Taking trimethoprim with other medicines and herbal supplements

Some medicines affect the way trimethoprim works and increase the chances of you having side effects.

Check with a pharmacist or your doctor if you're taking any other medicines, including:

• rifampicin, an antibiotic
• warfarin or acenocoumarol (Sinthrome), medicines to treat or help prevent blood clots (anticoagulants)
• digoxin, a heart medicine
• phenytoin, an epilepsy medicine
• replaglinide or pioglitazone, diabetes medicines
• methotrexate, an immune system medicine, also used to treat some types of cancer

These are not all the medicines that may cause problems if you take them with trimethoprim. For a full list, see the leaflet inside your medicine packet.

Tell your doctor if you've recently had, or are due to have, an oral typhoid vaccine. Trimethoprim can make it less effective.