Hydroxychloroquine trials halted amid safety fears

Patients and healthcare professionals are encouraged to report suspected side effects from hydroxychloroquine via the Yellow Card COVID-19 reporting site.

Laura Townsend
17 June 2020
Hydroxychloroquine AC384

There are emerging concerns about the use of hydroxychloroquine in COVID-19 patients.

The Medicines and Healthcare products Regulatory Agency (MHRA) has instructed UK clinical trials using hydroxychloroquine to treat or prevent COVID-19 to suspend the recruitment of further participants.


No new participants will be recruited to these trials until further data which justifies their continuation have been provided, and additional safety measures have been implemented.

This comes from advice from the Commission on Human Medicines, which met on 1 and 5 June 2020, after they reviewed the data that had been sent for each trial in response to MHRA requests.

This follows the emerging concerns about the use of hydroxychloroquine in COVID-19 and took into consideration the results from two different trials.

This includes the UK’s RECOVERY (Randomised Evaluation of COVid-19 thERapY) trial which has provided convincing evidence of no meaningful mortality benefit in hospitalised patients with COVID-19.


Report any suspected side effects.

Published only yesterday, preliminary results show Dexamethasone, an inexpensive steroid, can reduce the mortality rate of the COVID-19 presenting with severe respiratory complications.

Hydroxychloroquine and chloroquine are licensed in the UK to treat different health conditions such as malaria, rheumatoid arthritis, and lupus.

Dr. June Raine, MHRA’s CEO, said: “Neither hydroxychloroquine nor chloroquine are licensed to treat COVID-19 related symptoms or to prevent infection. It is important to note that patients taking hydroxychloroquine and chloroquine to treat other health conditions can continue to do so, as advised by their healthcare professional, as the balance of benefits and risks remains favourable in the licensed uses.”

The Yellow Card scheme is MHRA’s system of monitoring the safety of medicines and medical devices in the UK and it acts as an early warning system to identify new and strengthen existing safety information.


Patients or healthcare professionals can report any suspected side effects from hydroxychloroquine or chloroquine taken by patients with COVID-19 via the Yellow Card COVID-19 reporting site: coronavirus-yellowcard.mhra.gov.uk

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