Hydroxychloroquine - Uses,Properties and Side Effects



How does hydroxychloroquine work?


The medication on the prescription is hydroxychloroquine. As a tablet for oral consumption. Plaquenil, a brand-name drug, is the name of the substance hydroxychloroquine. Additionally, a generic version is offered. Drugs that are generic typically cost less than those that are brand-name. They might not always be offered in every strength or form that the brand-name medication is.

As a component of a combination (Azithromycin) therapy, hydroxychloroquine may be used. Therefore, you might have to combine it with other medications.


The drug hydroxychloroquine is a member of the class of drugs known as "antimalarials" (AMS), also known as disease-modifying anti-rheumatic drugs (DMARDs). These medications were once used to treat and prevent malaria, but they are no longer used for those purposes because more potent medications have been created. The AMs of today are quinacrine, hydroxychloroquine, and chloroquine. (Quinacrine is no longer marketed in the United States; a compounding pharmacy can still dispense it, but insurance companies might not cover the cost.)

In 1834, cutaneous lupus was first managed with antimalarial quinine. The treatment of discoid and subacute cutaneous lupus with another drug that is similar to quinine produced positive results in later reports from 1928 and 1938. Atabrine, a drug created in Germany in the 1920s, was successfully used to treat discoid lupus patients in 1941. Both hydroxychloroquine (HCQ) and chloroquine (CQ) had been synthesised by the middle of the 1940s. The efficacy of HCQ for rheumatoid arthritis and systemic lupus was demonstrated in 1955. Dubois' Lupus Erythematosus, Wallace DJ, Hahn BH, eds. 1997:1117.




Medical usage


Hydroxychloroquine is used to treat certain infections like Q fever and some forms of malaria as well as rheumatic diseases like systemic lupus erythematosus, rheumatoid arthritis, and porphyria cutanea tarda.


It is regarded as the primary therapy for systemic lupus erythematosus.


Different or additional medications are needed for complicated cases, resistant strains, and specific types of malaria.

Despite being frequently used, it does not seem to be a successful treatment for primary Sjögren syndrome.

Post-Lyme arthritis is commonly treated with hydroxychloroquine. Similar to the treatment for rheumatoid arthritis, it may have both anti-spirochete and anti-inflammatory properties.


 Negative impact


There is little difference between toxic and therapeutic doses of hydroxychloroquine due to its narrow therapeutic index.


The most frequent side effects are diarrhoea, cramps in the stomach, and nausea. Itching and headache are some additional frequent negative effects. The eye is affected by the most severe side effects, with dose-related retinopathy remaining a concern even after the use of hydroxychloroquine is stopped. Agitation, mania, trouble sleeping, hallucinations, psychosis, catatonia, paranoia, depression, and suicidal thoughts are just a few of the serious neuropsychiatric side effects of hydroxychloroquine use that have been documented. 


Hydroxychloroquine has occasionally been linked to severe skin reactions like Stevens-Johnson syndrome, toxic epidermal necrolysis, and drug reactions with eosinophilia and systemic symptoms. There have been reports of lymphopenia, eosinophilia, and atypical lymphocytosis in connection with its use.


Adverse effects of the short-term treatment of acute malaria can include nausea, vomiting, headaches, diarrhoea, heart issues, reduced appetite, and abdominal cramps. Low blood sugar and a prolonged QT interval are two additional side effects associated with short-term Hydroxychloroquine use.


There have been idiosyncratic hypersensitivity reactions.


Adverse effects of long-term lupus or rheumatoid arthritis treatment include the acute symptoms as well as changes in eye pigmentation, acne, anaemia, bleaching of hair, blisters in the mouth and eyes, blood disorders, convulsions, vision problems, diminished reflexes, emotional changes, excessive skin colouring, hives, itching, liver issues or liver failure, loss of hair, muscle paralysis, weakness or atrophy, nightmares, psoriasis, Hydroxychloroquine can make existing conditions worse.


Children may be especially vulnerable to developing adverse effects from hydroxychloroquine overdose 




Hydroxychloroquine overdoses are extremely rare but extremely toxic. Since the drug's introduction in the middle of the 1950s, eight individuals have overdosed, with three of them dying as a result. In contrast to hydroxychloroquine, which is thought to be two or three times less toxic, chloroquine has an adult overdose risk of death of about 20%.


Usually, within an hour of ingestion, serious overdose signs and symptoms appear. Sleepiness, vision changes, seizures, coma, stopping of breathing, and heart issues like ventricular fibrillation and low blood pressure are a few of these that may occur. Vision loss might be irreversible. It is also possible to have low blood potassium of 1 to 2 mmol/L. There may also be cardiovascular anomalies like widening of the QRS complex and lengthening of the QT interval.



Early mechanical ventilation, heart monitoring, and activated charcoal are all suggested forms of treatment. Epinephrine is the preferred vasopressor. Supportive care may be necessary, including intravenous fluids and vasopressors. In addition, stomach pumping may be used. In cases of severe QRS complex widening, sodium bicarbonate and hypertonic saline may be used. Benzodiazepines can be used to treat seizures. It might be necessary to administer intravenous potassium chloride, but doing so could lead to high blood potassium levels later on in the course of the illness. It doesn't seem like dialysis is helpful.



Does it address CIV 19?


In order to prevent COVID-19, the World Health Organisation (WHO) does not suggest hydroxychloroquine. This recommendation is based on six tests with healthy volunteers. Experts discovered that hydroxychloroquine had little to no effect in preventing infection, hospitalisation, or death from COVID-19 in these patients.


Also not recommended by WHO as a COVID-19 treatment is a hydroxychloroquine. Researchers conducted 30 trials with more than 10,000 COVID-19 cases. The requirement for (or duration of use of) ventilators or the risk of death was not reduced by hydroxychloroquine.

For a brief period, the Food and Drug Administration (FDA) permitted the use of hydroxychloroquine in emergencies. After a sizable study revealed no proof that the medication could prevent deaths or hasten the recovery of those with COVID-19, they withdrew their approval.




Your heart may be adversely affected by hydroxychloroquine, particularly if you also take certain other medications, such as the antibiotic azithromycin (Z-Pak). If you experience sudden dizziness and a racing or pounding heartbeat, call for emergency medical help (like you might pass out).

Long-term or high-dose use of hydroxychloroquine may permanently harm the retina of your eye, leading to vision problems that cannot be reversed.

If you experience blurred vision, difficulty focusing, distorted vision, blind spots, difficulty reading, changes in your colour vision, or increased sensitivity to light, stop taking hydroxychloroquine and contact your doctor right away.


Prior to using this medication


If you are allergic to chloroquine or hydroxychloroquine, you should avoid using it.

The retina may suffer irreparable harm if you use hydroxychloroquine in high doses or for an extended period of time (the membrane layer inside your eye that helps produce vision). This could develop into long-term vision issues. People with pre-existing eye conditions, kidney disease, or those who also take tamoxifen have a higher risk of retinal damage.

If you have ever had any of the following conditions, let your doctor know so they can make sure you can safely take hydroxychloroquine: Porphyria, a genetic enzyme disorder that results in symptoms affecting the skin or nervous system, alcoholism, psoriasis, changes in vision or retinal damage brought on by anti-malaria medication, heart disease, heart rhythm disorders (like long QT syndrome), diabetes, a stomach condition, and a quinine allergy are just a few of the conditions that can affect one's ability to process quinine.

If you are pregnant or intend to become pregnant, let your doctor know. A pregnant woman is more likely to develop a serious illness from malaria or pass away from it. In addition to increasing the risk of miscarriage, stillbirth, early delivery, and low birth weight, malaria during pregnancy may also increase these risks.


A pregnancy registry may include your name if you're expecting it in order to monitor the impact of the drug on the foetus.


The safety of hydroxychloroquine during pregnancy is unknown. Consult your doctor about the dangers of travelling to areas where malaria is prevalent if you are expecting a child (such as Africa, South America, and Southern Asia).


While taking this medication, breastfeeding might not be safe. Inquire with your doctor about any risks.

Anyone under the age of 18 cannot be treated for lupus or rheumatoid arthritis with hydroxychloroquine.




It is crucial that your doctor regularly assess your progress to ensure that the medication is doing its job. Tests on the blood and urine may be required to look for side effects.


If you experience blurred vision, trouble reading, or any other change in vision during or after treatment, consult your doctor right away. Your doctor might request that an ophthalmologist examine your eyes (eye doctor).

If you notice any changes in your heart rhythm, call your doctor right away. Your heartbeat could be quick, pounding, or uneven, and you might feel lightheaded or faint. Make sure your doctor is aware of any heart rhythm issues you've had, such as QT prolongation.


This medication may result in issues with the muscles and nerves. If you experience any muscle aches, pains, or tenderness while taking this medication, speak with your doctor right away.


Some people who take hydroxychloroquine may become agitated, irritable, or exhibit other abnormal behaviours. Additionally, it might make some people more depressed or have suicidal thoughts and tendencies. Inform your doctor as soon as possible if you or your caregiver experience any of these side effects.


This drug may result in hypoglycemia (low blood sugar). When this medication is taken along with other medications, this happens more frequently. In order to avoid passing out due to low blood sugar, it must be treated (unconsciousness). Low blood sugar symptoms vary from person to person. It's critical to identify your typical symptoms so you can treat the condition quickly. Consult your doctor for advice on how to handle low blood sugar.

This medication causes your body to have fewer of some blood cell types. You might bleed or get infections more quickly as a result. Avoid being around sick or infected people to help with these issues. Regularly wash your hands. Avoid rough sports and other situations where you could get cut, bruised, or hurt. Gently floss and brush your teeth. Use caution when working with anything sharp, such as razors and nail clippers. If you suspect an infection is developing or if you experience fever, chills, cough or hoarseness, lower back or side pain, or painful or challenging urination, call your doctor right away.

During treatment with this medication, severe skin reactions like Stevens-Johnson syndrome, toxic epidermal necrolysis, drug reaction with eosinophilia and systemic symptoms (DRESS), and acute generalised exanthematous pustulosis can happen. Consult a medical professional right away if you or your child experiences any of the following symptoms: black, tarry stools; blistering, peeling, or loosening of the skin; chest pain; chills; cough; diarrhoea; itching; joint or muscle pain; painful or challenging urination; red, irritated eyes; red skin lesions, often with a purple centre; severe acne or skin rash; sore throat; sores, ulcers, or white spots in the mouth

Consult your doctor if your symptoms do not go away within a few days (or a few weeks or months for arthritis) or if they worsen.

Certain types of infected female mosquitoes bite people to transmit malaria. The following mosquito-control measures will aid in preventing infection if you reside in or will be visiting an area where there is a risk of contracting malaria:


  • If at all possible, stay inside between dusk and dawn, when mosquitoes are most active and more likely to bite.
  • Remain in well-screened or air-conditioned rooms to minimise mosquito contact.
  • To protect your arms and legs, wear long-sleeved shirts or blouses and long pants, especially from dusk until dawn when mosquitoes are active.
  • Apply insect repellent to exposed skin, preferably one with DEET, from dusk until dawn when mosquitoes are active.
  • Avoid being bitten by mosquitoes that carry malaria by sleeping in screened or air-conditioned rooms or under mosquito netting, preferably netting that has been coated or soaked in pyrethrum.
  • During the evening and night, use mosquito coils or sprays to eliminate mosquitoes from living and sleeping areas.
  • Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines) and herbal or vitamin supplements.




The German government looked for alternatives to quinine as a malaria preventative after World War I. In 1934, Hans Anderson and colleagues at the Bayer laboratories discovered chloroquine, a synthetic analogue with the same mode of action. This was first used in clinical settings to treat malaria as a preventative measure in 1947. Hydroxychloroquine was one of the structural analogues with superior properties that researchers later tried to find.


Synthesis of chemicals

In a 1949 patent application, Sterling Drug disclosed the first method of synthesising hydroxychloroquine.

In the final step, a primary amine that had been created from the chloro-ketone shown was reacted with 4,7-dichloroquinoline.




Side effects of hydroxychloroquine

If you experience symptoms of an allergic reaction to hydroxychloroquine, such as hives, difficulty breathing, swelling in your face or throat, or a severe skin reaction, seek emergency medical attention (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

Additionally, if you experience any of the following signs of a serious heart condition: rapid or pounding heartbeats, fluttering in the chest, shortness of breath, or sudden dizziness (like you might pass out).

The drug hydroxychloroquine could have negative side effects. If you experience any of the following:


  • seizures, eye yellowing, ringing in the ears, hearing difficulties, strange mood swings, extreme muscle weakness, loss of coordination, and slow reflexes;
  • any abrupt changes in behaviour or mood, or suicidal thoughts;
  • Low blood cell counts can cause flu-like symptoms, chills, fatigue, mouth sores, easy bruising, unusual bleeding, pale skin, cold hands and feet, and dizziness or shortness of breath;
  • Low blood sugar symptoms include headache, hunger, sweating, irritability, dizziness, a fast heartbeat, and feelings of anxiety or trembling. Serious drug reactions can cause skin rash, fever, swollen glands, muscle aches, extreme weakness, unusual bruising, or yellowing of the skin or eyes.
  • Taking hydroxychloroquine long-term or at high doses may cause irreversible damage to the retina of your eye. Stop taking hydroxychloroquine and tell your doctor if you have:
  • blurred vision, trouble focusing, trouble reading;
  • distorted vision, blind spots;
  • changes in your colour vision;
  • hazy or cloudy vision;
  • seeing light flashes or streaks, seeing halos around lights; or
  • increased sensitivity to light.
  • Headache, dizziness, nausea, vomiting, stomach pain, loss of appetite, weight loss, feeling anxious or irritable, skin rash or itching, or hair loss are some of the more typical side effects of hydroxychloroquine.