Chloroquine: Uses, Risks, and What You Need to Know

When looking at chloroquine, a synthetic compound originally designed to combat malaria parasites. Also known as hydroxychloroquine, it has lingered in the medical conversation for decades because of its dual history in infectious disease and immune modulation.

Malaria remains a major global health challenge, especially in tropical regions. As an antimalarial drug, chloroquine targets the blood stage of the Plasmodium lifecycle, interrupting the parasite’s ability to digest hemoglobin. This mechanism made it a frontline treatment for many years until resistance spread. Understanding how chloroquine works against malaria helps explain why it was once a household name in travel medicine.

In early 2020, the world watched as COVID-19 surged. Researchers quickly repurposed existing drugs, and chloroquine entered the spotlight as a potential antiviral agent. Lab studies suggested it could raise endosomal pH and inhibit viral entry, but large‑scale clinical trials later showed limited benefit and notable safety concerns. The episode underscored how drug repurposing can spark hope, yet also demand rigorous evidence before widespread adoption.

Many people still confuse chloroquine with its cousin hydroxychloroquine. Chemically, hydroxychloroquine is a less toxic derivative, sharing a similar antimalarial core but adding a hydroxyl group that improves tolerability. Both drugs have been used for autoimmune conditions like lupus, but hydroxychloroquine generally carries a lower risk of heart rhythm disturbances. Knowing the distinction helps patients and clinicians avoid dosing errors and manage expectations around side effects.

Mechanistically, chloroquine accumulates in acidic cellular compartments, disrupting the function of lysosomes and the parasite’s digestive vacuole. This leads to a buildup of toxic metabolites and ultimately kills the organism. For patients, the therapeutic window is narrow; standard dosing ranges from 250 mg to 500 mg daily for short courses, but prolonged use can cause retinal toxicity, muscle weakness, or severe gastrointestinal upset. Regular eye exams are recommended for anyone on extended therapy to catch early signs of damage.

Drug interactions pose another layer of complexity. Chloroquine can amplify the effects of other QT‑prolonging agents, raising the risk of dangerous arrhythmias. It also interferes with the metabolism of certain antacids and statins, potentially altering their effectiveness. Before starting treatment, a thorough medication review is crucial to spot incompatibilities and adjust doses accordingly.

Today, chloroquine’s role is mostly limited to regions where Plasmodium vivax remains sensitive, and to specific rheumatologic indications where alternatives are unsuitable. Health agencies worldwide have issued clear guidelines: use chloroquine only when proven effective, monitor patients closely, and discontinue at the first sign of retinal changes. Ongoing research continues to examine its immunomodulatory properties, but any new application will need to balance potential benefits against the well‑documented safety profile.

Below you’ll find a curated selection of articles that dive deeper into drug comparisons, safety tips, and the latest research—all tied back to the themes we’ve covered here. Whether you’re curious about how chloroquine stacks up against newer antimalarials or want practical advice on managing side effects, the resources ahead will give you actionable insight. Let’s explore the collection together.