Hydroxychloroquine and Antimalarial Drugs (united healthcare)

Hydroxychloroquine and Antimalarial Drugs (united healthcare)

These are antimalarial drugs found to induce remission in upto 50% patients of Rheumatoid Arthritis (RA), but take 3–6 months. Their advantage is relatively low toxicity, but efficacy is also low; bony erosions are not prevented. Their mechanism of action is not known, however, they have been found to reduce monocyte IL–I, consequently inhibiting B lymphocytes. Antigen processing may be interfered with. Lysosomal stabilization and free radical scavenging are the other proposed mechanisms.
For RA, these drugs have to be given for long periods: accumulate in tissues (especially melanin containing tissue) and produce toxicity, most disturbing of which is retinal damage and corneal opacity. This is less common and
reversible in case of hydroxychloroquine, which is preferred over chloroquine. Other adverse effects are rashes, graying of hair, irritable bowel syndrome, myopathy and neuropathy.

Chloroquine/hydroxychloroquine are employed in milder nonerosive disease, especially when only one or a few joints are involved, or they are combined with Mtx/sulfasalazine.

Hydroxychloroquine 400 mg/day for 4–6 weeks, followed by 200 mg/day for maintenance.

These are drugs used for prophylaxis, treatment and prevention of relapses of malaria.
Malaria, caused by 4 species of the protozoal parasite Plasmodium, is endemic in most parts of India and other tropical countries.

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It is one of the major health problems. As per latest WHO estimates (2011)* between 149–274 (median 216) million clinical cases and ~ 0.655 million deaths occur globally due to malaria each year,90% of which are in Africa. This amounts to one malaria death every minute.

The WHO estimates that actual number of malaria cases in India is much higher, and an expert committee has estimated that about 40,000 malaria deaths occur annually.

The bark of Cinchona tree, growing in Peru, was introduced in Europe in the early 17th century as a cure for fevers. Later it was realized to be a specific remedy for malaria. Quinine, isolated from Cinchona bark in 1820, replaced the crude preparation and continued to be the major antimalarial drug till 1942.


Hydroxychloroquine is used to prevent or treat malaria caused by mosquito bites. The United States Center for Disease Control provides updated guidelines and travel recommendations for the prevention and treatment of malaria in different parts of the world. Discuss the most recent information with your doctor before traveling to areas where malaria occurs.

This medication is also used to treat certain auto-immune diseases (lupus, rheumatoid arthritis). It belongs to a class of medications known as disease-modifying antirheumatic drugs (DMARDs). It can reduce skin problems in lupus and prevent swelling/pain in arthritis.

Hydroxychloroquine is not recommended for coronavirus infection, also known as COVID-19, unless you are enrolled in a study. Talk to your doctor about the risks and benefits.

Side Effects

Nausea, vomiting, loss of appetite, diarrhea, dizziness, or headache may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including: slow heartbeat, symptoms of heart failure (such as shortness of breath, swelling ankles/feet, unusual tiredness, unusual/sudden weight gain), mental/mood changes (such as anxiety, depression, rare thoughts of suicide, hallucinations), hearing changes (such as ringing in the ears, hearing loss), easy bruising/bleeding, signs of infection (such as sore throat that doesn’t go away, fever), signs of liver disease (such as severe stomach/abdominal pain, yellowing eyes/skin, dark urine), muscle weakness, unwanted/uncontrolled movements (including tongue/face twitching), hair loss, hair/skin color changes.

This medication may cause low blood sugar (hypoglycemia). Tell your doctor right away if you develop symptoms of low blood sugar, such as sudden sweating, shaking, hunger, blurred vision, dizziness, or tingling hands/feet. If you have diabetes, be sure to check your blood sugars regularly. Your doctor may need to adjust your diabetes medication.

Get medical help right away if you have any very serious side effects, including: severe dizziness, fainting, fast/irregular heartbeat, seizures.

This medication may cause serious eye/vision problems. The risk for these side effects is increased with long-term use of this medication and with taking this medication in high doses. Get medical help right away if you have any symptoms of serious eye problems, including: sensitivity to light, vision changes (such as light flashes/streaks, blurred vision, difficulty reading, missing areas of vision).

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US –

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada – Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.


Before taking hydroxychloroquine, tell your doctor or pharmacist if you are allergic to it; or to chloroquine; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: a certain enzyme problem (glucose-6-phosphate dehydrogenase deficiency-G6PD), vision/eye problems, hearing problems, kidney disease, liver disease, regular alcohol use/abuse, skin problems (such as psoriasis), a certain blood disorder (porphyria), seizures.

If you have diabetes, this product may affect your blood sugar. Check your blood sugar regularly as directed and share the results with your doctor. Tell your doctor right away if you have symptoms of low blood sugar (see Side Effects section). Your doctor may need to adjust your diabetes medication, exercise program, or diet.

This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Avoid alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis). Alcohol can also increase your risk of liver problems while you are taking this drug.

This medication may make you more sensitive to the sun. Limit your time in the sun. Avoid tanning booths and sunlamps. Use sunscreen and wear protective clothing when outdoors. Tell your doctor right away if you get sunburned or have skin blisters/redness.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Hydroxychloroquine may cause a condition that affects the heart rhythm (QT prolongation). QT prolongation can rarely cause serious (rarely fatal) fast/irregular heartbeat and other symptoms (such as severe dizziness, fainting) that need medical attention right away.

The risk of QT prolongation may be increased if you have certain medical conditions or are taking other drugs that may cause QT prolongation. Before using hydroxychloroquine, tell your doctor or pharmacist of all the drugs you take and if you have any of the following conditions: certain heart problems (heart failure, slow heartbeat, QT prolongation in the EKG), family history of certain heart problems (QT prolongation in the EKG, sudden cardiac death).

Low levels of potassium or magnesium in the blood may also increase your risk of QT prolongation. This risk may increase if you use certain drugs (such as diuretics/”water pills”) or if you have conditions such as severe sweating, diarrhea, or vomiting. Talk to your doctor about using hydroxychloroquine safely.

Older adults may be more sensitive to the side effects of this drug, especially QT prolongation (see above).

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

This medication passes into breast milk. Consult your doctor before breast-feeding.


If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: fast/irregular heartbeat, fainting, slow/shallow breathing, seizures.

1. 4-Aminoquinolines

Chloroquine (CQ)
Amodiaquine (AQ)

2. Quinoline- methanol


3. Cinchona alkaloid

Quinine, Quinidine

4. Biguanide

Proguanil (Chloroguanide)

5. Diaminopyrimidine


6. 8-Aminoquinoline


7. Sulfonamides and sulfone


8. Antibiotics


9. Sesquiterpine lactones


10. Amino alcohols


11. Naphthyridine


12. Naphthoquinone


The aims of using drugs in relation to malarial infection are:
(i) To prevent clinical attack of malaria (prophylactic).
(ii) To treat clinical attack of malaria (clinical curative).
(iii) To completely eradicate the parasite from the patient’s body (radical curative).
(iv) To cutdown human-to-mosquito transmission (gametocidal).

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