Sulfamethoxazole and Trimethoprim

Pediatric Medication

Brand Names: US

Bactrim; Bactrim DS; Septra DS; Sulfatrim

Brand Names: Canada

Apo-Sulfatrim; Apo-Sulfatrim DS; Apo-Sulfatrim Pediatric; Protrin DF; Septra Injection; Teva-Trimel; Teva-Trimel DS; Trisulfa; Trisulfa DS; Trisulfa S

What is this drug used for?

  • It is used to treat or prevent bacterial infections.

What do I need to tell the doctor BEFORE my child takes this drug?

  • If your child has an allergy to this drug or any part of this drug.
  • If your child is allergic to any drugs like this one or any other drugs, foods, or other substances. Tell the doctor about the allergy and what signs your child had, like rash; hives; itching; shortness of breath; wheezing; cough; swelling of face, lips, tongue, or throat; or any other signs.
  • If your child has anemia caused by a lack of folic acid.
  • If your child has any of these health problems: Kidney disease or liver disease.
  • If your child has ever had a low platelet count when using trimethoprim or a sulfa (sulfonamide) drug.
This is not a list of all drugs or health problems that interact with this drug.
Tell the doctor and pharmacist about all of your child’s drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for your child to take this drug with all of his/her drugs and health problems. Do not start, stop, or change the dose of any drug your child takes without checking with the doctor.

What are some things I need to know or do while my child takes this drug?

All products:

  • Tell dentists, surgeons, and other doctors that your child is using this drug.
  • Have your child’s blood work checked often. Talk with your child’s doctor.
  • This drug may affect certain lab tests. Be sure the doctor and lab workers know your child takes this drug.
  • Do not give to your child longer than you have been told. A second infection may happen.
  • Talk with the doctor before your child gets any vaccines. Use with this drug may either raise the chance of very bad infection or make the vaccine not work as well.
  • Be careful if your child has G6PD deficiency. Anemia may happen.
  • If your child has high blood sugar (diabetes), you will need to watch his/her blood sugar closely.
  • Alcohol may interact with this drug. Be sure your child does not drink alcohol.
  • Your child may get sunburned more easily. Avoid lots of sun, sunlamps, and tanning beds. Use sunscreen and dress your child in clothing and eyewear that protects him/her from the sun.
  • Do not give this drug to an infant younger than 2 months of age.

If your child is pregnant or breast-feeding a baby:

  • This drug may cause harm to the unborn baby if your child takes it during pregnancy.
  • Talk with the doctor if your child is pregnant, becomes pregnant, or is breast-feeding a baby. You will need to talk about the benefits and risks of using this drug.


  • Some products have benzyl alcohol. Do not give a product that has benzyl alcohol in it to a newborn. Talk with the doctor to see if this product has benzyl alcohol in it.

What are some side effects that I need to call my child’s doctor about right away?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your child’s doctor or get medical help right away if your child has any of the following signs or symptoms that may be related to a very bad side effect:

All products:

  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
  • Signs of a high potassium level like a heartbeat that does not feel normal; change in thinking clearly and with logic; feeling weak, lightheaded, or dizzy; feel like passing out; numbness or tingling; or shortness of breath.
  • Not able to pass urine or change in how much urine is passed.
  • Muscle or joint pain.
  • Purple patches on the skin or mouth.
  • Shortness of breath.
  • It is common to have diarrhea when taking this drug. Rarely, a very bad form of diarrhea called Clostridium difficile (C diff)-associated diarrhea (CDAD) may occur. Sometimes, this has led to a deadly bowel problem (colitis). CDAD may happen while your child is taking this drug or within a few months after he/she stops taking it. Call your child’s doctor right away if your child has stomach pain or cramps, very loose or watery stools, or bloody stools. Do not try to treat loose stools without first checking with the doctor.
  • Very bad and rarely deadly effects have happened with sulfa (sulfonamide) drugs like this one. These effects have included liver problems, blood problems, and very bad skin reactions (Stevens-Johnson syndrome/toxic epidermal necrolysis). Call the doctor right away if your child has a rash; red, swollen, blistered, or peeling skin; red or irritated eyes; sores in the mouth, throat, nose, or eyes; fever, chills, or sore throat; cough that is new or worse; feeling very tired or weak; any bruising or bleeding; or signs of liver problems like dark urine, feeling tired, not hungry, upset stomach or stomach pain, light-colored stools, throwing up, or yellow skin or eyes.


  • Irritation where the shot is given.
  • Pain where the shot was given.

What are some other side effects of this drug?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your child’s doctor or get medical help if any of these side effects or any other side effects bother your child or do not go away:
  • Upset stomach or throwing up.
  • Loose stools (diarrhea).
  • Not hungry.
These are not all of the side effects that may occur. If you have questions about side effects, call your child’s doctor. Call your child’s doctor for medical advice about side effects.
You may report side effects to your national health agency.

How is this drug best given?

Give this drug as ordered by your child’s doctor. Read all information given to you. Follow all instructions closely.

All products:

  • To gain the most benefit, do not miss giving your child doses.
  • Give as you have been told, even if your child feels well.
  • Give this drug at the same time of day.
  • Have your child drink lots of noncaffeine liquids every day unless told to drink less liquid by your child’s doctor.

All oral products:

  • Give this drug with or without food. Give with food if it causes an upset stomach.
  • Give this drug with a full glass of water.

Liquid (suspension):

  • Shake well before use.
  • Measure liquid doses carefully. Use the measuring device that comes with this drug. If there is none, get an oral syringe, a dropper, a spoon, or a cup (only for older children) from your pharmacist.


  • It is given as a shot into a vein over a period of time.
  • Your child’s doctor may teach you how to give the shot.
  • Follow how to give closely if you are giving the shot at home.
  • Do not use if the solution is cloudy, leaking, or has particles.
  • Do not use if solution changes color.
  • Throw away needles in a needle/sharp disposal box. Do not reuse needles or other items. When the box is full, follow all local rules for getting rid of it. Talk with a doctor or pharmacist if you have any questions.

What do I do if my child misses a dose?

  • Give a missed dose as soon as you think about it.
  • If it is close to the time for your child’s next dose, skip the missed dose and go back to your child’s normal time.
  • Do not give 2 doses at the same time or extra doses.

How do I store and/or throw out this drug?

All oral products:

  • Store at room temperature.
  • Store in a dry place. Do not store in a bathroom.
  • Protect from light.


  • Most of the time, this drug will be given in a hospital or doctor’s office. If stored at home, follow how to store as you were told by the doctor.

All products:

  • Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
  • Check with your pharmacist about how to throw out unused drugs.

General drug facts

  • If your child’s symptoms or health problems do not get better or if they become worse, call your child’s doctor.
  • Do not share your child’s drug with others and do not give anyone else’s drug to your child.
  • Keep a list of all your child’s drugs (prescription, natural products, vitamins, OTC) with you. Give this list to your child’s doctor.
  • Talk with your child’s doctor before giving your child any new drug, including prescription or OTC, natural products, or vitamins.
  • Some drugs may have another patient information leaflet. If you have any questions about this drug, please talk with your child’s doctor, pharmacist, or other health care provider.
  • If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

Consumer Information Use and Disclaimer

This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using this medicine.

Last Reviewed Date



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Sulfamethoxazole and Trimethoprim
©2015 Memorial Sloan Kettering Cancer Center - Generated on October 13, 2015