chloroquine
Brand names: Aralen
Chloroquine phosphate is a drug used to treat and prevent malaria. It can also treat a type of infection called extraintestinal amebiasis.
Drug Pricing (NADAC)
Generic Price
$2.12/unit
Generic Available
Yes (5 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
This medicine can treat uncomplicated malaria caused by certain types of parasites.
Common side effects
No common side effects listed.
Key warnings
You should not take this medicine if you have changes in your retina or vision.
How It Works
Chloroquine phosphate works by killing the parasites that cause malaria and amebiasis. It stops the parasites from growing and multiplying in your body. For malaria caused by certain parasites, you may need to take another medicine with chloroquine.
How to Take It
Take chloroquine phosphate exactly as your doctor tells you. The dose depends on whether you are preventing or treating malaria or amebiasis. For malaria prevention, adults usually take 500 mg once a week, on the same day each week. Children's doses are based on weight. Continue taking it for 8 weeks after leaving the malaria area.
Pregnancy & Breastfeeding
Talk to your doctor if you are pregnant or breastfeeding before taking this medicine. It is not known if chloroquine can harm your unborn baby. Chloroquine can pass into breast milk.
Missed Dose
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule.
Storage
Store chloroquine phosphate tablets at room temperature (68-77°F) in a tightly closed, light-resistant container.
Side Effects (from patient reports)
Based on 432 FDA adverse event reports.
Serious Warnings
You should not take this medicine if you have changes in your retina or vision. You should not take this medicine if you are allergic to similar drugs.
Known Drug Interactions
7.4 Concomitant Use with Drugs that Induce Methemoglobinemia Concomitant use of ACZONE Gel, 7.5% with drugs that induce methemoglobinemia such as sulfonamides, acetaminophen, acetanilide, aniline dyes, benzocaine, chloroquine, dapsone, naphthalene, nitrates and nitrites, nitrofurantoin, nitroglycerin, nitroprusside, pamaquine, para‐aminosalicylic acid, phenacetin, phenobarbital, phenytoin, primaquine, and quinine may increase the risk for developing methemoglobinemia [see Warnings and Precautions ( 5.1 )] .
Mechanism: Both of these drugs can interfere with the way your red blood cells deliver oxygen to your body. Combining them increases the risk of a serious blood disorder.
What to do: Talk to your healthcare provider about the risks and watch for any unusual tiredness or trouble breathing.
( 7 ) 7.1 Drugs Prolonging QT Interval and Other Arrhythmogenic Drugs Hydroxychloroquine sulfate tablets prolongs the QT interval. There may be an increased risk of inducing ventricular arrhythmias if hydroxychloroquine sulfate tablets are used concomitantly with other arrhythmogenic drugs. Therefore, hydroxychloroquine sulfate tablets are not recommended in patients taking other drugs that have the potential to prolong the QT interval or are arrhythmogenic [see Warnings and Precautions (5.1) ].
Mechanism: Both of these drugs can change the electrical rhythm of your heart. Taking them together increases the risk of a dangerous irregular heartbeat.
What to do: This combination is not recommended. Talk to your doctor about using a different medication to avoid heart rhythm problems.
Drugs That May Cause Methemoglobinemia When Used with LIDODERM Patients who are administered local anesthetics are at increased risk of developing methemoglobinemia when concurrently exposed to the following drugs, which could include other local anesthetics: Examples of Drugs Associated with Methemoglobinemia : Class Examples Nitrates/Nitrites nitric oxide, nitroglycerin, nitroprusside, nitrous oxide Local anesthetics articaine, benzocaine, bupivacaine, lidocaine, mepivacaine, prilocaine, procaine, ropivacaine, tetracaine Antineoplastic agents cyclophosphamide, flutamide, hydroxyurea, ifos...
Mechanism: Both drugs can interfere with how your blood carries oxygen, which can lead to a dangerous health issue. Combining them makes this problem more likely to happen.
What to do: Use these drugs together only if your doctor says it is necessary and monitors you closely. Seek help immediately if your skin, lips, or fingernails look blue or gray.
7 DRUG INTERACTIONS 7.1 Effects of Other Drugs on VEKLURY Due to potential antagonism based on data from cell culture experiments, concomitant use of VEKLURY with chloroquine phosphate or hydroxychloroquine sulfate is not recommended [see Warnings and Precautions (5.3) and Microbiology (12.4) ].
Mechanism: Chloroquine can block the antiviral effects of remdesivir, making it less powerful at treating the virus. This interaction was discovered in laboratory tests.
What to do: You should not use these medications together. Your doctor will choose the most effective single treatment for your condition.
Examples of Drugs Associated with Methemoglobinemia: Class Examples Nitrates/Nitrites nitric oxide, nitroglycerin, nitroprusside, nitrous oxide Local anesthetics articaine, benzocaine, bupivacaine, lidocaine, mepivacaine, prilocaine, procaine, ropivacaine, tetracaine Antineoplastic agents cyclophosphamide, flutamide, hydroxyurea, isofamide, rasburicase Antibiotics dapsone, nitrofurantoin, para-aminosalicylic acid, sulfonamides Antimalarials chloroquine, primaquine Anticonvulsants phenobarbital, phenytoin, sodium valproate Other drugs acetaminophen, metoclopramide, quinine, sulfasalazine 7.6...
Mechanism: Chloroquine is known to cause a blood condition called methemoglobinemia, which makes it harder for your blood to carry oxygen. Taking it with other medications may increase the risk of this blood disorder.
What to do: Your doctor should monitor you for signs of low oxygen, such as blue-tinted skin or shortness of breath. They may need to perform blood tests to ensure your safety.
Common Questions
What strength does this medication come in?
Can I use this to treat complicated malaria?
Can I use this to prevent malaria if the parasite is resistant to chloroquine?
How long should I continue taking this medication after leaving an area where malaria is common?
What should I do if I experience vision problems while taking this medication?
Can I take this medication if I have a known allergy?
How often should I take this medication for malaria prevention?
What is the adult dose for treating uncomplicated malaria?
Can children take this medication?
Does this medication cure malaria?
Does chloroquine interact with other medications?
What drug class is chloroquine?
Is chloroquine safe during pregnancy?
Related Medications in Antimalarial
Other drugs grouped near chloroquine — same-class peers and common alternatives.
acyclovir
Zovirax
Acyclovir is an antiviral medicine.
Compare with chloroquine →
albendazole
Albenza
Albendazole is a medicine that fights parasites.
Compare with chloroquine →
amphotericin B
Ambisome, Fungizone
Amphotericin B liposome is an antifungal medicine.
Compare with chloroquine →
anidulafungin
Eraxis
Eraxis is an antifungal medicine.
Compare with chloroquine →
atovaquone/proguanil
Malarone
Malarone is a drug used to prevent and treat malaria.
Compare with chloroquine →
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What the FDA Data Shows for chloroquine
The FDA label for chloroquine (sold under brand names such as Aralen) classifies it as a prescription-only medication in the Antimalarial class. This medicine can treat uncomplicated malaria caused by certain types of parasites. Labeling covers dosing, contraindications, and monitoring requirements derived from clinical trials.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 432 voluntary reports. The database also lists 5 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated moderate severity. NADAC pricing from CMS shows a generic unit cost of $2.12.
Report counts do not establish causation — a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice — always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: October 1, 2024
Read our methodology — how this data is sourced, computed, and verified.
All federal data sources used on this page
- FDA Orange Book — approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed — NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) — post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm — standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files — federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database — current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages