Pronounced: BAC-trim
Generic ingredients : Trimethoprim, Sulfamethoxazole
Brand names : Septra

Bactrim - Indications :
Bactrim, an antibacterial combination drug, is prescribed for the treatment of certain urinary tract infections, severe middle ear infections in children, long-lasting or frequently recurring bronchitis in adults that has increased in seriousness, inflammation of the intestine due to a severe bacterial infection, and travelers’ diarrhea in adults. Bactrim is also prescribed for the treatment ofPneumocystis cariniipneumonia, and for prevention of this type of pneumonia in people with weakened immune systems.

More information on Bactrim :
Sulfamethoxazole, an ingredient in Bactrim, is one of a group of drugs called sulfonamides, which prevent the growth of bacteria in the body. Rare but sometimes fatal reactions have occurred with use of sulfonamides. These reactions include Stevens-Johnson syndrome (severe eruptions around the mouth, anus, or eyes), progressive disintegration of the outer layer of the skin, sudden and severe liver damage, a severe blood disorder (agranulocytosis), and a lack of red and white blood cells because of a bone marrow disorder.

Notify your doctor at the first sign of an adverse reaction such as skin rash, sore throat, fever, joint pain, cough, shortness of breath, abnormal skin paleness, reddish or purplish skin spots, or yellowing of the skin or whites of the eyes.

Frequent blood counts by a doctor are recommended for patients taking sulfonamide drugs.

How to take Bactrim :
It is important that you drink plenty of fluids while taking this medication in order to prevent sediment in the urine and the formation of stones.

Bactrim works best when there is a constant amount in the blood. Take Bactrim exactly as prescribed; try not to miss any doses. It is best to take doses at evenly spaced times day and night.

If you are taking Bactrim suspension, ask your pharmacist for a specially marked measuring spoon that delivers accurate doses.

Missed dose : Take the forgotten dose as soon as you remember. If it is almost time for your next dose, skip the one you missed and go back to your regular schedule. Do not take 2 doses at once.

Storage : Store tablets and suspension at room temperature and protect from light. Keep tablets in a dry place. Protect the suspension from freezing.

Bactrim - Possible side effects :
Every medicine can cause certain side effects. If any develop or change in intensity, inform your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking Bactrim.

  • More common side effects may include : Hives, lack or loss of appetite, nausea, skin rash, vomiting  
  • Less common or rare side effects may include : Abdominal pain, allergic reactions, anemia, chills, convulsions, depression, diarrhea, eye irritation, fatigue, fever, hallucinations, headache, hepatitis, inability to fall or stay asleep, inability to urinate, increased urination, inflammation of heart muscle, inflammation of the mouth and/or tongue, itching, joint pain, kidney failure, lack of feeling or concern, lack of muscle coordination, loss of appetite, low blood sugar, meningitis (inflammation of the brain or spinal cord), muscle pain, nausea, nervousness, red, raised rash, redness and swelling of the tongue, ringing in the ears, scaling of dead skin due to inflammation, sensitivity to light, severe skin welts or swelling, skin eruptions, skin peeling, vertigo, weakness, yellowing of eyes and skin

Bactrim - Contraindications :
If you are sensitive to or have ever had an allergic reaction to trimethoprim, sulfamethoxazole, or other sulfa drugs, you should not take this medication. Make sure that your doctor is aware of any drug reactions that you have experienced.

Unless you are directed to do so by your doctor, do not take this medication if you have been diagnosed as having megaloblastic anemia, which is a blood disorder due to a deficiency of folic acid.

This drug should not be given to infants less than 2 months of age.

Bactrim is not recommended for preventative or prolonged use in middle ear infections and should not be used in the treatment of streptococcal pharyngitis (strep throat) or certain other strep infections.

You should not take Bactrim if you are pregnant or nursing a baby.

Bactrim - Warnings :
Make sure your doctor knows if you have impaired kidney or liver function, have a folic acid deficiency, are a chronic alcoholic, are taking anticonvulsants, have been diagnosed as having malabsorption syndrome (abnormal intestinal absorption), are in a state of poor nutrition, or have severe allergies or bronchial asthma. Bactrim should be used cautiously under these conditions.

If you develop severe diarrhea, call your doctor. This drug can cause a serious intestinal inflammation.

If you have AIDS (acquired immunodeficiency syndrome) and are taking Bactrim to treat or preventPneumocystis cariniipneumonia, you will experience more side effects than will someone without AIDS.

Bactrim - Food and drug interactions :
If Bactrim is taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining Bactrim with the following:

Amantadine (Symmetrel)
Blood thinners such as Coumadin
Cyclosporine ( Neoral, Sandimmune )
Digoxin ( Lanoxin )
Indomethacin ( Indocin )
Methotrexate ( Rheumatrex )
Oral diabetes medications such as Micronase and Glucotrol
Pyrimethamine (Daraprim)
Seizure medications such as Dilantin
Tricyclic antidepressants such as Elavil, Norpramin, Sinequan, and Tofranil
Water pills (diuretics) such as HydroDIURIL

Bactrim - Pregnant and breastfeeding women :
Bactrim should not be taken during pregnancy. If you are pregnant or plan to become pregnant, notify your doctor immediately. Bactrim does appear in breast milk and could affect a nursing infant. It should not be taken while breastfeeding.

Bactrim - Dosage :

Adults : Urinary Tract Infections and Intestinal Inflammation

The usual adult dosage in the treatment of urinary tract infection is 1 Bactrim DS (double strength tablet) or 2 Bactrim tablets, or 4 teaspoonfuls (20 ml) of Bactrim Pediatric Suspension every 12 hours for 10 to 14 days. The dosage for inflammation of the intestine is the same but is taken for 5 days.

Worsening of Chronic Bronchitis

The usual recommended dosage is 1 Bactrim DS (double strength tablet), 2 Bactrim tablets, or 4 teaspoonfuls (20 ml) of Bactrim Pediatric Suspension every 12 hours for 14 days.

Treatment of Pneumocystis Carinii Pneumonia

The recommended dosage is 15 to 20 mg of trimethoprim and 75 to 100 mg of sulfamethoxazole per 2.2 pounds of body weight per 24 hours divided into equal doses every 6 hours for 14 to 21 days.

Prevention of Pneumocystis Carinii Pneumonia

The recommended dosage is 1 Bactrim DS (double strength tablet) once daily.

Travelers’ Diarrhea

The usual recommended dosage is 1 Bactrim DS (double strength tablet), 2 Bactrim tablets, or 4 teaspoonfuls (20 ml) of Bactrim Pediatric Suspension every 12 hours for 5 days.

Children :Urinary Tract Infections or Middle Ear Infections

The recommended dosage for children 2 months of age or older, given every 12 hours for 10 days, is determined by weight. The following table is a guideline for this dosage:

22 pounds, 1 teaspoonful (5 ml)
44 pounds, 2 teaspoonfuls (10 ml) or 1 tablet
66 pounds, 3 teaspoonfuls (15 ml) or one-and-a-half tablets
88 pounds, 4 teaspoonfuls (20 ml) or 2 tablets or 1 DS tablet

Intestinal Inflammation

The recommended dosage is identical to the dosage recommended for urinary tract and middle ear infections; however, it should be taken for 5 days.

Treatment of Pneumocystis Carinii Pneumonia

The recommended dosage, taken every 6 hours for 14 to 21 days, is determined by weight. The following table is a guideline for this dosage:

18 pounds, 1 teaspoonful (5 ml)
35 pounds, 2 teaspoonfuls (10 ml) or 1 tablet
53 pounds, 3 teaspoonfuls (15 ml) or one-and-a-half tablets
70 pounds, 4 teaspoonfuls (20 ml) or 2 tablets or 1 DS tablet

Prevention of Pneumocystis Carinii Pneumonia

The recommended dosage, taken twice a day, on 3 consecutive days per week, is determined by body surface area. The total daily dose should not exceed 320 mg trimethoprim and 1600 mg sulfamethoxazole.

The safety of repeated use of Bactrim in children under 2 years of age has not been established.

Elderly adults : There may be an increased risk of severe side effects when Bactrim is taken by older people, especially in those who have impaired kidney and/or liver function or who are taking other medication. Consult with your doctor before taking Bactrim.
Bactrim - Overdose :

If you suspect an overdose of Bactrim, seek emergency medical attention immediately.


  • Symptoms of an overdose of Bactrim include : Blood or sediment in the urine, colic, confusion, dizziness, drowsiness, fever, headache, lack or loss of appetite, mental depression, nausea, unconsciousness, vomiting, yellowed eyes and skin

Johns Hopkins patient information

Copyright 1996-2014 Cerner Multum, Inc. Version: 16.02.
Revision date: July 7, 2011
Last revised: by Tatiana Kuznetsova, D.M.D.

Drugs & Medications

  A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.

The drug reference included in this section is provided by Cerner Multum, Inc., of Denver, Colorado. Armenian Medical Network receives monthly updates from Multum.