Hydroxychloroquine: Formula, Uses, Side Effects


Hydroxychloroquine is primarily an anti-malarial drug, which is used to prevent or treat malaria caused by mosquito bites. It is also used to treat certain auto-immune diseases, such as lupus and rheumatoid arthritis. This medication belongs to a class of medications known as disease-modifying antirheumatic drugs (DMARDs). It is, in fact, a more soluble and less toxic metabolite of chloroquine. Chloroquine was first used as prophylaxis and treatment for malaria. Hydroxychloroquine is mostly sold as a sulfate salt known as hydroxychloroquine sulfate with various brand names, such as Plaquenil (in the US), Hydroquin, Axemal (in India), Dolquine, Quensyl, and Quinoric.


Hydroxychloroquine made headlines amid the Corona outbreak in 2020 when the US President Donald Trump stressed over its import to help cure the Corona patients.

Hydroxychloroquine and Donald Trump

Although several in vitro (outside of a living organism) studies have reported antiviral activity of chloroquine and hydroxychloroquine against SARS-CoV-2, there is insufficient in vivo (inside of a living organism) evidence to recommend its use for COVID-19.

Hydroxychloroquine and COVID-19


The hydroxyl group (-OH) present in hydroxychloroquine makes it more soluble and less toxic than its precursor chloroquine.

Hydroxychloroquine FormulaUses

Being a disease-modifying drug, hydroxychloroquine can modify the underlying disease process, rather than simply treating the symptoms. This medication is only administered in oral-tablet form. Remember, never crush, cut, or break hydroxychloroquine tablets. It acts by regulating the activity of the immune system. However, still, there is no evidence why this medication is effective for autoimmune conditions. Over the long term, it can reduce pain, swelling, and joint stiffness. If you have lupus, it may also improve the rash. It’s important to note that this drug doesn’t show immediate effects, and it may be as long as 12 weeks before you notice the benefits. More importantly, it is often taken in combination with other drugs such as methotrexate. Amid the clamour for the drug during the Corona outbreak, let’s discuss its most authentic uses in a more scientific and logical way.

Hydroxychloroquine Uses

Hydroxychloroquine is used to treat:

  • Rheumatoid Arthritis
  • Porphyria cutanea tarda
  • Discoid and Systemic Lupus Erythematosus (SLE)
  • juvenile Idiopathic Arthritis (JIA)
  • Q Fever
  • Malaria

1. Rheumatoid Arthritis

Hydroxychloroquine and Rheumatoid Arthritis

Rheumatoid Arthritis (RA) is a long term autoimmune disorder that primarily affects joints; leading to a high degree of disability. Hydroxychloroquine is the most commonly used drug to treat Rheumatoid Arthritis; because of its lower toxicity compared to chloroquine (CQ). It’s generally given in 200 mg or 400 mg doses, once per day, and on an average, it takes at least six months to get the full benefits.

2. Porphyria cutanea tarda

Hydroxychloroquine and Porphyria cutanea tarda

Porphyria cutanea tarda (PCT) is an iron-related disorder caused by reduced activity of hepatic uroporphyrinogen decarboxylase (UROD). It can generally be treated by phlebotomy or low doses of hydroxychloroquine. In this case, patients are generally given a low dose of hydroxychloroquine (100 mg orally, twice weekly, until at least 1 month after they had normal plasma levels of porphyrin).

3. Discoid and Systemic Lupus Erythematosus (SLE)

Hydroxychloroquine and Lupus

In Lupus Erythematosus, the human immune system becomes hyperactive and attacks healthy tissues; damaging different body systems, like joints, skin, kidneys, blood cells, heart, and lung. Hydroxychloroquine and chloroquine were originally used to prevent or treat malaria. However, during World War II, it was also found that these medications were effective in treating the symptoms of lupus.

4. Juvenile Idiopathic Arthritis (JIA)

Hydroxychloroquine and Juvenile Idiopathic Arthritis

This autoimmune disorder involves joint inflammation (arthritis) that first appears before the age of 16. Although hydroxychloroquine is not prescribed frequently for the treatment of juvenile idiopathic arthritis (JIA), it may be used as part of a treatment programme alongside one or two other disease-modifying anti-rheumatic drugs (DMARDs).

5. Q Fever

Hydroxychloroquine and Q Fever

Q Fever is caused by infection with Coxiella burnetii, a bacterium that affects humans and other animals. This bacterium is mostly found in cattle, sheep, goats, and other domestic mammals, such as cats and dogs. Patients with mild Q Fever generally don’t need any medication, they recover without antibiotic treatment; however, in chronic Q Fever, treatment with a combination of antibiotics including doxycycline and hydroxychloroquine for several months plays a significant role.

6. Malaria

Hydroxychloroquine and Malaria

Malaria is a mosquito-borne infectious disease that causes symptoms, like fever, tiredness, vomiting, and headaches. Hydroxychloroquine is the most advanced synthetic form of anti-malarial drugs, and it is considered one of the most recommended drugs to cure the disease.

Side Effects

The more common side effects of hydroxychloroquine include:

  • Headache
  • Dizziness
  • Diarrhea
  • Stomach Cramps
  • Vomiting

Apart from these, there are some serious side effects of hydroxychloroquine too. Let’s discuss them in detail

1. Retinopathy (Damage of Eyes)

Hydroxychloroquine and Retinopathy

The most common and serious side effect of hydroxychloroquine is retinopathy. Although there is negligible risk of macular toxicity in people taking 400 mg of hydroxychloroquine or less per day, it has more serious side-effects with chronic use (in people who take it over five years or has a cumulative dose of more than 1000 grams). The two distinct areas of the eye affected by the toxicity of hydroxychloroquine are the macula and the cornea.

2. Interaction With Other Drugs

Hydroxychloroquine Reaction with Other Drugs

If you are taking other medications, hydroxychloroquine may interact with them and restrict their effect, which may be harmful. For example, taking digoxin (a popular heart drug) with hydroxychloroquine may increase the levels of digoxin in your body; leading to increased side effects from digoxin.

3. Allergic Reactions

In some rare cases, hydroxychloroquine triggers allergic reactions, such as hives, swelling, and trouble breathing.

4. Liver Damage

There are reports that if an alcoholic takes hydroxychloroquine, it may damage his/her liver significantly, and it would also hinder the therapeutic effects of the drug.

5. Skin-related Problems

Hydroxychloroquine and Skin Related Problems

People with skin problems are advised not to take hydroxychloroquine; as it may worsen the skin conditions and can lead to psoriasis and porphyria.

6. RBC Rupture

Hydroxychloroquine and RBC Rupture

People with certain enzyme deficiencies, such as low levels of glucose-6-phosphate dehydrogenase (G6PD), should avoid taking hydroxychloroquine; as it may cause red blood cells to rupture (break open).

7. Kidney-related Side Effects

Elderly people with reduced kidney function should also avoid taking hydroxychloroquine; as they may not be able to process this drug well, which can increase the risk of side effects, including vision damage.

8. Hair Loss

In rare cases, the loss of hair has been reported by some patients undergoing prolonged treatment.

9. Vertigo

Principal Charming Vertigo GIF

The prolonged use of hydroxychloroquine may also develop the symptom of vertigo in some patients.

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  1. Sushant Kumar

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