Who can and cannot take trimethoprim

Most adults and children can take trimethoprim.

Trimethoprim is not suitable for some people. To make sure it's safe for you, tell your doctor before starting to take trimethoprim if you:

• have ever had an allergic reaction to trimethoprim or any other medicine
• have liver or kidney problems
• have iron deficiency anaemia or low amounts of folic acid (vitamin B12 or folate deficiency anaemia) in your blood
• have porphyria (a rare inherited blood disorder) or any other blood disorder
• are trying to get pregnant or are already pregnant