NZ Formulary

Trimethoprim

try-meth-oh-prim

What does it do?

Trimethoprim is an antibiotic used to treat and prevent urine infections, often called UTIs (urinary tract infections).

Before you start

  • Tell your health professional if you have kidney or blood problems.
  • Tell your health professional if you are pregnant, planning to become pregnant, or breastfeeding.

How should you take it?

Take trimethoprim regularly as directed with a glass of water. You can take it with or without food. Keep taking it until the course is finished, even if you start to feel better.

What if you forget a dose?

Take the missed dose as soon as possible and continue as directed.

Can you take other medicines?

Some medicines available without a prescription may react with trimethoprim including:

  • potassium supplements (e.g. Span K®)

Tell your pharmacist or doctor about all medicines or treatments that you may be taking, including vitamins, herbal products or recreational drugs.

Important information continues on next page.

What side effects might you notice?

Side EffectsRecommended action

Skin rash, skin peeling or blisters

Stop taking and see your doctor immediately

Severe headache, stiff neck, confusion, eyes sensitive to light

Reduced number of blood cells that fight infections or help your blood to clot - symptoms include: fever, chills, sore throat or generally feeling unwell, or easy or unusual bruising or bleeding

Tell your doctor immediately

Changes in heartbeat, muscle cramps or weakness

Tell your doctor

Stomach upset

Tell your health professional if troublesome

If you notice any other effects, discuss them with your doctor or pharmacist.