How does it work?

Pyrimethamine belongs to a group of medications called the antimalarials. Dapsone has an antimalarial and an antileprotic action. This combination is used to prevent a person becoming infected with malaria. Malaria is caused by an organism which is classed as a protozoa and is a parasite which is carried by mosquitoes. During a bite from a mosquito, the parasite passes into the body. Once inside, it lives and reproduces. This results in the infection known as malaria. In the blood, malaria parasites break down a part of the red blood cells known as haemoglobin. When this happens haemoglobin is divided into two parts; haem and globin. Haem is toxic to the malaria parasite. To prevent it from being damaged, the malaria parasite produces an chemical which converts the toxic haem into a non-toxic compound. Pyrimethamine and dapsone both work by blocking the production of a chemical called folinic acid inside the parasite. Folinic acid is essential in the production of new genetic material (DNA). DNA is necessary for the parasite to reproduce, therefore by blocking it's formation this prevents the malarial parasites from increasing in number. When travelling to a part of the world where malaria is present it is important to avoid being bitten by mosquitoes, as well as taking preventitive medication for the recommended time period before and after travelling. Pyrimethamine with dapsone (Maloprim) is used together with chloroquine in the prevention of malaria in certain areas where there is a high risk of chloroquine resistant Plasmodium falciparum malaria. Pyrimethamine should not be used alone for prevention or in the treatment of an established malarial infection.

What is it used for?

Prevention of Plasmodium falciparum malaria

Warning!

This medicine may rarely cause a decrease in the normal amounts of blood cells in the blood. For this reason, if you experience any unexplained bruising, purple spots, bleeding, sore throat, mouth ulcers, high temperature (fever), feeling tired or general illness, you should consult your doctor immediately so that blood tests can be carried out to check for this.

It is recommended that regular blood tests are performed to check levels of the blood components.

To prevent malaria this medicine should be started preferably one week, but at least two days, before travelling to the malarious area. It should be taken regularly thoughout the stay and continued for four weeks after leaving the malarious area.

Adequate folate supplementation should be given to women who are pregnant.

Use with caution in

Heart disease

Kidney disease

Lack of the chemical G6PD in the blood (G6PD deficiency)

Liver disease

Lung disease

Not to be used in

Allergy to any sulphonamide medicine

Life long inherited blood diseases which can cause a variety of symptoms, including mental health problems (porphyrias)

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy. If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and Breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

This medicine should be used with caution during pregnancy, and only if the expected benefit to the mother is greater than the possible risk to the foetus, particularly in the first trimester. Seek medical advice from your doctor.

This medicine passes into breast milk. Seek medical advice from your doctor before using this medicine during breastfeeding.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

Rash

Difficulty in sleeping (insomnia)

Excessive breakdown of red blood cells that reduces red blood cell count (haemolytic anaemia)

Nausea and vomiting

Loss of appetite

Rash with a fever and a decrease in numbers of certain immune cells (Dapsone syndrome).

Inability of red blood cells to transport oxygen due to disorders of haemoglobin (methaemoglobinaemia)

Sudden severe deficiency in the number of white blood cells in the blood (agranulocytosis)

Decrease in the number of platelets in the blood (thrombocytopenia)

Anaemia where the cells in the bone marrow that are to form red blood cells are larger than normal, usually due to a deficiency in folic acid or vitamin B12 (megaloblastic anaemia)

Yellowing of the skin and eyes (jaundice)

Loss of contact with reality (psychosis)

Symptoms similar to Glandular Fever.

The side effects listed above may not include all of the side effects reported by the drug's manufacturer. For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

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