Plaquenil 200mg (Hydroxychloroquine)

Plaquenil general information

What is Plaquenil used for?

Plaquenil tablets 200mg are used to suppress and treat malaria, an infection caused by the protozoan (single cell) parasitic organism Plasmodium that is carried by mosquitoes.  Plasmodium is transmitted by a mosquito bite into the blood, where it migrates to the liver, grows and multiplies then released into the blood, where it and causes destruction of red blood cells.  Malaria is a life-threatening disease with symptoms including, fever, shivering, headache, vomiting, muscle pain and joint pain.  First symptoms usually appear 10 to 15 days after the mosquito bite; however, if left untreated, malaria can quickly become life-threatening, causing anaemia and brain damage and disrupting the blood supply to vital organs.  The plasmodium parasite passes through several different stages in its life cycle and Plaquenil tablets 200mg kill the infective stage of the parasite in the blood (erythrocytic forms), which breaks the life cycle of the plasmodium as well as preventing further destruction of red blood cells.  Plaquenil 200 is effective against most common forms of plasmodium, including P. vivax, P. malariae and most strains of P. falciparum, however, it not effective against chloroquine-resistant strains of P. falciparum.  Plaquenil tablets 200mg are also used to slow down the progression of chronic rheumatic diseases, such as acute and chronic rheumatoid arthritis, mild systemic lupus erythematosus (SLE) and discoid lupus erythematosus (DLE). 

How does Plaquenil work?

Plaquenil tablets 200mg contain hydroxychloroquine, the antimalarial and disease-modifying antirheumatic drug (DMARD) used to treat malaria and chronic rheumatic diseases.  Acting as an antimalarial, hydroxychloroquine in Plaquenil tablets 200mg is active against the trophozoite stage of the plasmodium parasitic life cycle that infects red blood cells and causes their destruction.  Haemoglobin, the oxygen carrying protein of blood, is released when the red blood cells are destroyed.  The plasmodium parasite digests haemoglobin forming the compound haem which is the non-protein component of haemoglobin and is toxic to cells.  Haem is converted by a parasitic polymerase enzyme to the insoluble crystalline form haemozoin that is not toxic to plasmodium.  Hydroxychloroquine in Plaquenil tablets 200mg is thought to act by inhibiting the formation of haemozoin which prevents the detoxification of haem inside the parasitic digestive system and thereby kills the parasite.  However, hydroxychloroquine is not effective against chloroquine-resistant strains of P.falciparum.  Antimalarials like hydroxychloroquine in Plaquenil tablets 200mg have also been found to have various immunomodulatory effects (ability to influence and modify the immune system) as well as antiinflamatory effects, and are classified as disease-modifying antirheumatic drug (DMARD).  There are several mechanisms by which hydroxychloroquine is thought to exert its beneficial effects as an antirheumatic drug. These include inhibition of inflammatory mediators such as interleukins and prostaglandins; also dampening down the immune response by interacting with immune cells that influence the immune response to autoantigens (directed against self) and by interfering with antigen-processing in antigen presenting cells like macrophages.  These combined actions of hydroxychloroquine in Plaquenil tablets 200mg help slow down the progression of chronic rheumatic diseases, such as acute and chronic arthritis and mild systemic lupus erythematosus (SLE) and discoid lupus erythematosus (DLE), which are thought to be autoimmune diseases (when the immune system is directed against self), but it does not act as a cure.

What does Plaquenil contain?

Plaquenil contains the active ingredient hydroxychloroquine sulfate 200 mg, the antimalarial and disease-modifying antirheumatic drug (DMARD) used to treat malaria, rheumatoid arthritis, systemic lupus erythematosus and discoid lupus erythematosus.  They also contain: calcium hydrogen phosphate, maize starch, purified water, and magnesium stearate. The film coating contains small amounts of hypromellose, macrogol 400, titanium dioxide, polysorbate 80, carnauba wax, black ink (Tekprint SB-9014SD), and purified water.

Treating malaria with Plaquenil

Plaquenil tablets 200mg are used to treat malaria, an infection caused by the protozoan (single cell) parasitic organism Plasmodium.  The most common forms of plasmodium are P. falciparum, P vivax and P.malariae.  The parasite is carried by mosquitoes and is transmitted by a bite from an infected female mosquito when the first stage of the life cycle called the sporozoite is injected into the blood while the mosquito is feeding.  It then migrates to the liver, where it matures into schizonts and multiplies.  P.vivax also has a dormant stage in the liver called the hypnozoite.  The next stage of the plasmodium life cycle called merozoite is released into the blood, infects red blood cells and transforms into the trophozoite that causes destruction of red blood cells.  Some merozoites transform into gametocytes and are taken up by a mosquito when feeding on blood to begin a new cycle.  Symptoms of malaria, including fever, shivering, headache, vomiting, muscle pain, and joint pain, usually appear 10 to 15 days after the mosquito bite.  However, if left untreated, malaria can quickly become life-threatening, causing anaemia and brain damage and disrupting the blood supply to vital organs.  Plaquenil tablets 200mg contain the antimalarial hydroxychloroquine, which is active against the trophozoite stage of the plasmodium parasitic life cycle that infects red blood cells and causes their destruction.  Haemoglobin, the oxygen carrying protein in blood, is released when the red blood cells are destroyed. The plasmodium parasite digests haemoglobin forming the compound haem which is toxic to cells.  Haem is converted by a parasitic enzyme to the insoluble crystalline form haemozoin that is not toxic to plasmodium.  Hydroxychloroquine in Plaquenil tablets 200mg is thought to act by inhibiting the formation of haemozoin which prevents the detoxification of haem inside the parasitic digestive system and thereby kills the parasite.  If the parasite survives in the blood due to inadequate anti-malarial treatment or lies dormant in the liver this can lead to recurrent malaria. Hydroxychloroquine in Plaquenil tablets 200mg are highly active against the erythrocytic forms of P.vivax and are effective in preventing acute attacks of malaria and significantly lengthening the interval between treatment and relapse.  However, they are not effective against the gametocytes of P.falciparum or chloroquine-resistant strains of P.falciparum.

Plaquenil for rheumatic diseases

Plaquenil tablets 200mg contain hydroxychloroquine, the antimalarial and disease-modifying antirheumatic drug (DMARD) used to treat chronic rheumatic diseases that have an autoimmune basis (when the immune system is directed against self), such as acute and chronic arthritis and mild systemic lupus erythematosus (SLE) and discoid lupus erythematosus (DLE).  These conditions are characterised by inflammation and destruction of tissues.  Rheumatoid arthritis is a chronic inflammation of the joints causing swelling, stiffness and pain and is due to inflammation of the synovial membrane, which forms a protective capsule around the joint.  Systemic lupus erythematosus is characterised by the formation of autoantibodies that become deposited in various parts of the body and causes damage to the tissues and organs, including the heart, lungs, skin, joints, blood vessels, liver kidney and nervous system.  Discoid lupus erythematosus is a form of lupus erythematosus that characterised by skin lesions caused deposition of autoantibodies and chronic inflammation of the skin but is not as serious as the systemic form.  Antimalarials like hydroxychloroquine in Plaquenil tablets 200mg have been found to have various immunomodulatory effects (ability to influence and modify the immune system) as well as antiinflamatory effects, and are classified as disease-modifying antirheumatic drug (DMARD).  There are several mechanisms by which hydroxychloroquine is thought to exert its beneficial effects. These include inhibition of inflammatory mediators such as interleukins and prostaglandins; also dampening down the immune response by interacting with immune cells that influence the immune response to autoantigens (directed against self) and by interfering with antigen-processing in antigen presenting cells like macrophages.  These combined actions of hydroxychloroquine in Plaquenil tablets 200mg help slow down the progression of chronic rheumatic diseases, such as acute and chronic arthritis and mild SLE and DLE. 

What are the side effects of Plaquenil?

The most commonly reported side effects when taking Plaquenil tablets 200mg include: abdominal pain, nausea, diarrhoea, vomiting, loss of appetite, headache, skin rash, pruritus (itching), vertigo, tinnitus, nerve deafness, nervousness, dizziness hair loss, blurring of vision.

When should Plaquenil not be used?

You should not use Plaquenil tablets 200mg if you:

• are allergic to hydroxychloroquine, quinine or other 4-aminoquinoline compounds or any ingredients in Plaquenil
• are pregnant or are breastfeeding
• have kidney or liver disease
• have any pre-existing eye disorders (ocular maculopathy)
• have severe gastrointestinal, neurological or blood disorders
• have the skin conditions porphyria (a genetic condition affecting haem production) or psoriasis (an immune mediated skin condition)
• have pre-existing maculopathy of the eye
• have glucose-6-phosphate dehydrogenase deficiency (G6PD), an inherited condition
• have QT prolongation, have irregular heart beat or other heart problems
• are taking medicines that interact with Plaquenil, including monoamine oxidase inhibitor antidepressants, digoxin for heart problems, anti-diabetic medications, antiarrhythmics like amiodarone and moxifloxacin, antiepileptic drugs, other anitmalarials, the immunosuppressant cyclosporine.

What medications interact with Plaquenil?

Several medications interact with Plaquenil tablets 200mg and should either not be taken while you are taking Plaquenil or only after discussion and instruction from your doctor:

• Drugs that cause a serious reaction with Plaquenil: monoamine oxidase inhibitor antidepressants, antiarrhythmics like amiodarone and moxifloxacin, other anitmalarials
• Drugs that are affected by Plaquenil: digoxin for heart problems, anti-diabetic medications, antiepileptic drugs, the immunosuppressant cyclosporine

How should Plaquenil be taken?

You should take your Plaquenil tablets 200mg with a glass and with food of water.  For rheumatoid arthritis, SLE and DLE you should take your Plaquenil tablets 200mg 2-4 times daily for several weeks as recommended by your doctor.  For prevention of malaria you should take your Plaquenil tablets 200mg once a week on the same day each week.  For the treatment of malaria you should take your Plaquenil tablets 200mg twice a day on the first day with 6-8 hours between doses and then on the next 2 consecutive days.  The dose you take, how often and for how long depends on what you are being treated for and your doctor’s recommendation.

How long should you take Plaquenil?

You should take your Plaquenil tablets 200mg for as long as recommended by your doctor, depending on what you are being treated for.

Missed dose of Plaquenil

If you miss a dose of Plaquenil take it as soon as you remember, unless it is time to take the next dose, then skip the missed dose.  Do not take a double dose.

How should Plaquenil be stored?

You should store your Plaquenil below 25°C in a cool dry place. 

Reference

Ben-Zvi I, Kivity S, Langevitz P Shoenfeld Y.  Hydroxychloroquine: from malaria to autoimmunity. Clin Rev Allergy Immunol. 2012; 42:145-53.  http://link.springer.com/article/10.1007/s12016-010-8243-x#page-2