Hydroxychloroquine (C18H26ClN3O) – Benefits & Side Effects

Hydroxychloroquine(C18H26ClN3O): Benefits & Side Effects

Hydroxychloroquine is an oral medication also known as Plaquenil. It is one of the medications used to treat malaria. Apart from malaria, uses include treatment of rheumatoid arthritis, lupus, and studies under the treatment of COVID 19.

It was discovered during the  2nd world war from quinacrine. It has been used as an antibiotic. Moreover, it is used in the treatment of intestinal disease and lupus.

It has minimal side effects. It is generally used in biological cell experiments as an inhibitor.

This medication is being widely used to treat the novel coronavirus. It is not yet confirmed about the safety and effectiveness of COVID 19.

But it is strongly suggested that please do not purchase medicine without the consultation of a doctor. It is being used only for clinical trials.

The FDA has approved the emergency use of HCQ only in people suffering from COVID 19 pandemic and admitted to the hospital.

HCQ can cause negative effects on the heart and long term uses of this medication can harm the retina of eyes.

In the US, HCQ was approved for prescription in  1955. As per the statement of the World Health Organisation, it is the essential medication that needed in the health system.

What is Hydroxychloroquine?

What is Hydroxychloroquine?

Hydroxychloroquine is derived from chloroquine has immunosuppressive and antimalarial activities. Moreover, it is a 4-aminoquinoline with anti-inflammatory and antiautophagy. It acts against the material parasites.

HCQ is indicated for prophylaxis of malaria treatment caused by P. malariae, P.ovale, or P.falciparum. In some cases, it has been recommended to take every week due to its long duration of action.

As it is an anti-inflammatory drug, it is prescribed for the joint stiffness, reduce pain in arthritis, and reduces the swelling. However, it is prescribed along with methotrexate, especially for joint problems.

HCQ is a Disease-modifying anti-rheumatic drug. This should be taken under the observation of a medical expert.

It is used as the first-line treatment in Lupus and Porphyria Cutanea trade. Common side effects with the medication are headache, vomiting tendency, nausea, and loss of appetite.

One more fact about this drug is not effective in all the strains of malaria. Ask for medical help if you have a fast heartbeat after using this medication and a sudden feeling of dizziness.

HCQ in Treatment of MalariaHydroxychloroquine in treatment of malaria

Malaria is a life-threatening disease caused by the bite of infected female Anopheles mosquitoes. Female Anopheles mosquitoes carry the Plasmodium parasite that is released in the human bloodstream through the bite.

About 228 million cases of malaria diagnosed in 2018 worldwide. It is a serious disease and can be a reason for death if not treated carefully.

Children under the age of 6 are more prone to this infection. It is more common in tropical areas.

A patient with malaria experience symptoms such as fever, chills, muscle pain, nausea, and vomiting. Moreover, in severe cases chest pain, abdominal pain, sweating, and cough may occur.

Once the parasite reaches in the bloodstream, they start targeting the red blood cell that is important for the transmission of oxygen throughout the body.

They start killing the healthy RBCs that fall you sick.HCQ is the antimalarial drug that is used in the treatment of acute malaria.

HCQ stops the production of toxic substances by binding itself with the toxic product to disrupt and break up the malaria parasite egg.

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HCQ in the Treatment of Rheumatoid Arthritis

HCQ in Rheumatoid Arthritis

Rheumatoid Arthritis is an autoimmune disease that affects joints. It is the condition, in which the immune system responds against the linings of your joints as “foreign” and attacks to damages them, resulting in inflammation and pain in joints.

It is a progressive disease that can damage other parts of the body such as the lungs, skin, eyes, and heart.

HCQ is anti-rheumatic medicine, which is classified under the disease-modifying anti-rheumatic drug (DMARD).

HCQ helps in the reduction of inflammation and prevent the joints from long term disability. It is used to slow or stop the RA by suppressing the immune system. For better results, it prescribed with the methotrexate.

HCQ in the Treatment of Lupus

Lupus is an autoimmune disease that affects the supportive tissues and organs. It mostly affects the different body systems including lungs, skin, joints, kidneys, blood cells, and brains.

Sign and symptoms may develop suddenly that may be mild to severe. The most common sign and symptoms include- Fatigue, Fever, Pain in joint, Skin lesions, Shortness of breath, dry eyes, Confusion, and memory loss.

A woman with lupus may increase the risk of miscarriage. The immune system starts killing the healthy tissue of your body.

It may increase the risk of cancer, frequent infection, bone tissue death, etc.

HCQ helps to treat the disease by suppressing the immune system. It treats the mild to moderate lupus, it increases the pH of lysosomes and stops their function. Lysosomes do autolysis in the cell membranes.

In autoimmune diseases, lysosomes start killing healthy tissues. It is important to stop the function of autolysis.  HCQ has proven for its good effect in suppressing immune cells to treat the auto-immune-diseases.

HCQ in the Treatment of COVID-19

HCQ in the Treatment of COVID-19

Coronavirus is the group of RNA virus that causes respiratory tract infection. It affects the lungs, throat, nose, and lower respiratory tract.

It is a contaminated disease, which transfers through the person to person contact. It can mild to severe. Severe COVID 19 may further lead to death.

The common signs and symptoms of COVID 19 include shortness of breath, fatigue, fever, headache, body ache, and loss of smell and taste.

Elevation in cytokine release may one of the causes of corona infection. It acts as a carrier in the transportation of the infection in the bloodstream and kills the healthy tissues.

The most common reason for death due to coronavirus, it develops pneumonia and septic shock.

The FDA has approved the emergency use of HCQ only in people suffering from COVID 19 pandemic and admitted to the hospital. It has approved only for the clinical trial. The exact mechanism of hydroxychloroquine is not confirmed yet.

If you are suffering from any symptoms of coronavirus, it has been suggested do not take HCQ without consulting with a doctor.

Pharmacodynamics of Plaquenil/ Hydroxychloroquine?

Hydrooxycholoquine is the derivative of acridine, which is used for the treatment of various diseases and disorders. Hydroxychloroquine disturbs the role of lysosomes both in humans and plasmodia.

Plaquenil is lipophilic weak bases and easily passes blood plasma membranes. The free base form accumulates in lysosomes, which has an acidic medium.

Plaquenil elevates the pH of the lysosomes from 4 to 6 and affects its function.

It decreases low-affinity self-antigen existence in autoimmune diseases and obstructs the lysosomal acidic protease causing reduction in proteolysis effects.

Elevation in the pH of lysosomes decreases the cell function, glycolysis secretion of proteins with many immunologic and nonimmunologic outcome.

These effects involve being the cause of a decreased immune cell functioning such as chemotaxis, phagocytosis, and few more.

Hydroxychloroquine has an action for a long period.  HCQ may be taken once in a week because some indications of hydroxychloroquine may lead to severe hypoglycemia and so diabetic patients need to check their blood sugar levels.

The exact mechanism of Plaquenil is not reported well.

Half-Life of Plaquenil

Oral Plaquenil has reported that an absorption half-life of 3-4 hours. A 200mg oral dose of Plaquenil has a half-life of 22 days in blood and about 124 days in plasma.

A 155mg intravenous dose has a half-life of near about 39.5 days.

Clearance of Plaquenil

The clearance of Plaquenil has reported 96ml/minute.

Elimination of Plaquenil

  • 45-50 % of the drug is excreted renally.
  • 5-21% of a dose is excreted through the urine as unchanged drug.
  • 5% of a drug is discarded by skin
  • 25% of the drug is eliminated through the stool.

Mechanism of Action of Hydroxychloroquine

Mechanism of Action of Hydroxychloroquine 
  • Hydroxychloroquine is developed as an antimalarial drug, but due to its activity, it considered as DMARDs. It has basic characteristics, which accumulates in the acidic medium such as lysosomes and raise their pH.
  • HCQ has a slow onset action for a prolonged period after the administration of drugs.
  • It accumulates in the lysosomes of parasites and raises the pH. The parasite needs the acidic medium to grow. HCQ prevents the growth and replication of malarial parasites.
  • Plaquenil can also hamper with the action of parasitic heme polymerase, allowing for the gathering of the virulent beta-hematin.
  • Hydroxychloroquine gathering in human tissues also elevates their pH, which obstructs antigen processing.
  • Plaquenil also reduces the release of cytokines proteins, which is responsible for the spreading the infection.
  • In the cells, it inhibits the immune activation through the reduction of proteins level in T-cells.
  • Elevated pH in endosomes, reduce the risk of viral infection in the body.
  • It stops the terminal glycosylation, which is the target receptor of entering the SARS-COV.
  • This is the way through which hydroxychloroquine interfere with the autoimmune disease and viral infection.

Plaquenil/ Hydroxychloroquine Dosage Guide

Take this medicine only as instructed by your healthcare experts. Do not take it more than the recommended dose, and do not take it for a prolonged period.

Swallow the complete dose of the tablet without broken and crushed. Take this medicine with food and milk or, as recommended by your physician.

Complete the course of treatment hydroxychloroquine, even if you feel fine after taking a few doses. Your disease may not cure if you stop using the medicine before completion of the dose.

Malaria Prophylaxis Dosing of Plaquenil/ HCQ in Adult


It is recommended by 400mg of HCQ once a week. Plaquenil should be taken on the same day and at the same time on a weekly basis.

The therapy would start before two weeks of exposure only for those areas, where chloroquine resistance has not reveled.

As per the US CDC, 310mg dose is recommended/week.

Plaquenil 400mg dose should start before two weeks of traveling and continue for 4 weeks after coming back.

If malaria develops while using the medication, it should remove from the list of treatments regimen.

Malaria Dosing of Plaquenil/ HCQ in Adult

This is indicated in the treatment of malaria only where Chloroquenil resistance is not reported. Moreover, it is recommended for infection caused by P falciparum, P malariae, P ovale, and P vivax.

800 mg salt (620 mg base) of Plaquenil orally should start as an initial dose, and it is continued by 400 mg salt (310 mg base) at 6, 24, and 48 hours after the first dose.

Maximum Dose 

800mg initial dose and followed by not to exceed 400mg dose.

Rheumatoid Arthritis Dosing of Plaquenil/ HCQ in Adult

This is recommended for the treatment of acute and chronic rheumatoid arthritis

  • 400-600 mg/day in the BID or as OID
  • When a good response is obtained, reduce dosage by 50% and continue a recommended dose of 200-400 mg/day BID;

It should not exceed 600 mg or 6.5 mg/kg per day, whichever is sustainable. As the doses increased, the chances of retinopathy would increases.

Systemic Lupus ErythematosusDosing of Plaquenil/ HCQ in Adult

This is recommended for the treatment of systemic lupus erythematosus

  • 200-400 mg/day OID as a single daily dose or in the BID
  • Doses more than 400 mg/day are not recommended to exceed

Side Effects of Hydroxychloroquine

Along with its beneficial effects, a medicine may cause some side effects. although not all the side effects may not appear after using the medication. But using for a prolonged may cause severe damage.

Check with your medical expert immediately if any of the following side effects occur:

Common Side effects are what happened after taking the medication, but if you won’t feel good call the ambulance.

  • Nausea, vomiting, weight loss, dizziness, diarrhea, headache, mood changes, irritability, nervousness, spinning sensation, skin rash, and itching may occur. If any of these causes the worst situation, immediately call the doctor.
  • If you experience severe side effects such as muscle weakness, unbalance movement, pale skin, bleeding, blurred vision, pale skin, confusion, seizures, unusual though, and dementia. You should consult your doctor immediately.
  • HCQ may reduce the blood sugar level. Consult your doctor right away if you feel symptoms of low heartbeat, shortness of breath, and sudden sweating.
  • You may experience an allergic reaction with using Hydroxychloroquine, which including skin rash, pale skin, and itching.
  • Hydroxychloroquine may cause difficulty with eye vision, blurred vision.

Symptoms of overdosing of Hydroxychloroquine

Drowsiness, dry mouth, increased thirst, mood changes, no pulse, and loss of consciousness.

A few side effects may occur that usually do not need to check with the medical expert. These side effects may cure during treatment as your body takes to get used to the medicine.

Also, your health care expert would be able to inform you about to prevent or reduce some of these side effects.

Check with your health care expert if you experience any of the following side effects are going on.

Precaution with Hydroxychloroquine

Precaution with hydoxychloroquine

Explain to your doctor and pharmacist if you are allergic to hydroxychloroquine, chloroquine, primaquine, quinine, or any other drugs.

Explain to your doctor and pharmacist about prescription and nonprescription drugs, vitamins, nutritional supplements, and herbal products you are taking or plan to take.

If you are taking these mention medication acetaminophen, azithromycin, cimetidine, cyclosporine, digoxin, insulin, and other medication for diabetes, medications for seizures such as carbamazepine,  phenytoin,  amiodarone,  methotrexate, moxifloxacin,  praziquantel, and tamoxifen.

A medical practitioner would need to change the doses of your medications or guide you for the side effects.

Several medications may also interact with hydroxychloroquine, so make sure to tell your doctor about all the medications you are taking.

In terms of antacids, you should take this medication 4 hours before or 4 hours after hydroxychloroquine.

In terms of taking ampicillin, you should take it at least 2 hours before or 2 hours after hydroxychloroquine.

Explain to your medical practitioner if you have or have ever suffered liver disease, heart disease, a prolonged QT interval, an irregular heartbeat, a low level of electrolytes in your blood.

If you are suffering from psoriasis, porphyria or other blood disorders, anemia, cancer, dermatitis (skin inflammations), seizures, vision problems, diabetes, kidney problems, and if you have any kind of addiction.

If you ever had tuberculosis, or you are suffering from this. Explain to your doctor about it and the list of medications that you are taking.

General FAQs

What does Plaquenil do to your body?

Plaquenil is also known as HCQ. It suppresses the immune system by elevating the pH of lysosomes. It reduces the production of cytokinin protein levels, which is the carrier of infection transmission throughout the body.

Is hydroxychloroquine bad for your heart?

It is reported in rare patients who had a risk of a heart attack. It can cause cardiomyopathy in patients. Moreover, hydroxychloroquine should not use for a long time, if you taking it to treat autoimmune disease, this is recommended for 6 months. For further use, you should consult with the medical practitioner.

Is Plaquenil same as hydroxychloquine?

Yes, Plaquenil is the brand name of hydroxychloroquine. it is the derivative of acridine that was discovered in 1955 as an antimalarial drug. It is used to treat the material in those areas where the resistance of chloroquine is not reported.

What does the Plaquenil do to eyes?

Prolonged uses of hydroxychloroquine/Plaquenil may damage the retina of the eye. It can be a reason of blurred vision. If you experience any symptoms related to vision, immediately call your doctor and stop taking this medication.

Is hydroxychloroquine a steroid?

It is used in the treatment of systematic lupus and it is recommended as steroids.

Can I buy hydroxychloroquine over the counter?

Hydroxychloroquine is an arthritis medicine and used in the treatment of malaria. Moreover, it is used as a preventive medicine of malaria. Now a clinical trial is going on for the patient of COVID 19. It is not allowed to buy it without a prescription. It should be taken under the observation of the doctor.

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