Sulfamethoxazole-trimethoprim

What is sulfamethoxazole-trimethoprim?

Sulfamethoxazole-trimethoprim is a medicine called an antibiotic. Antibiotics are used to treat or prevent certain types of infections caused by bacteria.

Sulfamethoxazole-trimethoprim is made up of 2 medicines, sulfamethoxazole and trimethoprim.

You may hear sulfamethoxazole-trimethoprim called by its brand names, Septra, Bactrim, Apo-Sulfatrim, or Novo-Trimel. Sulfamethoxazole-trimethoprim comes in tablet and liquid form.

Before giving sulfamethoxazole-trimethoprim to your child

Tell the doctor if your child has:

• an allergy to sulfonamides or sulfa drugs
• an allergy to trimethoprim

Talk with the doctor or pharmacist if your child has any of the following conditions. Precautions may need to be taken with this medicine if your child has:

• anemia or other blood problems
• glucose-6-phosphate dehydrogenase (G6PD) deficiency
• kidney disease
  
• liver disease
• porphyria

How should you give your child sulfamethoxazole-trimethoprim?

Follow these instructions when giving your child sulfamethoxazole-trimethoprim:

• Give your child sulfamethoxazole-trimethoprim for as long as the doctor or pharmacist tells you, even if your child seems better. Talk to your child's doctor before you stop giving sulfamethoxazole-trimethoprim for any reason.
• Give your child sulfamethoxazole-trimethoprim at the same times of the day, exactly as your child's doctor or pharmacist tells you. Pick a time that is easy for you so that you do not miss doses.
• Give your child sulfamethoxazole-trimethoprim with a full glass of water or other liquid. Get your child to drink plenty of fluids such as water, juice, or milk while they are taking sulfamethoxazole-trimethoprim.
• Your child may take sulfamethoxazole-trimethoprim with or without food. It may be given with food or milk if it upsets your child's stomach.
• If your child is taking liquid sulfamethoxazole-trimethoprim, shake the bottle well. Use the special spoon or syringe that the pharmacist gave you to measure and give the dose.

What should you do if your child misses a dose of sulfamethoxazole-trimethoprim?

• Give the missed dose as soon as you remember.
• If it is almost time for the next dose, skip the missed dose. Give the next dose at the regular time.
• Do not give your child two doses to make up for one missed dose.

How long does sulfamethoxazole-trimethoprim take to work?

Your child may begin to feel better a few days after starting sulfamethoxazole-trimethoprim.

What are the possible side effects of sulfamethoxazole-trimethoprim?

Your child may have some of these side effects while they take sulfamethoxazole-trimethoprim. Check with your child's doctor if your child continues to have any of these side effects and they do not go away or they bother your child:

• upset stomach
• diarrhea (loose, watery stools)
• vomiting (throwing up)
• loss of appetite
• headache
• dizziness

Call your child's doctor during office hours if your child has any of these side effects:

• increased sensitivity of skin to sun
• a pain or burning feeling when your child urinates that is new or does not get better

Most of the following side effects are not common, but they may be a sign of a serious problem. Call your child's doctor right away or take your child to the Emergency Department if your child has any of these side effects:

• severe skin rash (rash covering large part of body, with fever or blisters)
• hives (raised, red itchy areas on the skin)
• yellowing of the eyes or skin
• unusual bruising or bleeding
• swelling of the face, lips, tongue, throat
• trouble breathing

What safety measures should you take when your child is using sulfamethoxazole-trimethoprim?

Before your child has any kind of operation, even on the teeth, or an emergency treatment, tell the doctor or dentist that your child is taking sulfamethoxazole-trimethoprim.

Check with your child's doctor or pharmacist before giving your child any other medicines (prescription, non-prescription, herbal, or natural products).

sulfamethoxazole-trimethoprim may make your child's skin more likely to sunburn. To help prevent sunburn:

• Avoid direct sunlight for long periods of time.
• When outside, cover your child with clothing and a hat.
• Apply a sunscreen with an SPF of 15 or higher.
• Avoid sunlamps and tanning beds.

What other important information should you know about sulfamethoxazole-trimethoprim?

• Keep a list of all medications your child is on and show the list to the doctor or pharmacist.
• Do not share your child's medicine with others and do not give anyone else's medicine to your child.
• Make sure you always have enough sulfamethoxazole-trimethoprim to last through weekends, holidays, and vacations. Call your pharmacy at least 2 days before your child runs out of medicine to order refills.
• Keep sulfamethoxazole-trimethoprim tablets and liquid at room temperature in a cool, dry place away from sunlight. Do not store it in the bathroom or kitchen.
• Do not keep any medicines that are out of date. Check with your pharmacist about the best way to throw away outdated or leftover medicines.

Keep cotrimoxazole out of your child’s sight and reach and locked up in a safe place. If your child takes too much cotrimoxazole, call your local Poison Information Centre at one of these numbers. These calls are free. 

• Call 1-844 POISON-X, or 1-844-764-7669, from anywhere in Canada except Quebec.
• Call 1-800-463-5060 if you live in Quebec.