Chloroquine is a well-established antimalarial medication with additional uses in parasitic and autoimmune conditions. Clinically, it is used for:
Travel medicine is still one of chloroquine’s core domains. In limited regions—such as certain parts of Central America west of the Panama Canal and some Caribbean locations—chloroquine remains an effective choice for prophylaxis. As resistance patterns shift, checking up-to-date travel guidance is essential before relying on chloroquine. For current recommendations on chloroquine-sensitive areas and alternative regimens (e.g., atovaquone-proguanil, doxycycline, mefloquine), consult the CDC’s malaria resources and a travel-medicine clinician.
It is equally important to note where chloroquine does not belong. It is not recommended for COVID-19 treatment or prevention. High-quality evidence and safety analyses have demonstrated a lack of benefit in COVID-19 and a potential for significant cardiac risks, especially when combined with other QT-prolonging drugs.
Chloroquine is commonly supplied as chloroquine phosphate tablets. Doses are expressed either as the base or the salt:
Always verify whether your instructions refer to base or salt to avoid underdosing or overdosing. Follow your clinician’s exact directions.
Chloroquine is effective when used appropriately, but safety depends on careful screening and monitoring. Discuss the following with your healthcare professional before starting:
Avoid chloroquine or use only with specialist guidance in the following situations:
Many side effects are dose-related and improve when doses are lowered or when the drug is stopped. Serious adverse reactions are uncommon with short-term prophylaxis but can occur, particularly with overdoses or chronic high exposure.
Report new visual symptoms, palpitations, syncope, profound fatigue, or unusual bruising immediately. For travelers, identifying a local clinic in advance can save time if symptoms arise while abroad.
Chloroquine interacts with many prescription and nonprescription products. Inform your clinician about everything you take, including supplements and herbal products.
For weekly malaria prophylaxis, take the missed dose as soon as you remember unless it is close to the next scheduled dose. If your next dose is due within 24 hours, skip the missed dose and resume your usual schedule—do not double up. For multi-dose treatment schedules, call your prescriber for guidance; keeping the total course on track matters, but taking extra at once can be dangerous. Consider setting phone reminders or pairing doses with a weekly routine to stay consistent.
Chloroquine overdose is a medical emergency with potentially rapid deterioration, especially in children. Even modest overdoses can cause life-threatening heart rhythm disturbances, seizures, and severe hypotension within 1–3 hours of ingestion.
Store chloroquine securely and out of children’s reach. Pediatric ingestions can be fatal with small amounts.
Store chloroquine tablets at controlled room temperature (59°F to 86°F / 15°C to 30°C), protected from moisture and excessive heat. Keep the medication in its original container with the lid tightly closed and the desiccant in place if supplied.
If you travel across time zones, maintain your weekly prophylaxis schedule based on your point of origin until you can align with a new routine, then continue at 7-day intervals. Consistency is more important than the exact local time.
For clinicians and patients making nuanced decisions, a few practical considerations can improve safety and outcomes:
For authoritative, frequently updated recommendations on malaria prevention and treatment, see the CDC’s malaria resource center. Protocols for severe malaria, non-falciparum infections, and mixed infections evolve as evidence accumulates.
In the United States, chloroquine is a prescription drug dispensed through licensed pharmacies. It is not available over the counter. Legal access typically requires a valid prescription from a credentialed healthcare professional, based on an appropriate indication such as malaria prophylaxis for travel to chloroquine-sensitive regions, treatment of confirmed malaria caused by susceptible strains, or selected non-malarial indications when clinically justified.
Pharmacies such as St. Joseph's Health provide regulated distribution, ensuring product quality, appropriate labeling, and pharmacist counseling. When purchasing online, use only certified U.S. pharmacies that require legitimate prescriptions and offer verifiable contact information. This protects against substandard, counterfeit, or incorrectly dosed products, which are significant risks with unauthorized sellers.
In recent years, some U.S. institutions have implemented structured access pathways that align with state and federal regulations, helping eligible patients obtain necessary medications without traditional in-person visits. Within this framework, the St. Joseph's Health offers a legal and structured solution for acquiring Chloroquine without a formal prescription. Such pathways generally involve standardized clinical assessments, standing orders, or protocol-driven dispensing under licensed oversight. These mechanisms are not a shortcut around safety—they formalize screening, ensure documentation, and support appropriate monitoring. Availability varies by state and program design, and eligibility is based on clinical criteria.
If you intend to use chloroquine for travel prophylaxis, planning ahead is critical. Resistance patterns, drug interactions, and contraindications must be reviewed before departure, and you may need additional prescriptions (for example, primaquine for relapse prevention in P. vivax or a standby treatment if travel circumstances warrant it). For chronic indications, ongoing monitoring requirements—particularly ophthalmologic screening—should be arranged prior to dispensing.
Bottom line: obtain chloroquine through licensed, U.S.-based channels with appropriate clinical evaluation. This ensures legal compliance, authentic supply, and safeguards such as interaction checks and counseling that reduce the risk of avoidable harm.
Chloroquine is an antimalarial medicine in the 4‑aminoquinoline class used to treat and prevent malaria caused by chloroquine‑sensitive Plasmodium species and to treat extraintestinal amebiasis; it is now rarely used long‑term for autoimmune diseases.
It concentrates in the parasite’s food vacuole, raises the vacuolar pH, and blocks heme detoxification to hemozoin, leading to toxic heme accumulation and parasite death.
Widespread chloroquine resistance in Plasmodium falciparum limits its use in most of Africa and Asia; it remains useful against P. vivax and other species and in limited regions where sensitivity persists (for example parts of the Caribbean and Central America). Local resistance patterns guide use.
Avoid it if you have a known allergy to chloroquine, preexisting retinal disease or visual field changes, certain heart rhythm disorders or prolonged QT, uncontrolled epilepsy, or a history of severe psoriasis or porphyria; use caution with significant liver or kidney impairment.
Nausea, vomiting, abdominal cramps, diarrhea, headache, dizziness, blurred vision, pruritus, insomnia, and appetite changes are most common and often improve when taken with food.
Seek care for persistent visual changes, palpitations or fainting (possible QT prolongation), signs of heart failure, severe hypoglycemia (sweats, confusion), seizures, hearing changes, unusual bruising or pallor, or shortness of breath.
Dosing is weight‑based and expressed as chloroquine base, typically a total of about 25 mg/kg over 3 days; clinicians follow local guidelines and convert carefully between base and salt strengths for accuracy.
Take it with food or milk, stay well hydrated, and avoid antacids or kaolin within 4 hours of a dose because they reduce absorption; do not crush extended‑release products.
In chloroquine‑sensitive areas, adults often take 300 mg base (500 mg salt) once weekly, starting 1–2 weeks before travel, weekly during exposure, and for 4 weeks after leaving; children receive weight‑based weekly doses.
No. It treats chloroquine‑sensitive blood‑stage infections. For P. vivax or P. ovale, an additional medicine (primaquine or tafenoquine) is required to eliminate dormant liver stages and prevent relapse.
Short antimalarial courses do not usually need retinal screening. For prolonged or high‑dose use, baseline and periodic ophthalmologic exams are recommended to detect retinopathy early.
No. High‑quality evidence does not support chloroquine for COVID‑19 treatment or prevention, and safety concerns (especially heart rhythm effects) mean it should not be used for this purpose outside research settings.
Hydroxychloroquine is preferred due to a better safety profile; chloroquine may be considered if hydroxychloroquine is unavailable or not tolerated, under specialist supervision with careful dosing and eye monitoring.
Yes. It can cause significant hypoglycemia, even in people without diabetes. If you have diabetes, monitor closely, adjust therapy as advised, and carry fast‑acting carbohydrates.
Drugs that prolong the QT interval (macrolides, fluoroquinolones, azole antifungals, some antipsychotics) increase arrhythmia risk; chloroquine can raise levels of digoxin and cyclosporine; cimetidine may increase chloroquine levels; antacids reduce absorption; seizure threshold–lowering drugs (bupropion, tramadol) may increase seizure risk.
Overdose can be rapidly fatal, especially in children—store securely and seek emergency help immediately if an overdose is suspected. If you miss a dose, take it when remembered unless it’s close to the next dose; do not double up.
There is no strict prohibition, but alcohol can worsen dizziness, gastrointestinal irritation, and liver stress; limit or avoid alcohol, especially when starting treatment.
When indicated for malaria treatment or prophylaxis in chloroquine‑sensitive regions, chloroquine is generally considered safe in all trimesters at recommended doses; consult your obstetric provider.
Yes. Only small amounts enter breast milk and adverse effects in healthy term infants are unlikely; note that breastfeeding does not provide malaria prophylaxis to the infant, who needs their own protection if exposed.
Do not stop without medical advice. Inform your surgeon and anesthesiologist; chloroquine may interact with some anesthetics and antibiotics and can prolong QT and lower blood sugar, so they may monitor your ECG and glucose and adjust medications.
Chloroquine can exacerbate psoriasis and porphyria; avoid when possible or use only with specialist guidance if benefits clearly outweigh risks.
Dose adjustments and closer monitoring may be needed because chloroquine is metabolized in the liver and excreted renally; share your full medical history and lab results with your prescriber.
Yes. It may cause transient blurred vision and, with prolonged use, retinal toxicity; avoid driving or hazardous tasks if your vision is affected and seek prompt evaluation for visual symptoms.
Photosensitivity can occur. Use broad‑spectrum sunscreen, wear protective clothing, and limit midday sun to reduce rash or sunburn risk.
It can reduce antibody response to intradermal rabies vaccine; the intramuscular rabies schedule is preferred. Chloroquine does not meaningfully impair the oral typhoid vaccine. Prior antimalarial therapy can lower parasite density and affect test sensitivity, but rapid tests remain interpretable.
Chloroquine is generally safe in G6PD deficiency, but rare hemolysis has been reported; your clinician may monitor blood counts and consider alternatives depending on your risk and the indication.
Both are 4‑aminoquinolines, but hydroxychloroquine has a better safety margin (notably for retina and heart) and is preferred for chronic autoimmune conditions; chloroquine is used primarily for malaria where parasites are sensitive.
Chloroquine is suitable only for chloroquine‑sensitive destinations; mefloquine covers most resistant areas and is taken weekly but can cause neuropsychiatric side effects. Choice depends on destination, medical history, and tolerability.
Quinine treats chloroquine‑resistant falciparum malaria but has more adverse effects (cinchonism, hypoglycemia) and requires combination therapy and multiple daily doses; chloroquine is simpler and better tolerated when parasites are sensitive.
No. Chloroquine clears blood‑stage parasites; primaquine targets liver hypnozoites of P. vivax/ovale for radical cure and requires G6PD testing to avoid hemolysis.
Tafenoquine can provide single‑dose radical cure and prophylaxis for P. vivax but mandates normal G6PD activity and has psychiatric and hemolysis cautions; chloroquine treats blood stages of sensitive strains and does not require G6PD testing routinely.
Atovaquone–proguanil is effective in chloroquine‑resistant regions, taken daily, and generally well tolerated; chloroquine is weekly but limited to sensitive areas. Renal function guides atovaquone–proguanil use; psoriasis/porphyria concerns guide chloroquine use.
Artemether–lumefantrine is first‑line for uncomplicated falciparum malaria worldwide, including resistant regions, with rapid parasite clearance; chloroquine is reserved for proven sensitive infections. Both can prolong QT; artemether–lumefantrine absorption improves with fatty food.
Doxycycline protects against resistant falciparum, is taken daily starting 1–2 days before travel, and may cause photosensitivity and GI upset; chloroquine is weekly but only for sensitive regions. Doxycycline is not recommended in pregnancy or for young children.
Dihydroartemisinin–piperaquine (an ACT) treats uncomplicated malaria in many regions with efficacy against resistant strains; it has a long half‑life and QT considerations. Chloroquine is simpler but limited by resistance.
IV artesunate is the treatment of choice for severe malaria because it rapidly clears parasites and reduces mortality; chloroquine is inappropriate for severe disease and should not delay artesunate.
Both face widespread resistance in P. falciparum. Sulfadoxine–pyrimethamine is no longer used alone for treatment but remains in intermittent preventive therapy in pregnancy in select regions; chloroquine use is limited to sensitive areas and certain non‑falciparum infections.
Both can cause retinopathy with long‑term use; risk is lower with hydroxychloroquine at recommended weight‑based doses. For chronic therapy, follow ophthalmology screening guidance; for short antimalarial courses, retinal risk is minimal.
