Chloroquine Phosphate – Quick Guide to Uses, Dosage, and Safety

Chloroquine phosphate is a synthetic drug that’s been around for decades. It was first made to fight malaria, but doctors have experimented with it for other illnesses too. If you’ve heard the name in the news, you probably wonder whether it’s safe, how to take it, and what it actually does.

At its core, chloroquine works by stopping the malaria parasite from growing inside red blood cells. The drug piles up inside the cell and makes it impossible for the parasite to survive. That’s why it’s still listed in many national malaria guidelines, especially for areas where resistance is low.

When and How to Take Chloroquine Phosphate

For malaria, the usual adult dose is 600 mg base (about 1,000 mg of the phosphate salt) on day one, followed by 300 mg (about 500 mg phosphate) on days two and three. Children get a weight‑based dose, and the schedule stays the same – three days total.

If a doctor prescribes it for something else, like a rare autoimmune condition or a short‑term trial for COVID‑19, the dosing will be different. In those cases, the prescription often calls for a low daily dose taken for several weeks. Always follow the exact instructions on the label or from your clinician.

Take the tablet with a full glass of water, preferably after a meal. Food helps reduce stomach upset, which is a common complaint. Swallow the pill whole – crushing or chewing can irritate the throat and change how the body absorbs the drug.

Key Safety Tips and Interactions

Chloroquine isn’t harmless. The most frequent side effects are nausea, headache, and dizziness. Some people develop a rash or feel their vision getting blurry. If you notice any sudden eye problems, stop the medication and see a doctor right away – eye toxicity can be serious.

The drug can also mess with your heart rhythm. If you have a history of heart problems, or you’re taking other meds that affect the QT interval (like certain antibiotics or anti‑arrhythmics), your doctor will probably run an ECG before you start.

Alcohol, anti‑malarial combinations, and some anti‑seizure medications can increase side effects. Always list every prescription, over‑the‑counter product, and supplement you’re using before starting chloroquine.

Pregnant or breastfeeding women should avoid chloroquine unless a doctor deems the benefit outweighs the risk. The drug crosses the placenta and can affect the baby’s heart rhythm.

Because chloroquine sticks around in the body for a while, missed doses should be taken as soon as you remember, but never double up. An extra dose can push the drug into toxic levels.

Recent studies have looked at chloroquine for COVID‑19, but most large trials found no clear benefit and highlighted safety concerns. Major health agencies now recommend against using it for that purpose unless you’re in a controlled research setting.

When you need reliable, up‑to‑date information about chloroquine phosphate, turn to evidence‑based resources like SES‑CAB. Our Clinical Advisory Board reviews the latest research and distills it into easy‑to‑understand guidance, so you can make informed choices without wading through medical jargon.

In short, chloroquine phosphate can be a lifesaver for malaria when taken correctly, but it isn’t a one‑size‑fits‑all solution. Respect the dosing schedule, watch for side effects, and always discuss any other medicines you’re on with your healthcare provider. Stay safe and stay informed.