Pyrimethamine - oral

Patient Medicine Information
Why do I need this medicine?
Pyrimethamine is used together with other medicines for the treatment and prevention of malaria. It may also be used to treat certain infections caused by bacteria, parasites and fungi.
How do I take this medicine?
Take Pyrimethamine exactly as directed by your doctor or according to the instructions on the label. Do not take more or less than instructed by your doctor.

This medicine should be taken with food or immediately after a meal to minimise stomach discomfort.

Take Pyrimethamine at regular intervals for it to be effective. Continue taking this medicine even when you feel better. Do not stop taking it unless instructed by the doctor.

Do not skip any doses. To clear the infection, you must complete the entire course of this medicine. If you don't, the infection will not clear completely.
What should I do if I have forgotten to take this medicine?
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and return to your normal dosing schedule.

DO NOT double a dose under any circumstances.

If you often forget to take your medicine, let your doctor and pharmacist know.
When should I not use this medicine?
Alert your doctor if you have a blood disorder called “megaloblastic anaemia”, as Pyrimethamine may not be suitable for you.
What should I take note of while taking this medicine?
Inform your doctor if you have the following conditions:

- liver disease
- kidney disease
- epilepsy (fits or seizures)
- G6PD deficiency (an inherited blood disorder that affects the red blood cell)

Let your doctor know if you are pregnant or breastfeeding.

For as long as you are taking Pyrimethamine, you will need to have regular blood tests to check your body's response to the medicine. Your doctor will advise you about how often you need to have blood tests.

Your doctor may also give you some folic acid tablets to prevent blood disorders that may occur in people taking high doses of this medicine.
What side effects could I experience?
Pyrimethamine may cause dizziness. If affected, do not drive or take part in any activity in which you need to be alert.

Other side effects include any of the following: headache, stomach discomfort, nausea, vomiting and loss of appetite.

Some side effects my need immediate medical help. Alert your doctor quickly if you experience sore throat, pale appearance, bruising, shortness of breath, yellowing of the skin, inflammation or redness of the tongue.

Inform your doctor if any of these side effects do not go away or are severe, or if you experience other side effects.
Can I take this with other medicines?
Inform your doctor and pharmacist if you are taking any of these medicines:

- medicines for epilepsy (fits or seizures) e.g. phenytoin
- antibiotics e.g. co-trimoxazole, sulfadiazine
- medicines for mood disorders e.g. lorazepam
- other medicines to treat malaria e.g. quinine
- medicines to treat viral infections e.g. zidovudine
- warfarin (blood-thinning medicine)

This list does not include all medicines that may interact with Pyrimethamine.

Always notify your doctor and pharmacist if you are taking any other medicines, including herbal tonics such as traditional Chinese medicines, supplements and medicines that you buy without a prescription.
What special dietary instructions should I follow?
Avoid alcohol.
How should I store this medicine?
Store in a cool, dry place away from the reach of children.

Medicines must not be used past the expiry date.
This information is independently developed by MIMS based on pyrimethamine - oral and is provided for your reference only. It is not a replacement for and should only be used in conjunction with full consultation with a licensed healthcare professional, the information provided by your pharmacist and/or the manufacturer of the medication. It may not contain all the available information you require and cannot substitute professional medical care, nor does it take into account all individual circumstances. Although great effort has been made to ensure content accuracy, we shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 MIMS. All rights reserved. Powered by
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