People who may have the coronavirus should not be using NSAIDs (non-steroidal anti-inflammatory drugs) such as ibuprofen without talking to a doctor first, health officials are warning.
While the advice is just a precaution the World Health Organisation is suggesting people should self-medicate with paracetamol where possible.
WHO spokesman Christian Lindmeier told a press conference in Geneva that ibuprofen - commonly sold as Nurofen - is being investigated after reports it could make symptoms worse.
Lindmeier said while the reports were being investigated there were not any recent studies linking the popular over-the-counter drug with increased death rates.
However, he recommended people use paracetamol instead when self-medicating if possible.
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France's health minister had tweeted on Saturday that the drug could exacerbate symptoms.
"Taking anti-inflammatory drugs [ibuprofen, cortisone, ...] could be a factor in worsening the infection," he wrote. "If you have a fever, take paracetamol. If you are already on anti-inflammatory drugs or in doubt, ask your doctor for advice."
Despite an initial backlash to the minister's comments, the UK's NHS is also now advising people should not take ibuprofen if they suspect they have Covid-19.
Paul Little, Professor of Primary Care Research from the University of Southampton, said there was "sizeable literature" from studies in several countries that prolonged illness or the complications of respiratory infections may be more common when NSAIDS [non-steroidal anti-inflammatory drugs] are used.
Respiratory, septic and cardiovascular complications were all more common even when confounding factors were taken into account, Little said.
Paracetamol use was less likely to result in complications.
University of Reading virologist Professor Ian Jones said ibuprofen was an anti-inflammatory, meaning it dampened down the immune system which could slow the recovery process.
Studies into Sars - which is similar to the Covid-19 virus - found the virus reduced a key enzyme in the blood which could make pneumonia worse, and ibuprofen aggravated this effect.
However, the Francis Crick Institute's infection expert Dr Rupert Beale said while ibuprofen may make illness-related kidney damage worse, there wasn't any widely-accepted additional reason to avoid it for Covid-19 specifically.
Meanwhile Reuters has reported that two Geneva-based WHO employees have contracted the coronavirus. Hundreds of WHO staff are now working from home and press conferences are being carried out via social media, instead of having journalists in the room.