Treatment of nocturnal asthma with pulsed-release albuterol

Sleep in asthma

Many patients with asthma experience worsening of symptoms at night. Understanding the mechanism of nocturnal asthma and the factors that exacerbate asthma during sleep would lead to better management of the condition.

Chronotherapeutics--a chronopharmaceutical approach to drug delivery in the treatment of asthma

Bronchial asthma is a chronic inflammatory disorder of the airways associated with airflow obstruction that is reversible spontaneously or with treatment. Bronchial asthma is a disease based on established circadian rhythm. The symptoms of asthma worsen during midnight to early morning and therefore it is required to deliver the drug in such fashion that effective treatment can be obtained during the time of asthma attacks. Chronotherapy is an approach that fulfills the criteria of drug delivery at a specific time as per the pathophysiological need of the disease, to improve patient compliance. The current article focuses on the chronotherapy of bronchial asthma, methodologies involved for the existing systems, recent updates and different chronopharmaceutical technologies currently available in the market. Chronotherapy with different categories of bronchial asthma medications also has been reviewed.

Asthma: Chronopharmacotherapy and the molecular clock

Bronchial asthma is characterized by chronic airways inflammation and reversible airflow limitation. In patients with asthma, symptoms generally worsen during the early hours of the morning, and pulmonary function often deteriorates at the same time, suggesting a role for chronopharmacotherapy. Several drugs for asthma have been developed based on chronopharmacology. Most medications employed for the chronotherapy of asthma are administered once at night with the goal of preventing chronic airway inflammation or development of airflow limitation. In addition to bronchodilators, the inhaled glucocorticosteroid ciclesonide is now available with once-daily dosing, which also improves patients' compliance. Numerous investigations have demonstrated the usefulness of chronotherapy for asthma, especially for patients with nocturnal asthma. This review focuses on chronotherapy of asthma, and also provides a molecular biological explanation for the influence of asthma medications on the clock genes.

Chronobiology and chronotherapy of allergic rhinitis and bronchial asthma

Study of the chronobiology of allergic rhinitis (AR) and bronchial asthma (BA) and the chronopharmacology and chronotherapy of the medications used in their treatment began five decades ago. AR is an inflammatory disease of the upper airway tissue with hypersensitivity to specific environmental antigens, resulting in further local inflammation, vasomotor changes, and mucus hypersecretion. Symptoms include sneezing, nasal congestion, and runny and itchy nose. Approximately 25% of children and 40% of adults in USA are affected by AR during one or more seasons of the year. The manifestation and severity of AR symptoms exhibit prominent 24-h variation; in most persons they are worse overnight or early in the morning and often comprise nighttime sleep, resulting in poor daytime quality of life, compromised school and work performance, and irritability and moodiness. BA is also an inflammatory medical condition of the lower airways characterized by hypersensitivity to specific environmental antigens, resulting in greater local inflammation as well as bronchoconstriction, vasomotor change, and mucus hypersecretion. In USA an estimated 6.5 million children and 15.7 million adults have BA. The onset and worsening of BA are signaled by chest wheeze and/or croupy cough and difficult and labored breathing. Like AR, BA is primarily a nighttime medical condition. AR is treated with H1-antagonist, decongestant, and anti-inflammatory (glucocorticoid and leukotriene receptor antagonist and modifier) medications. Only H1-antagonist AR medications have been studied for their chronopharmacology and potential chronotherapy. BA is treated with some of the same medications and also theophylline and beta2-agonists. The chronopharmacology and chronotherapy of many classes of BA medications have been explored. This article reviews the rather extensive knowledge of the chronobiology of AR and BA and the chronopharmacology and chronotherapy of the various medications used in their treatment.

Nocturnal asthma uncontrolled by inhaled corticosteroids: theophylline or long-acting beta2 agonists?

Asthma is an inflammatory disease of the airways that is frequently characterised by marked circadian rhythm. Nocturnal and early morning symptoms are quite common among patients with asthma. Increased mortality and decreased quality of life are associated with nocturnal asthma. Although numerous mechanisms contribute to the pathophysiology of nocturnal asthma, increasing evidence suggests the most important mechanisms relate to airway inflammation. According to international guidelines, patients with persistent asthma should receive long term daily anti-inflammatory therapy. A therapeutic trial with anti-inflammatory therapy alone (without a long-acting bronchodilator) should be assessed to determine if this therapy will eliminate nocturnal and early morning symptoms. If environmental control and low to moderate doses of inhaled corticosteroids do not eliminate nocturnal symptoms, the addition of a long-acting bronchodilator is warranted. Long-acting inhaled beta2 agonists (e.g. salmeterol, formoterol) are effective in managing nocturnal asthma that is inadequately controlled by anti-inflammatory agents. In addition, sustained release theophylline and controlled release oral beta2 agonists are effective. In patients with nocturnal symptoms despite low to high doses of inhaled corticosteroids, the addition of salmeterol has been demonstrated to be superior to doubling the inhaled corticosteroid dose. In trials comparing salmeterol with theophylline, 3 studies revealed salmeterol was superior to theophylline (as measured by e.g. morning peak expiratory flow, percent decrease in awakenings, and need for rescue salbutamol), whereas 2 studies found the therapies of equal efficacy. Studies comparing salmeterol to oral long-acting beta2 agonists reveal salmeterol to be superior to terbutaline and equivalent in efficacy to other oral agents. Microarousals unrelated to asthma are consistently increased when theophylline is compared to salmeterol in laboratory sleep studies. In addition to efficacy data, clinicians must weigh benefits and risks in choosing therapy for nocturnal asthma. Long-acting inhaled beta2 agonists are generally well tolerated. If theophylline therapy is to be used safely, clinicians must be quite familiar with numerous factors that alter clearance of this drug, and they must be prepared to use appropriate doses and monitor serum concentrations. Comparative studies using validated, disease specific quality of life instruments (e.g. Asthma Quality of Life Questionnaire) have shown long-acting inhaled beta2 agonists are preferred to other long-acting bronchodilators. Examination of costs for these therapeutic options reveals that evening only doses of long-acting oral bronchodilators are less expensive than multiple inhaled doses. However, costs of monitoring serum concentrations, risks, quality of life and otheroutcome measures must also be considered. Long-acting inhaled beta2 agonists are the agents of choice for managing nocturnal asthma in patients who are symptomatic despite anti-inflammatory agents and other standard management (e.g. environmental control). These agents offer a high degree of efficacy along with a good margin of safety and improved quality of life.

Sleep in patients with asthma and chronic obstructive pulmonary disease

Sleep abnormalities are common in patients with asthma and chronic obstructive pulmonary disease. Recent studies have provided new insight into the mechanisms involved in circadian changes in airway resistance, analyzed the effect of disease treatment on sleep quality, and re-examined issues relating to oxygen supplementation at night in patients with chronic obstructive pulmonary disease. Although providing new and useful information, some of these studies also raise new questions that will need answering in the future. This article reviews our current understanding of the complex interactions between sleep and lung disease in patients with asthma and chronic obstructive pulmonary disease.

Circadian rhythms in the pharmacokinetics and clinical effects of beta-agonist, theophylline, and anticholinergic medications in the treatment of nocturnal asthma

Published asthma consensus reports now acknowledge that asthma is a nocturnal disease in as many as 75% of those afflicted by this medical condition. Nonetheless, the treatment of this chronic obstructive pulmonary disease in the clinic continues to be based primarily on homeostatic considerations in that it relies on long-acting bronchodilator and other therapies formulated and scheduled to ensure constant or near-constant levels of medication during the 24h. The need of asthma patients prone to nighttime attacks is not the same during the day and night; the therapeutic requirements of patients who experience nocturnal asthma, especially ones with the more severe forms of the disease, are often not satisfied by conventional medications. The therapeutic response and patient tolerance to bronchodilator medications can be improved markedly when the medications are proportioned during the 24h as a chronotherapy, that is, when more medication is delivered during nighttime sleep than daytime activity, as verified by numerous studies. This article reviews how the body's circadian rhythms influence the pharmacokinetics and effects of commonly prescribed asthma therapies and addresses why and how they must be taken into consideration to increase the effectiveness of asthma treatment.

Parental perceptions of access to care and quality of care for inner-city children with asthma

The objective of this study was to describe perceptions of asthma care, morbidity, and health service utilization by parents of children with asthma presenting to an inner-city emergency department (ED). A cross-sectional survey was conducted in an urban pediatric ED, with a convenience sample of 466 parents of children receiving asthma treatment during a consecutive 6-week period in late fall 1995. Parents completed a 30-item survey including sociodemographic data, source of primary medical care and asthma care for their child, selected measures of access to care, and medications used by their child in the week prior to the ED visit. Perceived quality of asthma care was measured by six items (summary score = 0-6) reported to have been performed by the child's asthma doctor: discussion of home peak flow monitoring, child-specific triggers, dogs/cats, smoke, postexacerbation calling instructions, and provision of a written asthma management plan. Functional morbidity was measured by nights of poor sleep, days of cough, and school days missed due to asthma in the previous month. Among 325 patients with previously diagnosed asthma, 308 (97%) were reported to have a source of primary medical care. Of these, 126 respondents identified their primary care provider as the child's usual source of asthma care, while 158 identified the ED as the usual source. The groups did not differ by insurance status, ethnicity, or mean age of the child. Thirty-nine percent of children with the same provider for primary and asthma care compared with 15% of children reported to receive their asthma care predominantly in the ED had used inhaled steroids or cromolyn in the week prior to the ED visit (p < .0001). Children with the same provider for primary and asthma care had a higher mean quality score than children receiving asthma care in the ED (3.7 vs. 2.8, p < 0.0001), but there was no relationship between source of asthma care and functional morbidity. The ED remains the usual source of asthma care for many inner-city children. Among parents surveyed in the ED, there was a significant relationship between source of usual asthma care and quality of care, but a relationship between usual source of asthma care and functional morbidity could not be identified.

Sleep in asthma

The nocturnal worsening of asthma is a major cause of morbidity and mortality from this disease. The physiologic changes that occur during normal sleep can have adverse effects on breathing patterns, arousal responses, and airway clearance in asthmatics. Understanding of these alterations in airway mechanics and airway inflammation may lead to better management of this disease.