A single dose of preventer inhaler in the afternoon may lead to better asthma control say researchers investigating why symptoms are worse at different times of day.
While the study was small, it points to a potentially intriguing way to manage the condition, experts said.
The UK study compared 400 µg beclomethasone taken in the morning only, the same dose but at 3-4pm or a standard twice daily dose of 200 µg at either end of the day.
Responses were tested in 21 people with mild to moderate asthma who were randomly assigned to each of the three groups for 28 days before having a fortnight gap and then switching to one of the other dosing regimens until they had done all three.
Spirometry readings and blood biomarkers including inflammatory cells, levels of cortisol and salbutamol from reliever inhalers were measured every six hours for 24 hours at the start and end of each-28-day period.
Researchers found that the afternoon dosing regimen may be more effective at preventing nocturnal worsening of symptoms.
Compared with baseline measurements, all groups saw improved night-time lung function.
But the timing of the improvement differed, the researchers found with the biggest improvement measured at 10pm associated with the once daily mid-afternoon dose.
The study also found all the groups had suppressed airway inflammation, assessed by eosinophil count, compared with baseline levels.
But inflammation was significantly lower at 10pm and 4am with the once daily mid-afternoon dose than it was with the twice daily dose.
It follows earlier research from the same team showing enhanced immune cell responsiveness to steroids in mid-afternoon.
Writing in Thorax, the researchers led by the University of Manchester, said it was the first study to show the importance of co-ordinating asthma treatment with circadian rhythms.
The findings need to be replicated in larger studies, but mid-afternoon dosing of inhaled beclomethasone ‘may lead to better clinical outcomes without increasing steroid-related morbidity or costs’, they concluded.
Study lead Dr Hannah Durrington, a clinician scientist at the University of Manchester and Manchester University NHS Foundation Trust, said: ‘Up to three-quarters of patients experience worsening symptoms overnight and up to 80% of fatal asthma attacks occur at night.
‘This study shows that aligning the timing of beclomethasone with the body clock could have significant impacts on treatment outcomes.
‘And this occurred without any of the associated adverse effects or costs of taking higher doses of steroids.
‘Our findings warrant further validation in a larger clinical trial to establish clinical feasibility in a real-life setting and to evaluate the health and economic impacts.’
An accompanying editorial said that the study offered promising insights into chronotherapy in these patients but it was also important to consider how well people would be able to comply with specific timings.
Dr Erika Kennington, head of research and innovation at Asthma and Lung UK, said: ‘A brilliantly simple piece of respiratory research shows that altering the time of day you take your preventer inhaler dose may have a huge impact on your medication’s effectiveness.
‘It’s incredible to think that something so easy as switching the timing of your inhaler dose to the afternoon, has the potential to improve your symptoms and ultimately could save your life.’
It comes as the UK drugs regulator has issued a warning to healthcare professionals not to prescribe salbutamol or terbutaline inhalers without an inhaled corticosteroid.
