chloroquine phosphate
Chloroquine works well to prevent and treat certain types of malaria. But it can cause serious side effects, such as heart rhythm problems.
What is Chloroquine?
What is Chloroquine used for?
Treatment of uncomplicated malaria
Prevention of malaria in areas of the world where there's no chloroquine resistance
Extraintestinal amebiasis (a type of parasitic infection)
How Chloroquine works
Chloroquine is an anti-malarial medication. It works by interfering with certain processes that the malaria-causing parasites need to grow.
Drug Facts
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What are the side effects of Chloroquine?
Common Side Effects
- Nausea
- Vomiting
- Diarrhea
- Stomach cramps
- Headache
- Rash
- Itching
Other Side Effects
- Tiredness
- Confusion
- Anxiety
- Hallucinations (hearing or seeing things that aren't there)
- Muscle weakness
Serious Side Effects
- Seizures
- Changes in vision: blurry vision, only seeing half of an object, difficulty focusing, trouble seeing things at night
- Irregular heartbeat (QT prolongation): dizziness, feeling lightheaded, blurry vision, pounding heart, fainting
- Dangerously low blood sugar: feeling anxious, sweating, shaking, confusion, dizziness, weakness, fast heartbeat, feeling hungry, coma
- Serious skin reactions: fever, tiredness, body aches, blistering rash, peeling skin
Source: DailyMed
The following side effects have also been reported
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
Incidence not known
attempts at killing oneself
back, leg, or stomach pains
black, tarry stools
bleeding gums
blistering, peeling, or loosening of the skin
blood in the urine or stools
blurred or decreased vision
change in near or distance vision
chest discomfort or pain
chills
cold sweats
confusion
continuing ringing or buzzing or other unexplained noise in the ears
dark urine
difficulty in focusing the eyes
difficulty with speaking
difficulty with swallowing
disturbed color perception
dizziness
dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
double vision
fast, slow, irregular, or pounding heartbeat
feeling that others are watching you or controlling your behavior
feeling that others can hear your thoughts
feeling, seeing, or hearing things that are not there
general tiredness and weakness
halos around lights
headache
hearing loss
inability to move the eyes
increased blinking or spasms of the eyelid
joint or muscle pain
large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
light-colored stools
loss of balance control
lower back or side pain
muscle trembling, jerking, or stiffness
muscular pain, tenderness, wasting, or weakness
night blindness
overbright appearance of lights
painful or difficult urination
pale skin
pinpoint red spots on the skin
puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
red skin lesions, often with a purple center
red, irritated eyes
restlessness
shuffling walk
sores, ulcers, or white spots on the lips or in the mouth
sticking out of the tongue
stiffness of the limbs
sweating
swollen or painful glands
tightness in the chest
trouble breathing
tunnel vision
twitching, twisting, or uncontrolled repetitive movements of the tongue, lips, face, arms, or legs
uncontrolled movements, especially of the face, neck, and back
unusual bleeding or bruising
unusual tiredness or weakness
upper right abdominal or stomach pain
vomiting
yellow eyes and skin
Get emergency help immediately if any of the following symptoms of overdose occur:
Symptoms of overdose
Cold, clammy skin
decreased urine
drowsiness
fast, weak pulse
increased thirst
lightheadedness, dizziness, or fainting
loss of appetite
muscle pain or cramps
numbness or tingling in the hands, feet, or lips
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Incidence not known
Change in hair color
increased sensitivity of the skin to sunlight
redness or other discoloration of the skin
severe sunburn
stomach cramps
trouble sleeping
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Pros and cons of Chloroquine
Pros
Generally safe to use for malaria prevention and treatment during pregnancy
Can be taken by children
Can take with or without food
Available as a lower-cost generic
Cons
Should be taken 2 weeks before traveling to an area with malaria, compared to some alternatives that can be taken 1-2 days before
Only works well against malaria from certain areas of the world
Can't treat severe malaria
Can worsen conditions, such as psoriasis or seizures
Pharmacist tips for Chloroquine
Make sure to take chloroquine according to the instructions given by your healthcare provider. If you're taking chloroquine for malaria prevention, you'll need to continue the medication even after you've left the area at risk for malaria.
If chloroquine upsets your stomach, taking it with food can help.
If you take an antacid (such as calcium carbonate (TUMS)), take it at least 4 hours apart from chloroquine because antacids can make this medication not work as well.
If you have high blood sugar and are taking medications that lower your blood sugar levels, such as insulin, let your provider know. Taking this type of medication at the same time as Chloroquine can raise your risk for experiencing dangerously low blood sugar. Your provider might ask you to check your blood sugar levels more often. Keep fast-acting sugars with you at all times so you can bring your blood sugar level back up to a safe range if needed. Symptoms of low blood sugar include shakiness, hunger, and feeling irritable.
It's best to avoid or limit the amount of alcohol you drink while taking chloroquine. Drinking alcohol with chloroquine can raise your chances of liver problems. If you drink alcohol regularly, let your provider know. They can help recommend an amount of alcohol that's safer to drink.
If you experience tremors (shaking) or uncontrollable movements while taking chloroquine, let your provider know right away. This might be a rare, but serious side effect of chloroquine.
Tell your provider if you have trouble hearing after starting chloroquine. This medication can cause damage to your ears and affect your hearing. Your provider might ask you to stop taking chloroquine if they think your hearing problem is caused by this medication.
Keep chloroquine up and away from children and pets. Small amounts have caused accidental deaths in children. If your child accidentally swallowed this medication and it's not prescribed to them, call a Poison Center right away at 1-800-222-1222.
Frequently asked questions about Chloroquine
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What are the risks and warnings for Chloroquine?
Chloroquine can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Heart problems
Risk factors: Taking other medications that affect heart rhythm | High doses | Existing heart condition
Some people have experienced serious heart problems, such as heart rhythm problems, when taking chloroquine. The risk is higher if you're taking higher doses of chloroquine or other medications that affect your heart rhythm. Let your provider know if you have heart problems because they might consider other medications for you. If you feel dizzy, lightheaded, or have blurry vision, get medical care right away. Your provider might ask you to stop taking chloroquine.
Low blood sugar
*Risk factors: Taking other medications that lower blood sugar *
Chloroquine can lower your blood sugar to dangerously low levels, which can be life-threatening. This can happen even if you're not taking other blood sugar medications.
Signs of low blood sugar include fast heartbeat, sweating, pale skin, shakiness, confusion, and irritability. You should carry some fast-acting sugar with you when you're taking chloroquine so you can raise your blood sugar whenever needed. Let your provider know if you experience low blood sugar while taking chloroquine because they might consider other medications for you.
Muscle weakness and nerve problems
Risk factors: Taking chloroquine for a long time
Some people reported muscle weakness while taking chloroquine. Your provider will test your muscle strength and reflexes for signs of weakness if you need to take this medication for a long time. If you notice weakness in your muscles, talk to your provider because they might ask you to stop taking chloroquine.
Worsening of psoriasis and porphyria
Hearing damage
Risk factors: History of hearing problems
Chloroquine can cause damage to your hearing, especially if you already have problems with your hearing. If you notice ringing in your ears or any changes in your hearing, stop taking chloroquine and talk to your provider right away.
Low blood counts
Risk factors: glucose-6-phosphate dehydrogenase (G6PD) deficiency
Chloroquine can affect blood counts. Your risk might be higher if you have a condition called G6PD deficiency. If you need to take this medication for a long period of time, your provider might order blood test to make sure your blood count is within a safe range.
Liver or kidney damage
Risk factors: Taking other medications that affect the liver | Alcoholism | Existing liver or kidney conditions
Chloroquine is processed in the liver and can potentially be harmful to the liver, especially if you have existing liver conditions. Drinking alcohol with this medication can also raise your chances of liver problems. Talk to your provider about these concerns.
Additionally, kidney damage has happened to some people who took chloroquine. If you're urinating less than usual or notice swelling in your body, let your provider know since these can be signs your kidneys aren't working well.
Seizures
Risk factors: History of epilepsy
Chloroquine might raise the risk of seizures in people who've experienced seizures in the past. Let your provider know if you've had past seizures because they might choose a different malaria medication for you.
Serious eye damage
Risk factors: Taking higher doses or chloroquine | Taking chloroquine for 5 years or longer | Kidney damage | Taking other medications that can cause vision problems | Eye problems
Though rare, chloroquine vision changes or eye damage. Your risk might be higher if you take chloroquine for 5 years or longer or if you have vision problems. Sometimes, vision changes can worsen even after stopping the medication. Your provider might ask you to get an eye exam before you start chloroquine. Let your provider know right away if you notice any changes to your vision because they might need to check your vision more often.
Chloroquine dosage forms
Typical dosing for Chloroquine
Malaria prevention
Ideally, your provider will have you start chloroquine 2 weeks before you travel to areas with malaria. Usually, you'll continue taking it while there and for 2 months after your return.
Adults: The typical dose is 500 mg by mouth weekly on the same day each week.
Children: Your child's provider will calculate the dose based on your child's body weight. It's typically given by mouth weekly on the same day each week.
If you're not able to start chloroquine 2 weeks before traveling, your provider will ask you take 2 doses of chloroquine (500 mg for adults and weight-based dose for children) 6 hours apart on the first day you start the medication.
Malaria treatment
Adults: The typical dose is 1 gram by mouth, followed by 500 mg 6 to 8 hours later. After that, you'll take 500 mg once daily for the next two days.
Children: Your child's provider will calculate the dose based on your child's body weight. Typically, your child will take a higher loading dose for their first dose. Then, they'll take a lower maintenance dose at 6 hours, 24 hours, and 36 hours after their loading dose.
If you have certain malaria parasites (P. vivax and P. ovale), your provider might also have you take another medication along with chloroquine to really get rid of the parasites.
Extraintestinal amebiasis
Adults: The typical dose is 1 gram by mouth daily for 2 days, then 500 mg daily for at least 2 to 3 weeks. Your provider might have you take another medication along with chloroquine.
Interactions between Chloroquine and other drugs
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
- Aurothioglucose
- Bepridil
- Cisapride
- Dronedarone
- Levomethadyl
- Mesoridazine
- Pimozide
- Piperaquine
- Saquinavir
- Sparfloxacin
- Terfenadine
- Thioridazine
- Ziprasidone
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Acarbose
- Acecainide
- Agalsidase Alfa
- Ajmaline
- Albiglutide
- Alfuzosin
- Alogliptin
- Amiodarone
- Amisulpride
- Amitriptyline
- Amoxapine
- Anagrelide
- Apomorphine
- Aprindine
- Aripiprazole
- Aripiprazole Lauroxil
- Arsenic Trioxide
- Asenapine
- Astemizole
- Atazanavir
- Azimilide
- Azithromycin
- Bedaquiline
- Bretylium
- Buprenorphine
- Buserelin
- Canagliflozin
- Carbamazepine
- Ceritinib
- Chloral Hydrate
- Chlorpromazine
- Chlorpropamide
- Cimetidine
- Citalopram
- Clarithromycin
- Clofazimine
- Clomipramine
- Clozapine
- Crizotinib
- Cyclobenzaprine
- Dabrafenib
- Dapagliflozin
- Dasatinib
- Degarelix
- Delamanid
- Desipramine
- Deslorelin
- Deutetrabenazine
- Dibenzepin
- Disopyramide
- Dofetilide
- Dolasetron
- Domperidone
- Donepezil
- Doxepin
- Droperidol
- Dulaglutide
- Ebastine
- Efavirenz
- Empagliflozin
- Encorafenib
- Enflurane
- Entrectinib
- Eribulin
- Erythromycin
- Escitalopram
- Exenatide
- Famotidine
- Felbamate
- Fingolimod
- Flecainide
- Fluconazole
- Fluoxetine
- Formoterol
- Foscarnet
- Fosphenytoin
- Fostemsavir
- Galantamine
- Gatifloxacin
- Gemifloxacin
- Glasdegib
- Glimepiride
- Glipizide
- Glyburide
- Gonadorelin
- Goserelin
- Granisetron
- Halofantrine
- Haloperidol
- Halothane
- Histrelin
- Hydroquinidine
- Hydroxychloroquine
- Hydroxyzine
- Ibutilide
- Iloperidone
- Imipramine
- Inotuzumab Ozogamicin
- Insulin
- Insulin Aspart, Recombinant
- Insulin Bovine
- Insulin Degludec
- Insulin Detemir
- Insulin Glulisine
- Insulin Lispro, Recombinant
- Isoflurane
- Isradipine
- Itraconazole
- Ivabradine
- Ivosidenib
- Ketoconazole
- Lapatinib
- Lefamulin
- Lenvatinib
- Levofloxacin
- Lidoflazine
- Linagliptin
- Liraglutide
- Lixisenatide
- Lofexidine
- Lopinavir
- Lumefantrine
- Macimorelin
- Mefloquine
- Metformin
- Methadone
- Methotrimeprazine
- Metronidazole
- Mifepristone
- Miglitol
- Mirtazapine
- Mizolastine
- Moricizine
- Moxifloxacin
- Nafarelin
- Nateglinide
- Nelfinavir
- Nilotinib
- Norfloxacin
- Nortriptyline
- Octreotide
- Ofloxacin
- Olanzapine
- Ondansetron
- Osilodrostat
- Osimertinib
- Oxaliplatin
- Ozanimod
- Paliperidone
- Panobinostat
- Papaverine
- Paroxetine
- Pasireotide
- Pazopanib
- Pentamidine
- Perphenazine
- Pimavanserin
- Pioglitazone
- Pirmenol
- Pitolisant
- Pixantrone
- Ponesimod
- Posaconazole
- Prajmaline
- Pramlintide
- Probucol
- Procainamide
- Prochlorperazine
- Promethazine
- Propafenone
- Protriptyline
- Quetiapine
- Quinidine
- Quinine
- Rabies Vaccine
- Ranolazine
- Remdesivir
- Repaglinide
- Ribociclib
- Risperidone
- Ritonavir
- Rosiglitazone
- Saxagliptin
- Selpercatinib
- Semaglutide
- Sematilide
- Sertindole
- Sertraline
- Sevoflurane
- Siponimod
- Sitagliptin
- Sodium Phosphate
- Sodium Phosphate, Dibasic
- Sodium Phosphate, Monobasic
- Solifenacin
- Sorafenib
- Sotalol
- Spiramycin
- Sulfamethoxazole
- Sulpiride
- Sultopride
- Sunitinib
- Tacrolimus
- Tamoxifen
- Tedisamil
- Telaprevir
- Telavancin
- Telithromycin
- Tetrabenazine
- Tolazamide
- Tolbutamide
- Toremifene
- Trazodone
- Triclabendazole
- Trifluoperazine
- Trimethoprim
- Trimipramine
- Triptorelin
- Vandetanib
- Vardenafil
- Vemurafenib
- Venlafaxine
- Vilanterol
- Vildagliptin
- Vinflunine
- Voclosporin
- Voriconazole
- Vorinostat
- Zolmitriptan
- Zotepine
- Zuclopenthixol
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Aluminum Carbonate, Basic
- Aluminum Hydroxide
- Aluminum Phosphate
- Ampicillin
- Calcium Carbonate
- Ciprofloxacin
- Cyclosporine
- Digoxin
- Dihydroxyaluminum Aminoacetate
- Dihydroxyaluminum Sodium Carbonate
- Kaolin
- Magaldrate
- Magnesium Carbonate
- Magnesium Hydroxide
- Magnesium Oxide
- Magnesium Trisilicate
- Praziquantel
- Sodium Bicarbonate
How much does Chloroquine cost?
Chloroquine contraindications
Current eye changes or problems
What are alternatives to Chloroquine?
Treatment of uncomplicated malaria
Prevention of malaria in areas of the world where there's no chloroquine resistance
Extraintestinal amebiasis (a type of parasitic infection)
Uncomplicated malaria in adults and children
Rheumatoid arthritis (RA) in adults
Systemic lupus erythematosus (SLE) in adults
Discoid lupus erythematosus (DLE) in adults
What is the latest news about Chloroquine?
Chloroquine images
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References
Best studies we foundAmneal Pharmaceuticals of New York LLC. (2022). CHLOROQUINE PHOSPHATE tablet [package insert]. DailyMed.
Centers for Disease Control and Prevention. (2022). Malaria.
Centers for Disease Control and Prevention. (2021). Malaria Information and Prophylaxis, by Country.
Centers for Disease Control and Prevention. (n.d.). Medicines for the Prevention of Malaria While Traveling Chloroquine (Aralen).
Centers for Disease Control and Prevention. (2021). Parasites - Amebiasis - Entamoeba histolytica Infection.
Centers for Disease Control and Prevention. (2023). Treatment of Malaria: Guidelines for Clinicians (United States).
Manivannan, E., et al. (2021). The rise and fall of Chloroquine/Hydroxychloroquine as compassionate therapy of COVID-19. Frontiers in Pharmacology.
MedlinePlus. (2022). Glucose-6-phosphate dehydrogenase deficiency.
MedlinePlus. (2020). Chloroquine.
Stokkermans, T. J., et al. (2023). Chloroquine and Hydroxychloroquine Toxicity. StatPearls.
U.S. Food and Drug Administration. (2020). FDA cautions against use of hydroxychloroquine or chloroquine for COVID-19 outside of the hospital setting or a clinical trial due to risk of heart rhythm problems.
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