An inhaled, widely available, asthma drug shortens recovery time in people with coronavirus who have not been admitted to hospital, a new study suggests.

British patients will be able to access the first ever at-home Covid-19 treatment after the NHS approved budesonide for use on a “case-by-case” basis among older adults in the community, which means that GPs will be able to prescribe it to their patients.

Researchers say the discovery is a “significant milestone” for the pandemic, and that the drug, budesonide, is effective as a treatment at home and during the early stages of the illness.

Early treatment with the medication shortens recovery time by a median average of three days in those with Covid-19 who are at higher risk of more severe illness and are treated in the community, according to the research.

It is a safe, costs around £14 for an inhaler, and readily available corticosteroid commonly used around the world in inhalers to treat asthma and chronic obstructive pulmonary disease.

Budesonide was added to the Oxford University’s Platform Randomised Trial of Interventions against Covid-19 in Older People (Principle) trial in November last year.

Experts suggest that medical practitioners around the world may wish to consider the results of the study when making treatment decisions.

This is a significant milestone for this pandemic and a major achievement for community-based research

Joint chief investigator Professor Richard Hobbs, head of Oxford University’s Nuffield Department of Primary Care Health Sciences, said: “For the first time, we have high-quality evidence of an effective treatment that can be rolled out across the community for people who are at most risk of developing more severe illness from Covid-19.

“Unlike other proven treatments, budesonide is effective as a treatment at home and during the early stages of the illness.

“This is a significant milestone for this pandemic and a major achievement for community-based research.”

For the interim report, a total of 961 patients were randomly assigned to receive inhaled budesonide at home.

They were compared with 1,819 patients randomly assigned to the usual standard of NHS care alone.

Of these, 751 people in the budesonide group and 1,028 in the usual care group had the virus and were included in the primary interim analysis.

Based on the interim analysis using the data from March 25, the study found the estimated median time to self-reported recovery for inhaled budesonide was 3.011 days shorter compared with usual care.

The research, which has not yet been peer-reviewed, suggests there is a high probability (0.999) of the treatment being superior to the usual standard of care.

According to the findings, 32% of those taking inhaled budesonide, compared with 22% in the usual care group, recovered within the first 14 days since being randomised into the trial and subsequently have remained well until 28 days.

Participants in the budesonide group also reported greater wellbeing after two weeks, researchers found.

Among patients who had completed all 28 days of study follow-up, 8.5% (59/692) in the budesonide group were admitted to hospital with Covid-19 compared with 10.3% (100/968) in the usual care group.

Researchers say that since fewer people than expected were admitted to hospital in the trial, and with cases and admissions to hospital continuing to drop in the UK, the interim analysis – published as a pre-print – cannot suggest whether budesonide reduces hospital admissions.

Patients with coronavirus symptoms which started within 14 days and who are at higher risk of a poor outcome from the illness could join the trial, and those who tested positive were included in the main analysis.

Those treated with inhaled budesonide were asked to inhale 800 micrograms twice a day for 14 days and were followed up for 28 days.

All patients were over the age of 50 with an underlying health condition which put them at more risk of serious Covid-19 illness, or were over 65.

We are delighted to see these trial results for a medicine that could help people with Covid-19 recover more quickly at home instead of being admitted to hospital

As soon as all remaining patients in the trial have completed their follow-up and a full analysis has been completed, detailed results on time to recovery and hospital admissions will be published.

For this preliminary report, 92.8% of people randomised to the budesonide arm had the opportunity to complete 28 days of follow-up.

Associate Professor Gail Hayward, Principle trial co-principal investigator, Nuffield Department of Primary Care Health Sciences, said: “Personally, I think this does have significant implications, because this is the first time a treatment has been shown to be beneficial for patients in the community.”

Professor Stephen Powis, NHS England National Medical Director, said: “We are delighted to see these trial results for a medicine that could help people with Covid-19 recover more quickly at home instead of being admitted to hospital.”

On Monday, the NHS issued an alert to GPs and prescribers setting out that inhaled budesonide is not currently being recommended as standard of care, “but can be considered (off-label) on a case-by-case basis for symptomatic Covid-19 positive patients aged 65 and over, or aged 50 or over with co-morbidities”.

Professor Chris Butler, joint chief investigator of the Principle trial, University of Oxford, said: “It is encouraging to see that the NHS has announced that it now permits off-label use for inhaled budesonide in primary care on a case-by-case basis following the results from the Principle trial.

“We all look forward to the full findings from the trial and any further recommendations on ways GPs can treat Covid-19 patients in their homes.”