Chloroquine also known as chloroquine phosphate is an anti-malarial drug that is available by prescriptions only. It was first approved by the FDA since 1949 for medical use and is sold both as brand and generic names at 500mg and 250mg. The brand name that you can find in the market is an expensive drug compared to its generic counterpart. Aside from its anti-malarial properties, this drug is also used to treat liver infections caused by protozoa or extraintestinal amebiasis. The mechanism of action of chloroquine against a malarial parasite is not well understood but it is believed that this drug inhibits malarial parasite from invading the human red blood cells and preventing it from breaking the hemoglobin in the red blood cells.
Recent in vitro studies have shown that chloroquine has antiviral properties against SARS-CoV2, the virus that causes COVID-19 pandemic. SARS-CoV2, the virus that causes coronavirus disease 2019 or COVID-19 is spreading rapidly and scientists around the world are endeavoring to discover drugs that would combat the disease.
What is COVID-19?
COVID-19 or coronavirus 2019 is an infectious respiratory disease that can spread from person to person through viral droplets as a result of coughing and sneezing by an infected person or touching infected surfaces. This disease emerged in the city of Wuhan, China but the exact source of the virus remains unknown. The first infections were linked to a live animal market but the virus is now spreading from person to person.
COVID-19 is a new disease caused by the new strain of coronavirus that has not previously been seen in humans. The virus that causes COVID-19 is not the same as the coronaviruses that commonly spread among humans and causes mild illnesses such as common colds.
Who are at high risk of developing severe illness?
Since it’s a new disease there is limited information regarding the risk factors for severe diseases. Based on the current data available and clinical expertise from medical professionals around the world, those who are at high risk for severe illness from coronavirus are:
Can Chloroquine be a game-changer?
At this time there is no FDA-approved medication yet available to treat coronavirus disease 2019. There is no vaccine too to prevent the spread of this disease. Though the development of vaccines is underway, any approved and effective vaccine is at least 12-18 months away.
In desperate hopes of finding a cure, medical researchers and regulators everywhere are working very hard to get through the process of testing and approvals in search for something that can at least reduce the severity and duration of COVID-19 symptoms. Many doctors are conducting clinical trials involving the use of four existing drugs, one of which is the Chloroquine, as a potential treatment against the new coronavirus responsible for the current pandemic. The Food and Drug Administration is also working with vaccine developers, researchers and manufacturers to expedite the development and availability of medical products such as antibodies, vaccines, and drugs to prevent coronavirus disease.
Antiviral effects of Chloroquine
Previous studies have shown that this drug had a wide range of antiviral effects. Chloroquine was first looked by researchers during the severe acute respiratory syndrome outbreak in 2002-2003, a coronavirus with substantial similarities to COVID-19. A study in Virology journal in 2005 found that this drug inhibits the virus in primate cells after infections. Chloroquine was also found to inhibit SARS infection before exposure which successfully reduces the viral load.
The interest in using Chloroquine as a potential treatment for COVID-19 was reignited by Chinese researchers suggesting that it had “potent efficacy” against pneumonia due to the SARS-CoV2 but no data yet has been shared with the World Health Organization. However, the interest in using Chloroquine is serious enough that the World Health Organization has identified Chloroquine as one of the four potential drugs to include in the global trial known as Solidarity.
How Chloroquine works
The way chloroquine works against microparasite that causes malaria is different from the way it works against SARS-CoV2. Although the exact mechanism of action by which chloroquine works against the virus remains unclear, scientists believed that chloroquine disrupts the ability of the virus to enter a cell. Chloroquine raises the pH level of endosomes inside the cells that are hijacked by the virus. This prevents the fusion and stops the virus from entering the cells. Chloroquine also blocks the enzyme involved in the fusion between the receptor cells and the virus thus preventing the viral replication process.
Warning and Precautions when taking Chloroquine