Chloroquine and hydroxychloroquine are used in various places worldwide against the disease caused by the coronavirus. However, we do not yet know whether these drugs also work. In the Netherlands, therefore, a national investigation into these substances will start next week.

The old antimalarial drug chloroquine and the closely related hydroxychloroquine are currently sometimes used in Dutch hospitals in the treatment of patients with serious complaints due to the coronavirus.

The effect of these drugs on COVID-19 patients and the disadvantages of these drugs will be investigated in several places in the Netherlands starting next week. discussed this with Andy Hoepelman, professor of internal medicine and infectious diseases at UMC Utrecht and coordinator of this research.

Old anti-malarial and anti-rheumatic medicine

Hoepelman says that both chloroquine and hydroxychloroquine have been used for a long time. "Chloroquine has historically been used against malaria, and hydroxychloroquine is regularly prescribed for rheumatism and the autoimmune disease SLE (systemic lupus erythematosus)."

At present, both substances are included in the Dutch treatment guideline for COVID-19. Chloroquine and hydroxychloroquine may be used in hospitals to treat COVID-19, even though the effect has not yet been scientifically proven. This was chosen because there are indications that chloroquine and hydroxychloroquine may help and there is no agent with proven beneficial effect at all at COVID-19.

Research aimed at preventing worsening of symptoms

Hoepelman says that some small unpublished studies have been done in China on chloroquine and hydroxychloroquine and that the products have also been used in other places.

"The results seem mixed and in most studies there was no control group at all. A control group is a group of patients who do not receive the potentially active substance, but are otherwise treated in the same way. Without a control group, you cannot say whether treatment with chloroquine or hydroxychloroquine works better than standard hospital treatment. "

"We are now starting a study in the Netherlands in which COVID-19 patients, who are not in intensive care, but are admitted to hospital, either receive treatment with chloroquine, or treatment with hydroxychloroquine, or receive optimal standard treatment Such an investigation has not yet been conducted worldwide. "

"We want to know if patients treated with chloroquine or hydroxychloroquine are less likely to experience worsening symptoms of COVID-19 and whether these patients end up in IC less often than those who receive optimal standard treatment."



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Main side effect is on the heart

The possible side effects of chloroquine and hydroxychloroquine are also monitored in this study. "It does not help, it does not harm, does not apply to these drugs. Because chloroquine and hydroxychloroquine have long been used in other conditions, the side effects are known," said Hoepelman.

"The main side effect is a specific side effect on the heart. We pay attention to this and a heart film is made both before and during the treatment."

"In addition, there are some general side effects, such as nausea, vomiting, diarrhea and also psychological complaints. With long-term use, an eye condition can also develop. We do not expect this in this study because the patients only take chloroquine or hydroxychloroquine for five days."


Hoepelman hopes that after treating three hundred to four hundred patients, they can say whether chloroquine and hydroxychloroquine make COVID-19 worsen less often. "If it does seem to work, we can then look further into the best treatment."

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