Trimethoprim

About trimethoprim

Trimethoprim works by killing or stopping the growth of the bacteria responsible for the infection.

Before taking trimethoprim

Before taking trimethoprim make sure your doctor or pharmacist knows:

• If you are pregnant, trying for a baby or breast-feeding.
• If you have kidney problems.
• If you have porphyria or any other blood disorder.
• If you know you have low amounts of the vitamin folic acid.
• If you are taking other medicines, including those available to buy without a prescription, herbal or complementary medicines.
• If you have ever had an allergic reaction to this or any other medicine.

How to take trimethoprim

• Before beginning treatment, read the manufacturer's printed information leaflet.
• Take trimethoprim exactly as directed by your doctor.
• Try to take trimethoprim at the same times each day to keep a steady level of trimethoprim in your body and to avoid missing any doses. It is usually taken twice each day (in the morning and evening) to treat infections and once a day (at night) to prevent infections.
• If you forget to take a dose, take one as soon as you remember but do not take two doses at the same time.

Getting the most from your treatment

• Even if your condition has improved, it is important to complete the course of trimethoprim that you have been given. If you stop taking this medicine too soon your infection may come back and could be more difficult to treat.
• If you are having any treatment like an operation or dental treatment, tell the person carrying out the treatment which medicines you are taking.
• If you buy any medicines, check with a pharmacist that they are safe to take with your other medicines.

Can trimethoprim cause problems?

Along with their useful effects all medicines can cause unwanted side-effects. These usually improve as your body adjusts to the new medicine. Speak with your doctor or pharmacist if any of the following side-effects continue or become troublesome.

• An allergic reaction such as swelling of the mouth, face, tongue or throat with difficulty breathing.
• Severe skin rash with blisters.
• High temperature with a sore throat, mouth ulcers or unusual bruising or bleeding.
• Headache, fever, stiff neck, tiredness, feeling ill and an increased sensitivity to bright light.

If you experience any other symptoms which you think may be due to this medicine, speak with your doctor or pharmacist.

How to store trimethoprim

• Keep all medicines out of the reach and sight of children.
• Store in a cool, dry place, away from direct heat and light.

Important information about all medicines

References

• Manufacturer's PIL, Trimethoprim Tablets, Actavis UK Ltd, electronic Medicines Compendium. Dated March 2008, accessed December 2009.
• British National Formulary; 58th Edition (September 2009) British Medical Association and Royal Pharmaceutical Society of Great Britain, London (link to current BNF).