademic pediatricians throughout Thailand, asking questions about their preferences in the treatment of childhood asthma. One hundred and seventy-four of these 400 questionnaires were returned (a response rate of 43.5%). Data were analyzed using the descriptive module of the Epi-info 6 program. For acute asthma, 17% of the respondents used objective measures such as peak flow meters in assessing asthma severity and severity of acute asthma attacks. The drug of first choice for treating acute attacks was a nebulized beta-agonist q 20 min (81.8%). Although 93% indicated that they had used theophylline for treating acute attacks, most would reserve the drug for patients with severe symptoms. Corticosteroids were reserved for those with severe attacks (91.7% both for clinic and for in-hospital settings). Hydrocortisone was the most preferred corticosteroid preparation (59.8%). Ninety-seven percent used antibiotics in treating acute asthma, but only with appropriate indications. For chronic asthma, a strong preference was observed for oral beta-agonists as the bronchodilator of choice (88%). For moderately severe asthmatics, theophylline was still preferred by 41% of the responders. Among prophylactic agents, ketotifen was the most favored drug (90.4%), whereas inhaled steroids and cromolyn were chosen by 9.6% and 2.4%, respectively. Eighty-five percent indicated that they would prescribe prophylactic agents for 1 year or less. Forty-two percent never considered allergy evaluation as a part of a workup for childhood asthma. Certain prescribing practices of childhood asthma management in Thailand were observed among pediatricians, i.e., 1) low frequency of using objective measures in assessing asthma severity among pediatricians; 2) frequent use of theophylline and antibiotics in the treatment of acute asthma; 3) late introduction of corticosteroids in treating acute asthma; 4) preference for oral bronchodilators; and 5) preference of ketotifen as the prophylactic drug of choice. This survey provides baseline data and will aid in the evaluation of management guidelines for childhood asthma in Thailand.

Efficacy of IV aminophylline as a supplemental therapy in moderate broncho-obstructive crisis in infants and preschool children

The aim of the present study was to investigate the efficacy of iv aminophylline as a supplemental therapy for wheezy infants and preschool children who still present moderate broncho-obstruction after treatment with nebulized fenoterol. A prospective randomized, double blind, placebo-controlled trial was conducted in a Paediatric Emergency Room. The major selection criteria for patients>> inclusion were age between 1 and 7 years, a wheezy episode lasting less than 2 days which failed to respond to three sequential fenoterol nebulizations, a Wood-Downes score between 3 and 6, and a history of at least two similar episodes. Exclusion criteria were radiologically-identified pulmonary condensation, recent use of corticosteroid and/or theophylline drugs, and previous diagnosis of chronic conditions. A sample of 43 cases was selected: 24 in Group A and 19 in Control Group B. All patients were submitted to nebulization with fenoterol and intravenous hydrocortisone for a maximum period of 24 h. Only Group A patients received iv aminophylline (6 mg/kg in bolus and 1.2 mg/kg per h for maintenance schedule). Treatment efficacy parameters established for the two groups were based on the Wood-Downes clinical score. Throughout the study, the average clinical scores and the discharge rate were similar for both groups. The average stay in the Emergency Room was 12.5 h for Group A and 14.6 h for Control Group B. In conclusion, the use of supplemental iv aminophylline for moderate broncho-obstructive crisis in wheezy infants and preschool children did not add therapeutically significant results to the usually prescribed combination of nebulized beta-adrenergic and intravenous corticosteroid drugs.

Theophylline: recent advances in the understanding of its mode of action and uses in clinical practice

Theophylline, a drug that has been used for several decades, has several different actions at a cellular level, including inhibition of phosphodiesterase isoenzymes, antagonism of adenosine, enhancement of catecholamine secretion, and modulation of calcium fluxes. Recently, theophylline was found to have several immunomodulatory and anti-inflammatory properties, and thus interest in its use in patients with asthma has been renewed. The use of theophylline in the treatment of asthma and chronic obstructive pulmonary disease has diminished with the advent of new medications, but theophylline remains beneficial, especially in the patient with difficult refractory symptoms. In the future, theophylline may be used as treatment for bradyarrhythmias after cardiac transplantation, prophylactic medication to reduce the severity of nephropathy associated with intravenous administration of contrast material, therapy for breathing problems during sleep, and treatment for leukemias.

Medications used by children with asthma living in the inner city

OBJECTIVE

The purpose of the study was to examine medication use reported by families participating in an urban school-based community intervention program and to relate this use to other social and medical variables.

DESIGN

The design of the study was a cross-sectional questionnaire survey.

SETTING

Patients and their families recruited from elementary schools in a community setting were interviewed between December 1991 and January 1992.

PARTICIPANTS

A total of 508 children with asthma were identified by school health records and teacher surveys. Their families confirmed the diagnosis and agreed to enter the study. Questionnaires were completed by 392 families.

INTERVENTION

The 392 families participated in a controlled trial of asthma education after providing the data that are the basis of this report.

RESULTS

More than half of the children took two or more medications for asthma. Thirty-one percent took theophylline alone or in combination with an adrenergic agent; 11% took some form of daily antiinflammatory medication, either cromolyn (8%) or inhaled steroids (3%). The pattern of medication use related to measures of severity and to regular visits to physicians or nurses. In general, however, children were undermedicated. A total of 78 children (20%) reported no medication or over-the-counter medication use, although 37% reported asthma severe enough to be associated with >/=20 days of school missed per month, and 37% had had an emergency room visit for asthma in the past 6 months. More than half of children >/=9 years old supervised their own medication.

CONCLUSIONS

We concluded that undermedication is common in poor children with asthma living in urban areas. Antiinflammatory medications are used less commonly than in the general population, and theophylline is used more often. School children may be likely to supervise their own medication.

Treatment of childhood asthma. Options and rationale for inhaled therapy

Epidemiological studies suggest the prevalence of asthma is increasing, though some remain sceptical as to the magnitude or indeed the presence of an increase. However, despite improved diagnosis and the availability of the potent drugs now available there remains considerable respiratory morbidity associated with asthma. It is clear from a number of studies that failure to deliver drugs to the lungs when using inhaler devices is a factor contributing to this high level of morbidity. Failure of drug delivery may result from the prescribing of inappropriate devices, failure to use devices appropriately or failure to comply with a treatment regimen. For most of the currently available forms of asthma therapy there are significant advantages to be gained from administering them in aerosol form. The benefits to be derived from administering these drugs as an aerosol include a rapid onset of action for drugs such as beta-agonists and a low incidence of systemic effects from drugs such as beta-agonists and corticosteroids. Over the past 25 years our understanding of the nature of asthma has changed. Though this has been reflected in the emphasis on inhaled corticosteroid therapy in recent guidelines, it has not been reflected in the range of inhaler devices available. Manufacturers continue to place drugs such as corticosteroids in the same devices as short acting beta-agonists even though the requirements for these different drug classes are very different. It is likely that this contributes to suboptimal therapeutic responses with inhaled corticosteroids. However, the variability associated with current delivery systems is relatively small compared with the variability introduced by poor compliance. There is no work currently available to indicate how the use of cheap disposable devises which do not incorporate any form of positive feedback influence compliance with inhaled steroids. Optimising aerosolised drug delivery in childhood involves consideration of the class of drugs, the particular drug within a class but more importantly, the age and abilities of the child. Devices must be selected to suit a particular child's needs and abilities. Devices utilising tidal breathing are generally used such as spacing chambers or, less commonly these days, nebulisers. A screaming or struggling child, or failure to use a closely fitting mask, reduces drug delivery to the lungs enormously. Failure to respond to inhaled therapy in early childhood may be attributable to failure of drug delivery. Drug delivery in early childhood using current devices remains more an art than a science.

Characteristics of inner-city children with asthma: the National Cooperative Inner-City Asthma Study

Asthma morbidity has increased dramatically in the past decade, especially among poor and minority children in the inner cities. The National Cooperative Inner-City Asthma Study (NCICAS) is a multicenter study designed to determine factors that contribute to asthma morbidity in children in the inner cities. A total of 1,528 children with asthma, ages 4 to 9 years old, were enrolled in a broad-based epidemiologic investigation of factors which were thought to be related to asthma morbidity. Baseline assessment included morbidity, allergy evaluation, adherence and access to care, home visits, and pulmonary function. Interval assessments were conducted at 3, 6, and 9 months after the baseline evaluations. Over the one-year period, 83% of the children had no hospitalizations and 3.6% had two or more. The children averaged 3 to 3.5 days of wheeze for each of the four two-week recall periods. The pattern of skin test sensitivity differed from other populations in that positive reactions to cockroach were higher (35%) and positive reactions to house dust mite were lower (31%). Caretakers reported smoking in 39% of households of children with asthma, and cotinine/creatinine ratios exceeded 30 ng/mg in 48% of the sample. High exposure (> 40 ppb) to nitrogen dioxide was found in 24% of homes. Although the majority of children had insurance coverage, 53% of study participants found it difficult to get follow-up asthma care. The data demonstrate that symptoms are frequent but do not result in hospitalization in the majority of children. These data indicate a number of areas which are potential contributors to the asthma morbidity in this population, such as environmental factors, lack of access to care, and adherence to treatment. Interventions to reduce asthma morbidity are more likely to be successful if they address the many different asthma risks found in the inner cities.