How do you take Chloroquine (Chloroquine Phosphate)?

For malaria treatment in adults, the usual dose is 4 tablets (600mg base) on Day 1, then 2 tablets (300mg base) after 6-8 hours on the same day, then 2 tablets on Day 2, and 2 tablets on Day 3. Take with food or a glass of water to reduce stomach upset. Always complete the full course even if you start feeling better.

What are the side effects of Chloroquine (Chloroquine Phosphate)?

Headache, nausea or vomiting, stomach pain or loss of appetite, itching of the skin (this is very common among Nigerians taking chloroquine), blurry vision or dizziness

Who should not take Chloroquine (Chloroquine Phosphate)?

People who are allergic to chloroquine or have had a bad reaction to it before. People with existing eye or vision problems (especially retinal damage). People with epilepsy or a history of seizures. People with severe liver or kidney disease. People with certain heart conditions like long QT syndrome.

Prescription

Antimalarial

Chloroquine

Last reviewed July 2026

Who is this for?

For adults (18+). Standard adult dosing applies: see the How to Take tab for full instructions.

What is this drug?

Chloroquine is an antimalarial drug that works by killing the malaria parasite inside your red blood cells, stopping the infection from spreading in your body.

How it works

Inhibits Plasmodium parasite growth by accumulating in the parasite's digestive vacuole and intercalating into parasite DNA, disrupting nucleic acid synthesis and increasing local pH to toxic levels. Additionally, suppresses inflammatory responses by inhibiting toll-like receptor signaling and reducing pro-inflammatory cytokine production, making it effective in autoimmune conditions.

What is it used for?

Malaria treatment, malaria prevention (for travellers or people in malaria-prone areas), certain joint conditions like rheumatoid arthritis, lupus

Browse by condition

Malaria Arthritis & Joint Pain Rheumatoid Arthritis

Prescription Required

You need a doctor's prescription to buy this drug.

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What to watch out for

In Nigeria, chloroquine resistance is now very common. If your malaria does not improve within 2-3 days, go back to the hospital as you may need a different drug like ACTs (Artemisinin-based combination therapy). Do not buy chloroquine from roadside sellers or unregistered vendors as fake and expired drugs are common. The itching some Nigerians experience can be intense but is usually not dangerous, so do not stop the medication without talking to your pharmacist or doctor.

Common Side Effects

Headache
nausea or vomiting
stomach pain or loss of appetite
itching of the skin (this is very common among Nigerians taking chloroquine)
blurry vision or dizziness

Serious Side Effects

Severe eye problems or sudden changes in vision
as chloroquine can damage the eyes especially with long-term use. Hearing loss or ringing in the ears. Seizures (convulsions)
severe heart rhythm problems
or difficulty breathing: go to the hospital immediately if any of these happen.

Drug Interactions

Do not take chloroquine with antacids like magnesium hydroxide (Gestid, Andrews) at the same time, as they reduce how well chloroquine works; take them at least 4 hours apart. Be careful if you are taking heart drugs like digoxin, as chloroquine can increase its effects dangerously. Avoid drinking alcohol while on chloroquine as it can worsen dizziness and stomach upset.

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Pregnancy & Breastfeeding Warning

Chloroquine is generally considered safer than many other antimalarials during pregnancy, but you should always consult your doctor before taking it if you are pregnant or breastfeeding.

Who Should NOT Take This

People who are allergic to chloroquine or have had a bad reaction to it before. People with existing eye or vision problems (especially retinal damage). People with epilepsy or a history of seizures. People with severe liver or kidney disease. People with certain heart conditions like long QT syndrome.

How to Store

Store in a cool, dry place away from direct sunlight and heat. Nigerian weather can be very hot, so avoid storing near windows or in your car. Keep the container tightly closed and always keep it far away from children.

For information only: not medical advice. Always talk to a doctor or pharmacist before changing your medication.