Analysis: How drug used to treat ‘Delhi belly’ is among the six coronavirus treatments

·7-min read
Dexamethasone,   - Matthew Horwood/Getty Images Europe
Dexamethasone, - Matthew Horwood/Getty Images Europe

With the announcement yesterday that a £5 steroid could cut coronavirus deaths by a third in the sickest patients, hopes are growing that the disease may soon become manageable.

Dexamethasone, an anti-inflammatory drug usually used to treat conditions like arthritis or severe asthma and allergies, is the first that stops people dying and is being rolled out widely.

Scientists are excited not just because they have found a treatment that works, but because it raises the possibility that more drugs will soon be discovered that will save more lives, or - if given in combination - may cure Covid-19 entirely.

Scientists from the Recovery (Randomised Evaluation of Covid-19 therapy) trial - who released the dexamethasone results yesterday - have ongoing trials into four more treatments which could radically improve survival, including a drug usually used to treat Delhi Belly, or traveller's diarrhea.

Two more drugs are also showing promise. Here are the six drugs and treatments currently in British trials:


There are three ways to battle the virus: antivirals, anti-inflammatories or antibodies.

Antivirals prevent the virus from building to sufficient levels while anti-inflammatories stop the immune system from overreacting and mounting a lethal inflammatory response.

Antibodies are produced by the immune system to defend against an invader, and are boosted to high levels by a vaccine. But infusions of antibodies from recovered patients can also be used as a treatment to ramp up the body’s ability to fight a disease.

Lopinavir-Ritonavir is a combination of two antiviral drugs usually used to fight HIV. They work by inhibiting the enzymes required for the virus to replicate.

Trials have so far shown mixed results. A small study published in April of 86 patients at Guangzhou Eighth People’s Hospital, China, found the combination made no difference to the death rate or time to recovery.

But earlier tests on 199 patients at Jin Yin-Tan Hospital in China, showed those given the drug appeared to improve faster. Some experts believe it may help to give the treatment earlier.

When the Chinese results were released, Prof Ian Jones, Professor of Virology, University of Reading, said:. “Think bull in a china shop. If the bull is stopped as it leaves the shop the damage is already done but if it is stopped soon after entry, the damage is much reduced.”

Early in the outbreak, doctors in Thailand reported success in treating patients using a combination of HIV drugs alongside oseltamivir, a drug sold under the brand name Tamiflu to treat influenza.

Remdesivir, coronavirus trial, ebola drug, Gilead  - Ulrich Perrey/REUTERS
Remdesivir, coronavirus trial, ebola drug, Gilead - Ulrich Perrey/REUTERS


The broad-spectrum antiviral is currently undergoing clinical trials throughout the world, and is now being rolled out to seriously ill coronavirus patients in Britain to help speed up their recovery.

The drug works by disrupting the genetic code of a virus to prevent it replicating. Many viruses reproduce in a similar way so it is hoped the drug will be useful for several different infections and new diseases the emerge in the future.

Early data showing it can shorten the time to recovery by about 4 days and the Medicines and Healthcare products Regulatory Agency (MHRA) has cleared the treatment to be used as part of the Early Access to Medicines Scheme (EAMS).

Remdesivir was developed by pharmaceutical company Gilead more than a decade ago to cure an unknown ‘Disease X’ amid fears that a global pandemic was looming.

More than a dozen centres across the NHS have been trialling the treatment since April and results have been positive, but final results have not yet been released.


The commonly used antibiotic is widely used to treat chest, sinus, throat and skin infections, travellers' diarrhea - known as Delhi Belly - and sexually transmitted diseases.

The drug, which costs just 10 pence per day, is so important it is on the World Health Organisation’s (WHO) list of essential medicines which are the safest and most effective currently known.

Azithromycin prevents bacteria from growing by interfering with their ability to produce proteins and is often used as an alternative for patients who are allergic to penicillin.

But it can also stop inflammation and viral replication and is known to prevent the production of cytokines, which are important messengers for the immune system.

Many patients who die from coronavirus suffer a so-called ‘cytokine storm’ in which the body reacts so aggressively to the invader that it causes dangerous blood-clotting (thrombosis) in the lungs which prevents patients being able to breathe.

Immune cells rampage through the body beyond infected parts, damaging healthy tissues and preventing organs from getting enough blood. A rapid review by Oxford University which looked at three studies into using azithromycin for Covid-19 found mixed results. A small trial of 36 patients found those taking the antibiotic alongside hydroxychloroquine cleared the virus more quickly.

blood plasma donor, coronavirus treatment,  - Ben Stansall/AFP via Getty Images
blood plasma donor, coronavirus treatment, - Ben Stansall/AFP via Getty Images

Convalescent blood plasma

People who recover from coronavirus usually carry powerful antibodies which can fight off the virus and scientists are hopeful that transfusing them into sick people could boost the immune system.

The idea is not new. During the Spanish flu in 1918 pandemic, doctors used the blood serum from recovered flu patients to treat the sick successfully.

More recently, plasma transfusion was used experimentally to treat small numbers of people during the Sars outbreak of 2002 and 2003.

British hospital patients who have recovered from Covid-19 are being asked to donate their blood, and from this week, anyone who tests positive for the virus will also be asked to give blood.

In April, a small trial by Shanghai Jiao Tong University School of Medicine, in China, reported that 10 severely ill patients made a speedy recovery after being given blood plasma. One patient was able to come off ventilation just two days in an outcome dubbed ‘remarkable’ by the researchers.

The Food and Drug Administration (FDA) in the US has already approved the use of blood plasma therapy as an experimental treatment in clinical trials, and for critical patients without other options.British scientists are hoping to publish results from blood plasma trials in the coming weeks.


The drug suppresses the immune system, and again prevents the deadly cytokine storm which can prove fatal for patients.

It is usually used to treat disorders of the immune system, such as rheumatoid arthritis.

In April, trials on 129 patients in France showed the drug was able to ‘significantly’ decrease the number of deaths or life support interventions when compared to a control group.

Around 50 per cent of the trial participants received two tocilizumab injections and standard antibiotics therapy, while the control involved only standard treatment.

The study findings, which are yet to be published, were said to indicate clear ‘clinical benefit’ and results from the Oxford trial are likely to be released before the end of the summer.

hydroxychloroquine. president trump,  - George Frey/REUTERS
hydroxychloroquine. president trump, - George Frey/REUTERS


Trials into the antimalarial hydroxychloroquine were stopped by Oxford University recently after showing no benefit and possible harms.

It was hoped the drug would prevent the virus entering cells and small studies in France and China reported that patients who did not have severe symptoms recovered more quickly.

The drug was widely praised by Donald Trump who said he was taking it himself to ward off the virus.

However the Recovery trial released results on June 5 showing no clinical benefit for patients hospitalised with Covid-19.

Yet there are still trials ongoing to see whether giving the drug to people early could be beneficial.

Under the Principle (Platform Randomised trial of Interventions against COVID-19 in older people) trial carried out by Oxford University, older and vulnerable people with the disease will be given the medication to see if it can prevent them needing hospital treatment.

Chief Investigator, Chris Butler, Professor of Primary Care in the Nuffield Department of Primary Care Health Sciences: “As soon as we find that any one of the drugs in our trial is making a critical difference to people’s health, we want it to be part of clinical practice as soon as it can be introduced.”