- Chloroquine (Aralen) vs. hydroxychloroquine (Plaquenil): What's the difference?
- What is Chloroquine? What is Hydroxychloroquine?
- What are the side effects of chloroquine and hydroxychloroquine?
- What is the dosage for chloroquine vs. hydroxychloroquine?
- What drugs interact with chloroquine and hydroxychloroquine?
- Are chloroquine and hydroxychloroquine safe to use while pregnant or breastfeeding?
Chloroquine (Aralen) vs. hydroxychloroquine (Plaquenil): What's the difference?
- Chloroquine (Aralen) and hydroxychloroquine (Plaquenil) are anti-malarial drugs used to treat several forms of malaria. Chloroquine and hydroxychloroquine are under investigation for treatment of the COVID-19 coronavirus disease. Study results on their effectiveness have been mixed.
- Chloroquine is also used to treat amebiasis that has spread outside of the intestines.
- Hydroxychloroquine is also used to treat lupus erythematosus and rheumatoid arthritis.
- Side effects of chloroquine and hydroxychloroquine that are similar include nausea.
- Side effects of chloroquine that are different from hydroxychloroquine include irreversible damage to the retina, deafness, tinnitus (ringing in the ears), reduced hearing, increased liver enzymes, loss of appetite, vomiting, and diarrhea.
- Side effects of hydroxychloroquine that are different from chloroquine include irritability, headache, weakness, hair lightening or hair loss, stomach upset, dizziness, muscle pain, and itching.
What is Chloroquine? What is Hydroxychloroquine?
Chloroquine (Aralen) is an anti-malarial drug useful in treating several forms of malaria as well as amebiasis that has spread outside of the intestines. It suppresses malaria infection, stops acute attacks, and lengthens the time between treatment and relapse.
It is similar to hydroxychloroquine (Plaquenil), and both drugs are under investigation for treatment of the COVID-19 coronavirus disease.
Its mechanism of action is unknown; however, malarial parasites invade human red blood cells, and chloroquine may prevent malarial parasites from breaking down (metabolizing) hemoglobin in human red blood cells. Chloroquine is effective against the malarial parasites Plasmodium vivax, P. malariae, P. ovale, and susceptible strains of P. falciparum.
Hydroxychloroquine (Plaquenil) is an anti-malarial drug used to treat several forms of malaria as well as lupus erythematosus and rheumatoid arthritis. It is similar to chloroquine (Aralen). Its mechanism of action is unknown. Malarial parasites invade human red blood cells. Hydroxychloroquine may prevent malarial parasites from breaking down (metabolizing) hemoglobin in human red blood cells.
Hydroxychloroquine is effective against the malarial parasites Plasmodium vivax, P. malariae, P. ovale, and susceptible strains of P. falciparum.
What are the side effects of chloroquine and hydroxychloroquine?
Common side effects include
- Irreversible damage to the retina
- Tinnitus (ringing in the ears)
- Reduced hearing
- Increased liver enzymes
Other, rare side effects include:
- Hair loss and bleaching of hair
Possible serious effects:
- Personality changes
- Extrapyramidal disorders
- Aplastic anemia
- Serious allergic reactions
- Muscle damage (myopathy)
- Maculopathy and macular degeneration
Other adverse reactions and side effects of Aralen
- There have been rare reports of severe skin reactions such as erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis, and exfoliative dermatitis.
- Chloroquine may precipitate a severe attack of psoriasis in patients with psoriasis and may worsen porphyria. Chloroquine should not be used in these conditions unless the benefit to the patient outweighs the potential risks.
- People with retinal or visual field changes should not use chloroquine unless it is absolutely necessary.
- Some strains of P. falciparum are resistant to chloroquine and hydroxychloroquine. Chloroquine resistance is widespread. Chloroquine should not be used for treatment of P. falciparum infections from areas of chloroquine resistance or malaria occurring in patients where chloroquine prophylaxis has failed. Patients infected with a resistant strains of plasmodia should be treated with another antimalarial drug.
- Retinopathy, maculopathy, irreversible retinal damage, as well as macular degeneration have been reported. Retinopathy from chloroquine may be dose related. Initial and periodic eye examinations are recommended during prolonged treatment. Chloroquine should be discontinued immediately if there are changes in vision.
- Chloroquine may cause acute extrapyramidal disorders (abnormal, uncontrollable body movements) that usually resolve after treatment is stopped.
- Patients should be observed for evidence of muscular weakness. If weakness occurs treatment should be stopped.
- Fatalities have occurred in children from accidental ingestion of small doses of chloroquine. Chloroquine should be kept out of the reach of children.
Side effects include
- hair lightening or loss,
- stomach upset,
- muscle pain,
- rash and
Rare but potentially serious eye toxicity can occur. This toxicity affects a part of the eye called the retina and can lead to color blindness and even loss of vision. An ophthalmologist (eye specialist) often can detect changes in the retina that suggest toxicity before serious damage occurs. Therefore, regular eye examinations, even when there are no symptoms, are mandatory.
Patients who are genetically deficient in a certain enzyme, called G6PD, can develop a severe anemia resulting from the rupture of red blood cells. This enzyme deficiency is more common in persons of African descent and can be evaluated by blood testing. Hydroxychloroquine may worsen psoriasis.
Latest Coronavirus News
Daily Health News
What is the dosage for chloroquine vs. hydroxychloroquine?
- For acute malaria attacks in adults the initial dose is 1 g followed by an additional 500 mg after 6 to 8 hours, then 500 mg 24 and 48 hours after the first dose.
- The dose for treating children is 10 mg/kg for the first dose then 5 mg/kg daily for 2 days, starting 6 hours after the first dose.
- The dose for treating intestinal amebiasis is 1 g daily for two days, followed by 500 mg daily for at least two to three weeks.
- Chloroquine usually is combined with an effective intestinal amebicide.
- The usual adult dose for treating malaria is 800 mg initially, followed by 400 mg 6-8 hours later and then 400 mg at 24 hours and 48 hours.
- The dose for malaria prevention is 400 mg every week starting 1 or 2 weeks before exposure and for 4 weeks after leaving the high risk area.
- The recommended adult dose for rheumatoid arthritis is 400-600 mg daily for 4-12 weeks followed by 200-400 mg daily.
- Systemic lupus erythematosus is treated with 400 mg once or twice daily for several weeks then 200-400 mg daily.
- Hydroxychloroquine should be taken with food or milk in order to reduce stomach upset.
What drugs interact with chloroquine and hydroxychloroquine?
- Antacids and kaolin can reduce absorption of chloroquine. Administration of this drug and these agents should be separated by at least 4 hours.
- Cimetidine (Tagamet) can block the breakdown of chloroquine, increasing its blood levels. This combination should be avoided.
- Chloroquine significantly reduces blood levels of ampicillin. Ingestion of ampicillin and chloroquine should be separated by at least two hours.
- Chloroquine may increase cyclosporine blood levels. Cyclosporine blood levels should be monitored and, if necessary, chloroquine should be stopped.
- Combining chloroquine and mefloquine may increase the risk of seizures.
- Chloroquine can reduce the antibody response to primary immunization with intradermal human diploid-cell rabies vaccine.
- Administration of hydroxychloroquine with penicillamine (Cuprimine, Depen) may increase penicillamine levels, increasing the risk of penicillamine side effects. The mechanism is unknown.
- Combining telbivudine (Tyzeka) and hydroxychloroquine may increase the risk of unexplained muscle pain, tenderness, or weakness because both drugs cause such side effects.
- Hydroxychloroquine suppresses the immune system and should not be combined with drugs that also suppress the immune system or live vaccines.
Are chloroquine and hydroxychloroquine safe to use while pregnant or breastfeeding?
There are no studies evaluating the safety and efficacy of chloroquine in during pregnancy. If you are pregnant this drug should be avoided unless it is necessary and the benefit outweighs the risk. Chloroquine is excreted in breast milk.
Hydroxychloroquine should only be used in pregnant women for malaria prophylaxis or treatment. Hydroxychloroquine may be secreted in breast milk and may cause side effects in the infant.
Subscribe to MedicineNet's General Health Newsletter
Chloroquine (Aralen) and hydroxychloroquine (Plaquenil) are anti-malarial drugs used to treat several forms of malaria. Chloroquine and hydroxychloroquine are under investigation for treatment of the COVID-19 coronavirus disease. Study results on their effectiveness have been mixed.
Multimedia: Slideshows, Images & Quizzes
What Is Lupus? Symptoms, Rash, and Treatment
What is Lupus? Learn about lupus symptoms like butterfly rash, joint pain and fatigue. Find causes, diagnosis, and treatments for...
Coronavirus COVID-19 (SARS-CoV-2): The Latest News, Updates and Information
See the latest news, updates, and information on the Coronavirus COVID-19 (SARS-CoV-2) outbreak. Learn about symptoms,...
Novel Coronavirus (COVID-19) Prevention Quiz
Why is coronavirus considered dangerous? What are the symptoms you should look for? Take this COVID-19 prevention quiz to learn...
Systemic Lupus Erythematosus Quiz: Test Your SLE IQ
This Lupus Quiz covers causes, signs, symptoms, facts, and treatments for this inflammatory autoimmune disease.
Coronavirus COVID-19 (SARS-CoV-2) Pandemic Outbreak: What You Need to Know
A new strain of coronavirus (COVID-19, SARS-CoV-2) was reported from Wuhan, China in December, 2019. This outbreak of respiratory...
Picture of Systemic Lupus Erythematosus 1
A chronic inflammatory condition caused by an autoimmune disease. See a picture of Systemic Lupus Erythematosus (SLE) and learn...
Picture of Lupus
A chronic inflammatory condition caused by an autoimmune disease. See a picture of Lupus Rash and learn more about the health...
Picture of Systemic Lupus Erythematosus 2
Erythematous, edematous plaques appear in a "butterfly" distribution on the face. See a picture of Systemic Lupus Erythematosus...
Picture of Acute Systemic Lupus
Acute systemic lupus erythematosus. See a picture of Acute Systemic Lupus and learn more about the health topic.
Related Disease Conditions
16 Early Rheumatoid Arthritis (RA) Signs & Symptoms
Early rheumatoid arthritis (RA) symptoms and signs vary differently from person to person. The most common body parts that are initially affected by RA include the small joints of the hands, wrists, and feet, and the knees and hip joints. Joint inflammation causes stiffness. Warmth, redness, and pain may vary in degree.
Rheumatoid Arthritis (RA)
Rheumatoid arthritis (RA) is an autoimmune disease that causes chronic inflammation of the joints, the tissue around the joints, as well as other organs in the body. Early RA signs and symptoms include anemia, both sides of the body affected (symmetric), depression, fatigue, fever, joint deformity, joint pain, joint redness, joint stiffness, joint swelling, joint tenderness, joint warmth, limping, loss of joint function, loss of joint range of motion, and polyarthritis.
Lupus (Systemic Lupus Erythematosus or SLE)
Systemic lupus erythematosus is a condition characterized by chronic inflammation of body tissues caused by autoimmune disease. Lupus can cause disease of the skin, heart, lungs, kidneys, joints, and nervous system. When only the skin is involved, the condition is called discoid lupus. When internal organs are involved, the condition is called systemic lupus erythematosus (SLE).
Second Source article from WebMD
Pain Management and Rheumatoid Arthritis
Second Source article from WebMD
Second Source article from Government
Second Source article from Government
Rheumatoid Arthritis vs. Fibromyalgia
Though rheumatoid arthritis (RA) and fibromyalgia have similar symptoms, RA is an autoimmune disease and fibromyalgia is a chronic pain syndrome. RA symptoms include joint redness, swelling, and pain that lasts more than 6 weeks. Fibromyalgia symptoms include widespread pain, tingling feet or hands, depression, and bowel irritability. Home remedies for both include stress reduction, exercise, and getting enough sleep.
Malaria is a disease that is spread by the bite of an infected Anopheles mosquito. Malaria symptoms include fever, chills, nausea, vomiting, and body aches. Treatment involves supportive care and antibiotics.
COVID-19 vs. Flu vs. Cold
When you're feeling sick, it can be difficult to distinguish the symptoms of a COVID-19 infection from the symptoms of the common cold or the flu (influenza). While fever is common with the flu and COVID-19, sneezing is typically only associated with colds. Though sore throats are typical with colds, they are uncommon with COVID-19 infections and the flu.
COVID-19 (Coronavirus, 2019-nCoV)
Infection with COVID-19 (2019 novel coronavirus, 2019-nCoV) causes respiratory problems in humans. Transmission of COVID-19 occurs mainly through contact with respiratory sections from an infected person, however, fecal contamination may also spread the virus. Symptoms start off flu-like and progress to coughing, fever, shortness of breath, shaking chills, headache, loss of sense of taste and/or smell, muscle pain, and sore throat. Treatment focuses on supportive care and symptom relief. COVID-19 vaccines are available.
Rheumatoid Arthritis vs. Arthritis
Arthritis is a general term used to describe joint disease. Rheumatoid arthritis (RA) is a type of arthritis in which the body’s immune system mistakenly attacks the joints, causing chronic inflammation.
Is Malaria Contagious?
Malaria is transmitted via the bite of an infected mosquito. The incubation period for malaria depends upon the species of Plasmodium that the infected mosquito transmits to the individual. Symptoms include high fever, chills, sweating, headaches, vomiting, and nausea.
Juvenile Rheumatoid Arthritis (JRA)
Juvenile rheumatoid arthritis (JRA) annually affects one child in every thousand. There are six types of JRA. Treatment of juvenile arthritis depends upon the type the child has and should focus on treating the symptoms that manifest.
Osteoarthritis vs. Rheumatoid Arthritis
Osteoarthritis (OA) and rheumatoid arthritis (RA) are chronic joint disorders. RA is also an autoimmune disease. OA and RA symptoms and signs include joint pain, warmth, and tenderness. Over-the-counter pain relievers treat both diseases. There are several prescription medications that treat RA.
Is Lupus Contagious?
Systemic lupus erythematosus in an inflammatory disease. Symptoms and signs include joint pain, fever, and rash. Though lupus is incurable, early medical intervention can help to reduce inflammation and protect the affected individual's organs.
COVID-19 (Coronavirus) Prevention Tips
COVID-19 is a novel coronavirus that spreads from person to person via infected respiratory droplets. The main symptoms of COVID-19 infection include cough, fever, and shortness of breath. Occasionally, people infected with COVID-19 may experience diarrhea, a sore throat, a runny or stuffy nose, or aches and pains. Avoiding contact with infected people, social distancing, not touching your face, frequent hand washing, cleaning, and disinfecting of frequently touched surfaces can help to reduce your risk of contracting the 2019 novel coronavirus.
Treatment & Diagnosis
- Systemic Lupus Erythematosus FAQs
- Wuhan Coronavirus FAQs
- How Long Will it Take to Recover from Malaria?
- Can Malaria Kill You? Can You Survive Malaria?
- What Is the Best Medicine for Malaria Treatment?
- Early Malaria Vaccine Tests
- Is It Safe to Travel to Malaria Risk Areas During Pregnancy?
- What Are Side Effects of Antimalarial Drugs While Breastfeeding?
- Does Discoid Lupus Cause Enlarged Spleen?
- Can Lupus Cause Hip Pain?
- Are Lupus and Psychosis Connected?
- Can UCTD Turn into Lupus?
- Malaria Symptoms and Signs
Medications & Supplements
Prevention & Wellness
- WHO Halts Testing of Drug That President Trump Has Embraced
- Trump Taking Drug Discredited as Safe or Effective Against Coronavirus
- Chloroquine COVID-19 Trial Halted After Patient Deaths
- Coping With Cancer During the COVID-19 Pandemic
- COVID-19 Guidelines for Evaluating and Testing Coronavirus Patients
- Aralen, Plaquenil Shortages From COVID-19 Threaten Lupus, RA Patients
- Can Doctors Work Across State Lines During Coronavirus Crisis?
- Coronavirus on Social Media: COVID-19 Hashtags, Social Distancing, Twitter Tweets
- Could COVID-19 Survivors' Blood Help Save Very Ill Patients?
- Blood Type May Affect COVID-19 Risk
- Another Study Finds COVID-19 Typically Mild for Kids
- Babies Are Spared Severe COVID-19 Symptoms
- Can U.S. Hospitals Handle Coronavirus (COVID-19)?
- Chickens Make Malaria Mosquitoes Fly the Coop
- Combo Treatment Protects Pregnant Women, Fetuses From Malaria in Study
- Did Malaria, Bone Disease Kill King Tut?
Health Solutions From Our Sponsors
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.