Hydroxychloroquine: Definition, uses and side-effects & Covid-19 treatment

What is Hydroxychloroquine ?

Hydroxychloroquine (also known as hydroxychloroquine sulfate) is used for the treatment of rheumatoid
arthritis, and discoid and systemic lupus erythematosus, in patients who have not responded satisfactorily to drugs with less potential for serious side effects. It’s brand name Plaquenil. Plaquenil may be used as part of combination therapy. That means you may need to take it with other drugs.

Is Hydroxychloroquine applicable for the treatment of COVID-19 ?

Hydroxychloroquine was approved for medical use in the United States in 1955. In 2017, it was the 128th most commonly prescribed medication in the United States, with more than five million prescriptions. In June 2020, the World Health Organization (WHO) discontinued the use of Plaquenil in the international Solidarity trial, as did the United Kingdom RECOVERY Trial, when Plaquenil was shown to provide no benefit for hospitalized people severely infected with COVID-19. Please check the research Journal.


Physical and Chemical Properties of Plaquenil:

Serial No
Chemical Name

Brand Name

Other Name
Hydroxychloroquine sulfate
Chemical Formula
Molecular Weight
335.872 g.mol1
2D Structure

Hydroxychloroquine 2D Structure

3D Structure

Hydroxychloroquine 3D Structure

Variable (74% on average); Tmax = 2–4.5 hours
Pharma – Kinetic Data
  • Protein Binding

  • Half-life

  • Excretion

  • 45%

  • 32–50 days

  • Mostly kidney (23–25% as unchanged drug), also biliary (<10%)


Limitations for taking Hydroxychloroquine sulfate tablet
Major Side-effects of Hydroxychloroquine
Hydroxychloroquine is taken in
tablet form, with or after food.
Your doctor will advise you about
the correct dose. Usually, you will
start on a full dose of 200–400 mg
daily, and later your doctor may
reduce this. When your condition
is very well controlled you may be
advised to take hydroxychloroquine
only 2–3 times per week.
Unless you have severe side-effects it’s important to keep
taking hydroxychloroquine:
• even if it doesn’t seem to
be working at first
• even when your symptoms
start to improve – to help keep
the disease under control.
some people
hydroxychloroquine can cause:
• skin rashes, especially those
made worse by sunlight
• feeling sick (nausea) or indigestion
• diarrhea
• headaches
• bleaching of the hair or mild hair loss
• ringing in the ears (tinnitus)
• blurred vision.

• There is a small risk that hydroxychloroquine may damage the retina (a part of the eyes).

• Neuropsychiatric adverse effects of hydroxychloroquine use include agitation, mania, difficulty sleeping, hallucinations, psychosis, catatonia, paranoia, depression, and suicidal thoughts.
• Serious skin reactions such as Stevens-Johnson syndrome, toxic epidermal necrolysis, and Drug reaction with eosinophilia and systemic symptoms.
• Blood abnormalities with its use include lymphopenia, eosinophilia, and atypical lymphocytosis.

• For the prolonged treatment of lupus or rheumatoid arthritis, adverse effects include:

  • plus altered eye pigmentation,
  • acne,
  • anemia,
  • bleaching of hair,
  • blisters in mouth and eyes,
  • blood disorders,
  • cardiomyopathy,
  • convulsions,
  • vision difficulties,
  • emotional changes,
  • excessive coloring of the skin,
  • hearing loss,
  • liver problems or liver failure,
  • loss of hair,
  • muscle paralysis,
  • weakness or atrophy,
  • nightmares,
  • skin inflammation and scaling, skin rash,
  • weight loss, and occasionally urinary incontinence.
  • Hydroxychloroquine can worsen existing cases of both psoriasis and porphyria.
  • Children may have vulnerable adverse effects from hydroxychloroquine.

Data Sources: Source-1, Source-2

You can see the CDC report on Plaquenil instructions Here.

Plaquenil safety precautions here

Plaquenil for the treatment of COVID-19:

Many scientists from different countries tried to invent COVID-19 drugs. They have experimented with various drugs. Among them, Plaquenil, which primarily used for malaria disease, has shown good results for some COVID-19 patients. But due to some adverse effects, it is not approved for the use of COVID-19. You may see the full documentation: Here (PDF).


Application and uses of Plaquenil :

Plaquenil is used for rheumatic disorders such as systemic lupus erythematosus, rheumatoid arthritis, and porphyria cutanea tarda, and certain infections such as Q fever and certain types of malaria.
Certain types of malaria, resistant strains, and complicated cases require different or additional medication.
Plaquenil is widely used in the treatment of post-Lyme arthritis.

How should take Plaquenil?

Taking Plaquenil exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets.

Take hydroxychloroquine with a meal or a glass of milk unless your doctor tells you otherwise.

To treat lupus or arthritis, hydroxychloroquine is usually taken daily.

To prevent malaria: Hydroxychloroquine is usually taken once per week on the same day each week. Start taking the medicine 2 weeks before entering an area where malaria is common. Keep taking the medicine during your stay and for at least 4 weeks after you leave the area.

To treat malaria: Hydroxychloroquine is usually given as one high dose followed by smaller doses during the next 2 days in a row.

Use this medicine for the full prescribed length of time, even if your symptoms quickly improve.

Call your doctor as soon as possible if you have been exposed to malaria, or if you have a fever or other symptoms of illness during or after a stay in an area where malaria is common.

Use protective clothing, insect repellents, and mosquito netting around your bed to further prevent mosquito bites that could cause malaria.

No medication is 100% effective in treating or preventing all types of malaria. Talk with your doctor if you have fever, vomiting, or diarrhea during your treatment.

While using hydroxychloroquine, you may need frequent medical tests and vision exams.

Store at room temperature away from moisture, heat, and light.

To know about dosing information please visit here: Dosing information




Wikipedia, Drugs.com, Medical News Today, CDC, Research Journal

You may have interest in: Coronavirus (COVID-19) – Stay safe

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