MANILA — Almost four months since the COVID-19 virus was first identified in China, the world has yet to discover a cure or vaccine.

The World Health Organization said it’ll take at least one year to develop and distribute a vaccine.

• READ: Philippines told to prepare strategy as world seeks COVID-19 vaccine

In the meantime, medical experts have been using off-label drugs to treat severe and critical cases of COVID-19. Off-label drugs are medicine developed to treat other illnesses but are believed or have shown some evidence of effectivity against the novel coronavirus.

Some of these drugs have been included in the WHO’s Solidarity Trial, a multi-country clinical trial in search for a COVID-19 cure. The Philippines is among the more than 200 countries participating.

• READ: 500 PH patients to join WHO clinical trials on COVID-19 cure

Below are the list of experimental drugs being used to doctors in the Philippines and in other countries:

1. CHLOROQUINE AND HYDROXYCHLOROQUINE

Synthesized in 1934, Chloroquine became a major anti-malaria drug after World War II.

The WHO included the two closely-related drugs in its Solidarity Trial after small studies in China and France showed the “possible benefit of chloroquine phosphate against pneumonia caused by COVID-19.”

• READ: EXPLAINER: Why are malaria pills being used against coronavirus?

However, there have been a lot of negative news about the drug as they have been tied to several side effects, including heart rhythm issues.

• READ: What is chloroquine and could it cure the new coronavirus?

Countries like the United States and Canada have also issued warnings against its use without supervision of a physician.

• READ: Canada warns against chloroquine use as coronavirus treatment

Both are reportedly being used in Philippine hospitals but under close monitoring by doctors.

2. REMDESIVIR

Remdesivir is an antiviral drug administered intravenously. It was originally made to treat the deadly Ebola virus. In including it in the Solidarity Trial, the WHO cited promising animal studies using remdesivir for the Middle East Respiratory Syndrome (MERS-CoV) and the severe acute respiratory syndrome (SARS), two other strains of coronavirus.

The US National Institute of Allergy and Infectious Diseases said its trial involving 1,000 people showed that patients recovered faster using remdesivir.

• READ: Remdesivir: The COVID-19 drug helping patients recover faster

The drug has had mixed results though as a smaller study showed that it failed in curing COVID-19 patients.

• READ: Experimental virus drug remdesivir failed in human trial

3. LOPINAVIR/RITONAVIR

The drug combination of lopinavir and ritonavir is a licensed treatment for HIV. Like remdesivir, they have shown positive effects on MERS and SARS patients.

Anecdotal evidence of their effectivity against COVID-19 were recorded in Thailand.

• READ: Philippines to wait for proof Thai 'drug cocktail' effective vs coronavirus: DOH

“While there are indications from laboratory experiments that this combination may be effective against COVID-19, studies done so far in COVID-19 patients have been inconclusive,” WHO said, explaining the need to pursue further studies through the Solidarity Trial.

Although recent studies showed no effect on seriously ill patients.

• READ: A promising treatment for coronavirus fails

Lopinavir and ritonavir are included in the WHO’s list of essential medicines although some side effects include diarrhea, nausea, vomiting, and liver damage.

• READ: Desperate for coronavirus solutions, Chinese turn to HIV drugs, grey market and traditional cures

4. INTERFERON BETA

Interferon beta-1a is an injectable drug used to treat multiple sclerosis, a disease that severely affects the brain and the spinal cord or central nervous system.

Under the Solidarity Trial, interferon beta is administered with the drug combination of lopinavir and ritonavir.

A recently published study from Hong Kong showed that patients treated with the closely related interferon beta-1b, lopinavir/ritonavir plus the drug ribavirin, which is used to treat hepatitis, were able to recover faster from the COVID-19 illness.

The researchers also said the trio drug combination can reduce the quantity of viral shedding or when the virus is detectable and potentially transmissible.

Some patients were not initially given interferon beta-1b because of possible inflammation. However, the study showed that the groups that did not take interferon took longer to clear the virus, suggesting that interferon might be crucial in shortening the course of the illness.

• READ: Anti-viral drug trio found to shorten COVID-19 illness in mild cases: study

5. FAVIPIRAVIR

Just recently, the Philippines announced that it will run clinical trials on the anti-flu drug favipiravir, sold under the brand name Avigan.

Japan has promised to provide supplies to the Philippines and 40 other countries looking for COVID-19 treatment.

• Philippines to run anti-flu drug Avigan clinical trials on 100 COVID-19 patients

China has said it will include Avigan in its official list of drugs that are used to treat COVID-19 patients after clinical trials in Japan showed “encouraging results.”

• READ: PH gov’t asking Japan for allocation of ‘promising' anti-flu drug vs COVID-19

However, it is believed to be dangerous for pregnant women as it can cause birth defects.

6. TOCILIZUMAB

The immunosuppressive drug Tocilizumab, which has been used to treat rheumatoid arthritis, is included in the Philippine Society for Microbiology and Infectious Diseases’ (PSMID) guidelines for hospital care for COVID-19 patients.

The drug, which also goes by the brand name Actemra, is believed to help treat inflammation in patients with the coronavirus disease or those with severe immune system reactions called cytokine storms.

• READ: ‘Ang daming love from everyone’: Young MD who survived COVID-19 recalls struggle, then hope

Swiss drugmaker Roche hopes to finish its clinical trials on Actemra by May or June.

7. FAMOTIDINE

One study that has not yet been peer-reviewed reportedly shows the effectivity of heartburn medicine famotidine against COVID-19.

Famotidine is an active ingredient in the hearburn treatment Pepcid. The study found that those who took the drug had decreased risk of dying or being intubated. However, the researchers said it is still not clear why and that the findings “should not be interpreted to mean that famotidine improves outcomes in patients hospitalized with COVID-19.”

OTHER DRUGS

Other off-label drugs that are being studied are Sarilumab or Kevzara, which was developed for rheumatoid arthritis; Azithromycin, which has been used to treat various bacterial infections such as strep throat and pneumonia; Umifenovir or Arbidol, an antiviral treatment for influenza; Ciclesonide, an inhaled corticosteroid for asthma; Colchicine, a drug used to treat gout and is believed to help those with mild symptoms; Dipyridamole, a drug that inhibits blood clot formation; and even Sildenafil or Viagra, which has been used to treat erectile dysfunction and pulmonary arterial hypertension.