Hydroxychloroquine (Oral)

Hydroxychloroquine is used to treat health conditions that are caused by protozoan parasites, including malaria. The drug is also used to treat some of the symptoms caused by arthritis and lupus erythematosus.


In the US, hydroxychloroquine is better known by its brand name, Plaquenil. It is a prescription only drug and comes in the form of tablets for oral use. The medicine can be used alone or in combination with one or more other drugs.

Hydroxychloroquine is one of a group of medications called antiprotozoals and is also classed as a disease-modifying anti-rheumatic drug. Protozoa are tiny, one-celled parasitic animals that can cause infections in the body. This drug is primarily used to treat malaria, a debilitating disease transmitted through mosquito bites. It is also effective in tackling protozoan conditions of the liver. The medication is also used to treat some of the symptoms of some autoimmune diseases such as rheumatoid arthritis and lupus erythematosus, including joint inflammation, pain, swelling, and stiffness.

It should be noted that hydroxychloroquine is not effective in treating chloroquine resistant strains of malaria. If you are due to travel to areas where malaria is present, ask your doctor for guidance on the correct anti-malarial drugs to use.

Conditions treated

  • Protozoan bacterial diseases, including certain strains of malaria
  • Certain autoimmune diseases, including lupus erythematosus and rheumatoid arthritis

Type of medicine

  • Antiprotozoal
  • Disease-modifying anti-rheumatic
  • Tablet

Side effects

In addition to the effects it is designed to have, hydroxychloroquine can cause some unexpected and unwanted side effects in some patients. You may not notice anything untoward when you start taking hydroxychloroquine, but if you do, you may need to seek further medical attention. Long-term use or high doses of hydroxychloroquine can cause serious side effects.

You should check with your GP if you notice any of the side effects that are noted in the list below:

  • Weakness
  • Feeling unusually tired
  • Experiencing unusual bruising or bleeding
  • Fever and sore throat
  • Buzzing or ringing in ears hearing loss
  • Mental or mood changes
  • Increased muscle weakness
  • Increased feelings of excitability
  • Headaches
  • Drowsiness
  • Convulsions (seizures)
  • Blurred vision or other altered vision, potentially worsening after the medication is stopped

Hydroxychloroquine can cause a few effects that do not generally need more medical attention. The effects usually disappear during treatment as the body gets used to the medication. In addition, your GP may be able to suggest ideas on how you can reduce or prevent some of the side effects. Speak to your doctor if these effects do not resolve within a week or so of you starting to take hydroxychloroquine.

  • Stomach pain or cramps
  • Skin rashes
  • Poor appetite
  • Nausea or vomiting
  • Itching (more commonly seen in black patients)
  • Increased hair loss or bleaching
  • Headaches
  • Feeling nervous or restless
  • Dizziness or lightheadedness
  • Difficulty in seeing to read
  • Diarrhea
  • Blue-black discoloration of fingernails, skin, or inside of mouth

There are some side effects that may be caused by hydroxychloroquine that do not occur in all patients. If you experience anything else that is not listed here, check with your GP.


It is a good idea to take your hydroxychloroquine tablets with a glass of milk or with a meal, to reduce the risk of an upset stomach, unless you are instructed otherwise by your GP.

You must keep hydroxychloroquine where it cannot be easily accessed by small children. Children have acute sensitivity to hydroxychloroquine, and an overdose can be extremely dangerous, with fatalities having been recorded in juveniles who have taken just a few tablets.

You must take hydroxychloroquine precisely as directed by your GP. Do not exceed or reduce the prescribed dose, and do not extend the course of treatment. If you do, you may increase the likelihood of a bad reaction to the drug.

If you have been given hydroxychloroquine to prevent you from contracting malaria, you must continue to take it for the full course of treatment. If you are already suffering from malaria, keep taking the tablets for the whole course, even if you feel better within a few days. Completing the course will ensure that the infection is completely resolved. If you abandon treatment too early, the disease could return.

This medication is most effective when taken regularly. Take your medicine at the same time, on the same day, evenly spaced. You must not omit any of your prescribed doses. If you forget to take a tablet, do not double the dose; take the omitted tablet immediately, and then resume your prescribed schedule.

For the prevention of malaria:

You may need to commence your hydroxychloroquine tablets one or two weeks prior to travelling to a location that malaria is prevalent in. This gives your GP sufficient time to source a different medication if you have a bad reaction to hydroxychloroquine.

You will need to continue taking hydroxychloroquine for the duration of your time in the affected location and for at least four to six weeks following your departure from it. Note that no medication can give you complete protection against malarial infection. However, to give yourself the most effective protection, you must take the full course of hydroxychloroquine as directed by your GP. If you develop a fever while you are traveling or within a couple of months following your return, you must speak with your GP right away.

For the treatment of lupus or rheumatoid arthritis:

You will need to take hydroxychloroquine for a while to notice any difference in your symptoms, and it could take six months before the full benefits of the drug are noticed.

If you are cannot take tablets, ask your pharmacist to crush them for you and place the powder into capsules for you instead. You can then mix the resultant powder with a small amount of jelly, jam, or jello. Make sure that you eat it all so that you take the total amount of hydroxychloroquine.

Dosage levels

The dose of hydroxychloroquine that is prescribed will vary between patients. You must stick to the instructions given to you by your doctor or those on the dispensary label. The dosage information contained here is based on the recommended average. If your dose is at variance with this, don't alter it, unless you are told to by your GP.

In addition, the dose of hydroxychloroquine you take will be subject to the potency of the preparation you are given. The number of daily doses, the time you leave between them, and the duration of your course will be dependent on the health condition you are being treated for.

To prevent malaria:

  • Adults: Take 400 mg once daily, each 7 days.
  • Children: The dose for children is generally 6.4 mg per kg of bodyweight, once per 7 days. However, your doctor will determine the use and dose of this medication for your child.

To treat malaria:

  • Adults: Take one dose of 800 mg. This is often followed by one repeat dose of 400 mg 6 to 8 hours afterwards, and then 400 mg each day on the 2nd and 3rd days.
  • Children: The dose for children is usually 32 mg per kg of bodyweight, taken over three days. However, your doctor will determine the use and dose of this medication for your child.

For the treatment of rheumatoid arthritis:

  • Adults: The dose is generally 6.5 mg per kg of bodyweight, once daily. However, your doctor will determine the use and dose of this medication.

If you forget to take one of your hydroxychloroquine tablets, you must take it immediately. However, if your next dose is almost due, leave out the dose you forgot and revert to your usual dosage regimen. Do not take a double dose.

If you do not think that you condition has become any better, or if you think you are feeling worse, you should check with your GP right away. However, do not stop taking hydroxychloroquine unless you are told to do so by your doctor.


Drug interactions

There are some medications that should never be used together. However, sometimes it may be applicable to use two drugs at the same time, even though doing so could cause an interaction between them. If this applies in your case, your GP may alter the dose of one of your drugs or advise precautions that you can take to mitigate any potential interactions. You must tell your GP if you are already using any prescription or over the counter drugs, especially if they are included in the list that follows.

It is not recommended that hydroxychloroquine is used with any of the following medications. Your GP may decide to use an alternative to this drug or perhaps change some of the other medications that you use:

  • Ziprasidone
  • Thioridazine
  • Terfenadine
  • Sparfloxacin
  • Saquinavir
  • Piperaquine
  • Pimozide
  • Mesoridazine
  • Dronedarone
  • Cisapride
  • Bepridil
  • Aurothioglucose
  • Amisulpride
  • Amifampridine
  • Zuclopenthixol
  • Vorinostat
  • Voriconazole
  • Vinflunine
  • Vilanterol
  • Venlafaxine
  • Vemurafenib
  • Vardenafil
  • Vandetanib
  • Triptorelin
  • Trimipramine
  • Trazodone
  • Toremifene
  • Tolterodine
  • Tizanidine
  • Tetrabenazine
  • Telithromycin
  • Telavancin
  • Telaprevir
  • Tamoxifen
  • Tacrolimus
  • Sunitinib
  • Sulpiride
  • Sotalol
  • Sorafenib
  • Solifenacin
  • Sodium Phosphate, Monobasic
  • Sodium Phosphate, Dibasic
  • Sodium Phosphate
  • Sevoflurane
  • Sertindole
  • Ritonavir
  • Risperidone
  • Rilpivirine
  • Ranolazine
  • Quinine
  • Quinidine
  • Quetiapine
  • Protriptyline
  • Propafenone
  • Promethazine
  • Prochlorperazine
  • Procainamide
  • Probucol
  • Posaconazole
  • Pitolisant
  • Pipamperone
  • Pimavanserin
  • Perphenazine
  • Perflutren Lipid Microsphere
  • Pentamidine
  • Pazopanib
  • Pasireotide
  • Paroxetine
  • Panobinostat
  • Paliperidone
  • Ondansetron
  • Olanzapine
  • Ofloxacin
  • Octreotide
  • Norfloxacin
  • Nilotinib
  • Nelfinavir
  • Nafarelin
  • Moxifloxacin
  • Mizolastine
  • Mifepristone
  • Metronidazole
  • Methadone
  • Mefloquine
  • Lumefantrine
  • Levofloxacin
  • Leuprolide
  • Lapatinib
  • Ketoconazole
  • Ivabradine
  • Itraconazole
  • Imipramine
  • Iloperidone
  • Ibutilide
  • Hydroxyzine
  • Hydroquinidine
  • Histrelin
  • Haloperidol
  • Halofantrine
  • Granisetron
  • Goserelin
  • Gonadorelin
  • Gemifloxacin
  • Gatifloxacin
  • Galantamine
  • Fosphenytoin
  • Foscarnet
  • Formoterol
  • Fluoxetine
  • Fluconazole
  • Flecainide
  • Fingolimod
  • Felbamate
  • Famotidine
  • Escitalopram
  • Erythromycin
  • Eribulin
  • Efavirenz
  • Ebastine
  • Droperidol
  • Doxepin
  • Donepezil
  • Domperidone
  • Dolasetron
  • Dofetilide
  • Disopyramide
  • Deslorelin
  • Desipramine
  • Delamanid
  • Degarelix
  • Dasatinib
  • Dabrafenib
  • Cyclobenzaprine
  • Crizotinib
  • Clozapine
  • Clomipramine
  • Clarithromycin
  • Citalopram
  • Ciprofloxacin
  • Chlorpromazine
  • Chloroquine
  • Buserelin
  • Bedaquiline
  • Azithromycin
  • Atazanavir
  • Astemizole
  • Asenapine
  • Arsenic Trioxide
  • Aripiprazole
  • Apomorphine
  • Anagrelide
  • Amitriptyline
  • Amiodarone
  • Alfuzosion

Using hydroxychloroquine with Digoxin can present an increased risk of some side effects. However, using both medicines at the same time may be the best treatment in your case. Your doctor may change the dose of one or both of the drugs or the frequency with which you use them.

Other interactions

Some drugs must not be used when you are eating or with certain food groups. In addition, using alcohol or tobacco should be avoided while using some drugs. You should discuss this aspect of your treatment with your GP.

Medical interactions

Some existing or historical health conditions can influence how hydroxychloroquine works. Be sure to discuss your medical history fully, before you start using this medication.

If you have ever suffered from any severe blood diseases, do not use hydroxychloroquine as this could cause blood disorders.

If you have any problems with your vision, note that hydroxychloroquine can cause serious visual side effects, especially if taken in high doses.

Hydroxychloroquine should not be used in patients who have glucose-6-phosphate dehydrogenase (G6PD) deficiency, as doing so could cause serious side effects.

Patients with kidney or liver diseases should not be treated with hydroxychloroquine as this drug can cause increased side effects or affect dosage levels due to the slower removal of the drug from the body.

Hydroxychloroquine can cause seizures and muscle weakness when taken in high doses. Patients with a history of brain or severe nervous disease should not take this medicine.

Hydroxychloroquine can make porphyria worse and must be used with caution in patients with this condition.

Hydroxychloroquine can cause severe psoriasis outbreaks and caution should be exercised when taking this drug.

Hydroxychloroquine can sometimes cause irritation to the stomach lining. Patients with severe intestinal or stomach problems should exercise caution when using this drug.


Before you decide to use hydroxychloroquine, you must consider the risks of doing so as well as the benefits. This decision is best made following discussions with your GP. In addition, you should consider the following factors:


You must let your GP know if you have a history of allergic reactions to hydroxychloroquine or to any other drugs, including over the counter products. Tell your GP if you know that you are allergic to any food preservatives, additives, colors, animal derivatives, or particular food groups.


It must be noted by parents that young children are more susceptible to the effects of hydroxychloroquine than adults. As a result, side effects may be more likely during treatment, and overdose is extremely dangerous. In fact, it has been reported that taking as few as three or four tablets of chloroquine has proven fatal in very small children.


There is no evidence to suggest that using hydroxychloroquine in elderly people presents any specific risk. If you have any concerns in this regard, you should discuss them with your GP.

Pregnancy and breastfeeding

As far as can be determined, it is not harmful to the fetus if the mother is using hydroxychloroquine while she is pregnant. It is also not considered a risk to the infant if this drug is used while a mother is breastfeeding. However, if you are worried about this aspect of your treatment, you should discuss this with your GP and midwife.

Medical complications

If you begin to experience blurred vision, problems in focusing when reading, or any other visual changes during or following long-term use of hydroxychloroquine, you must check with your GP right away. It may be recommended that you have your eyes tested by a specialist.

Hydroxychloroquine can cause visual disturbances, including blurred vision. Some people may also feel lightheaded or dizzy. Be sure that you know how you will react to this drug before driving, operating machinery, or undertaking any potentially dangerous activity that requires clear vision and clarity of mind. If these effects do not resolve within a couple of weeks, speak to your GP.

Preventative measures for malaria

Malaria is carried by mosquitoes. If you are intending to travel to an area of the world where malaria is prevalent, you should take the following preventative measures to avoid contracting the disease:

1. Whenever possible, try to sleep under mosquito netting to avoid getting bitten by mosquitoes.

2. From dusk to dawn while mosquitoes are active, you should wear clothing that covers your skin.

3. Use mosquito repellent containing DEET on all exposed areas of your skin.


Keep your hydroxychloroquine medication in a sealed container to protect the tablets from moisture. Keep the tablets away from direct sunlight and from sources of heat. Do not freeze the tablets.

Be extremely careful to place your hydroxychloroquine tablets well out of the reach of children and pets. If you suspect that a child has eaten any of your medication, seek emergency medical help immediately. If a pet has consumed any hydroxychloroquine tablets, contact your emergency vet right away.

Do not keep any hydroxychloroquine tablets that have become out of date or are no longer required. Return any unused medicines to your pharmacist or GP for safe disposal.


Hydroxychloroquine is an antiprotozoals and disease-modifying anti-rheumatic medication. This drug is used to treat certain forms of malaria, a disease that is carried in mosquito bites. Hydroxychloroquine is also used to treat protozoan conditions of the liver and for some autoimmune diseases such as rheumatoid arthritis and lupus erythematosus.

Hydroxychloroquine will not work for chloroquine-resistant strains of malaria. If you are due to travel to a country where you know that malaria is prevalent, ask your doctor for guidance on the correct anti-malarial drugs to use.

This medication can cause side effects, especially in patients who have a history of certain medical conditions. There are also a great many drugs that should not be used in conjunction with hydroxychloroquine, due to the potential interactions that doing so could cause. For these reasons, you should have a full discussion of your medical history with your GP before you begin taking this drug.

It should be noted that, although hydroxychloroquine can be used in children, it can be extremely dangerous if taken in too high a dose. For this reason, you should take care to store your hydroxychloroquine tablets well out of reach of children, and never allow your child to self-medicate with this drug unless an adult is present to supervise the dosage.