Trimethoprim is a prescription medication that is used to treat infections caused by certain bacteria including bladder infections, kidney infections, and ear infections. Trimethoprim is an antibiotic drug that works by preventing bacteria from growing.

Make sure to always read the patient information and instructions before using this medication. Always follow your doctor’s directions.

• This medication can be taken with or without food.
• Take trimethoprim at the same time each day.
• Take trimethoprim for the full length of time prescribed, even if your symptoms have cleared.

Tell your doctor and pharmacist:

• About your drug and other allergies.
• If you take any other prescription or over-the-counter medications.
• Your medical history particularly of liver disease, kidney disease, blood disorders, folate deficiency or anemia.
• If you are pregnant or planning pregnancy. This medication may affect an unborn baby’s development.

You should also know:

• It may not be safe to breast-feed while taking trimethoprim.
• Do not use anti-diarrhea medication to treat diarrhea without speaking to your doctor.

Common side effects of trimethoprim include but are not limited to:

• Stomach pain or diarrhea.
• Vomiting.
• Itching.

Get medical help if you have any of the following side effects of trimethoprim:

• Any skin rash.
• Grey or bluish skin.
• Fever or weakness.
• Bloody or watery diarrhea.
• Severe stomach pain.
• Sore or swollen tongue.
• Easy bruising.
• Red or purple spots under the skin.
• Signs of a high potassium level including chest pain, irregular heartbeats, loss of movement, nausea, weakness, or a tingly feeling.
• Symptoms of an allergic reaction such as difficulty breathing, hives, or swelling in your face, lips, or throat.

What should I do if I miss a dose of trimethoprim?

If you miss a dose of trimethoprim, you should take it as soon as you remember. However, if it is almost time for your next dose, then skip your missed dose.

What is the strength of trimethoprim?

Trimethoprim is available in strengths of 100mg and 200mg.