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sulfamethoxazole and trimethoprim

Pronunciation

Generic Name: sulfamethoxazole and trimethoprim (SUL fa meth OX a zole and trye METH oh prim)
Brand Name: Bactrim, Bactrim DS, Septra DS, SMZ-TMP DS, ...show all 18 brand names

What is sulfamethoxazole and trimethoprim?

Sulfamethoxazole and trimethoprim are both antibiotics that treat different types of infection caused by bacteria.

Sulfamethoxazole and trimethoprim is used a combination antibiotic used to treat ear infections, urinary tract infections, bronchitis, traveler's diarrhea, shigellosis, and Pneumocystis jiroveci pneumonia.

Sulfamethoxazole and trimethoprim may also be used for purposes not listed in this medication guide.

What is the most important information I should know about sulfamethoxazole and trimethoprim?

You should not use this medication if you have severe liver or kidney disease, anemia caused by folic acid deficiency, or a history of low blood platelets caused by taking trimethoprim or any sulfa drug.

What should I discuss with my healthcare provider before taking sulfamethoxazole and trimethoprim?

You should not use this medication if you are allergic to sulfamethoxazole or trimethoprim, or if you have:

  • severe liver or kidney disease;

  • anemia (low red blood cells) caused by folic acid deficiency; or

  • a history of low blood platelets caused by taking trimethoprim or any sulfa drug.

To make sure sulfamethoxazole and trimethoprim is safe for you, tell your doctor if you have:

  • kidney or liver disease;

  • a folic acid deficiency;

  • asthma or severe allergies;

  • a thyroid disorder;

  • HIV or AIDS;

  • porphyria (a genetic enzyme disorder that causes symptoms affecting the skin or nervous system);

  • a glucose-6-phosphate dehydrogenase deficiency (G6PD deficiency); or

  • if you are malnourished.

FDA pregnancy category D. Do not use sulfamethoxazole and trimethoprim if you are pregnant. It could harm the unborn baby. Use effective birth control, and tell your doctor if you become pregnant during treatment.

This medicine can pass into breast milk and may harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

Do not give this medication to a child younger than 2 months old.

Serious side effects may be more likely in older adults, especially those who take other medications such as digoxin or certain diuretics.

How should I take sulfamethoxazole and trimethoprim?

Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Shake the oral suspension (liquid) well just before you measure a dose. Measure the liquid with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.

Use this medication for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Skipping doses may also increase your risk of further infection that is resistant to antibiotics. Sulfamethoxazole and trimethoprim will not treat a viral infection such as the common cold or flu.

Drink plenty of fluids to prevent kidney stones while you are taking trimethoprim and sulfamethoxazole.

This medication can cause unusual results with certain medical tests. Tell any doctor who treats you that you are using sulfamethoxazole and trimethoprim.

Store at room temperature away from moisture, heat, and light.

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking sulfamethoxazole and trimethoprim?

Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or bloody, stop taking this medication and call your doctor. Do not use anti-diarrhea medicine unless your doctor tells you to.

Avoid exposure to sunlight or tanning beds. This medication can make you sunburn more easily. Wear protective clothing and use sunscreen (SPF 30 or higher) when you are outdoors.

Sulfamethoxazole and trimethoprim side effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • diarrhea that is watery or bloody;

  • pale skin, feeling light-headed or short of breath, rapid heart rate, trouble concentrating;

  • sudden weakness or ill feeling, fever, chills, sore throat, new or worsening cough;

  • cold or flu symptoms, swollen gums, painful mouth sores, pain when swallowing, skin sores;

  • low levels of sodium in the body--headache, confusion, slurred speech, severe weakness, vomiting, loss of coordination, feeling unsteady;

  • liver problems--upper stomach pain, tired feeling, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or

  • severe skin reaction--fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain, followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.

Common side effects may include:

  • nausea, vomiting, loss of appetite; or

  • mild itching or rash.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Sulfamethoxazole and trimethoprim dosing information

Usual Adult Dose for Pneumocystis Pneumonia:

Oral: 15 to 20 mg/kg/day (based on the trimethoprim component) orally daily in 4 equally divided doses every 6 hours for 14 to 21 days

IV: 15 to 20 mg/kg/day (based on the trimethoprim component) IV daily in 3 or 4 equally divided doses every 6 to 8 hours for up to 14 days

Comments:
-IV formulation: One investigator noted that a total daily dose of 10 to 15 mg/kg was sufficient in 10 adult patients with normal renal function.

Use: For the treatment of documented Pneumocystis jiroveci pneumonia

Usual Adult Dose for Pneumocystis Pneumonia Prophylaxis:

-Sulfamethoxazole-trimethoprim 800 mg-160 mg (1 double strength tablet) orally once a day
-Maximum dose: The total daily dose should not exceed 1600 mg sulfamethoxazole and 320 mg trimethoprim

Use: For prophylaxis against P jiroveci pneumonia in individuals who are immunosuppressed and considered to be at an increased risk of developing P jiroveci pneumonia

Usual Adult Dose for Urinary Tract Infection:

Oral: Sulfamethoxazole-trimethoprim 800 mg-160 mg orally every 12 hours for 10 to 14 days

IV:
Severe infection: 8 to 10 mg/kg/day (based on the trimethoprim component) IV in 2 to 4 equally divided doses every 6, 8, or 12 hours for up to 14 days; maximum recommended dose is 960 mg (based on the trimethoprim component) per day

Use: For the treatment of severe or complicated urinary tract infections due to susceptible strains of Escherichia coli, Klebsiella species, Enterobacter species, Morganella morganii, Proteus mirabilis, and Proteus vulgaris

Usual Adult Dose for Shigellosis:

Oral: Sulfamethoxazole-trimethoprim 800 mg-160 mg (1 double strength tablet or 2 single strength tablets) orally every 12 hours for 5 days

IV:
Severe infection: 8 to 10 mg/kg/day (based on the trimethoprim component) IV in 2 to 4 equally divided doses every 6, 8, or 12 hours for 5 days; maximum recommended dose is 960 mg (based on the trimethoprim component) per day

Comments:
-The patient should be instructed to use extraordinary sanitary precautions since Shigella is transmitted by the fecal-oral route, primarily by hand-to-mouth contact.

Use: For the treatment of enteritis caused by susceptible strains of Shigella flexneri and Shigella sonnei

Usual Adult Dose for Bronchitis:

Sulfamethoxazole-trimethoprim 800 mg-160 mg (1 double strength tablet or 2 single strength tablets) orally every 12 hours for 14 days

Use: For acute exacerbations of chronic bronchitis due to susceptible strains of Streptococcus pneumoniae or Haemophilus influenzae when the physician deems that sulfamethoxazole and trimethoprim could offer some advantage over the use of a single antimicrobial agent

Usual Adult Dose for Traveler's Diarrhea:

Sulfamethoxazole-trimethoprim 800 mg-160 mg (1 double strength tablet or 2 single strength tablets) orally every 12 hours for 5 days

Use: For the treatment of traveler's diarrhea due to susceptible strains of enterotoxigenic E coli

Usual Adult Dose for Pyelonephritis:

Uncomplicated: Sulfamethoxazole-trimethoprim 800 mg-160 mg (1 double strength tablet) orally every 12 hours for 10 days

Use: Uncomplicated pyelonephritis (off-label use)

Usual Adult Dose for Otitis Media:

Sulfamethoxazole-trimethoprim 800 mg-160 mg (1 double strength tablet) orally every 12 hours for 10 to 14 days

Use: Otitis media (off-label use in adults)

Usual Adult Dose for Cystitis Prophylaxis:

Sulfamethoxazole-trimethoprim 400 mg-80 mg (1 single-strength tablet) orally once a day or 3 times a week at bedtime

Comments:
-Some clinicians recommend that their female patients take this low dose postcoitally or 3 times a week, whichever is less frequent. Therapy should be continued for as long as the patient is at risk for infection.

Use: Cystitis prophylaxis (off-label use)

Usual Adult Dose for Granuloma Inguinale:

Sulfamethoxazole-trimethoprim 800 mg-160 mg (1 double strength tablet) orally 2 times a day for at least 3 weeks

Use: Granuloma inguinale (off-label use)

Usual Adult Dose for Meningitis:

10 to 20 mg/kg (based on the trimethoprim component) IV every 6 to 12 hours

Comments:
Use in combination with chloramphenicol is an alternative for patients with beta-lactam allergy

Use: Bacterial meningitis (off-label use)

Usual Adult Dose for Nocardiosis:

Cutaneous infection: 5 to 10 mg/kg/day (based on the trimethoprim component) IV or orally in 2 to 4 divided doses

Severe infection (pulmonary/cerebral): 15 mg/kg/day (based on the trimethoprim component) in 2 to 4 divided doses for 3 to 4 weeks, then 10 mg/kg/day (based on the trimethoprim component) in 2 to 4 divided doses; may be initiated IV and converted to oral therapy (frequently converted to approximate dosages of oral solid dosage forms: 2 double strength tablets [320 mg-1600 mg] every 8 to 12 hours)

Duration: Not well standardized; most experts recommend at least 6 months for local disease in immunocompetent patients and 6 to 12 months or more for immunocompromised patients or patients with CNS disease

Comments:
-Off-label use.
-Measurement of serum levels are advisable. Maximum plasma concentrations (Cmax) of 100 to 150 mcg/mL are recommended. Severe disease is often treated with addition of other agents, such as ceftriaxone, imipenem, or amikacin.

Usual Adult Dose for Prostatitis:

Sulfamethoxazole-trimethoprim 800 mg-160 mg (1 double strength tablet) orally every 12 hours

Duration: Acute, 10 to 14 days; chronic, 1 to 3 months

Comments:
-Off-label use.

Usual Adult Dose for Sinusitis:

Sulfamethoxazole-trimethoprim 800 mg-160 mg (1 double strength tablet) orally every 12 hours

Duration: 10 to 14 days; in some cases of recurrent or refractory sinusitis, therapy may be required for up to 3 to 4 weeks

Comments:
-Off-label use.

Usual Adult Dose for Toxoplasmosis:

5 mg/kg (based on the trimethoprim component) IV every 12 hours

Duration: 4 weeks to 6 months or more, depending on the nature and severity of the infection; patients with AIDS are usually given high dose therapy for 4 to 6 weeks then maintained on oral trimethoprim-sulfamethoxazole for life

Comments:
-Off-label use.

Usual Adult Dose for Toxoplasmosis -- Prophylaxis:

Acute bacterial exacerbation of chronic bronchitis: Trimethoprim-sulfamethoxazole 160 mg-800 mg (1 double-strength tablet) orally every 12 hours for 14 days

Usual Adult Dose for Upper Respiratory Tract Infection:

Sulfamethoxazole-trimethoprim 800 mg-160 mg (1 double strength tablet) orally every 12 hours

Comments:
-Off-label use.

Usual Pediatric Dose for Otitis Media:

2 months or older:
4 mg/kg (based on the trimethoprim component) orally every 12 hours for 10 to 14 days

Use: For the treatment of acute otitis media in pediatric patients due to susceptible strains of Streptococcus pneumoniae or Haemophilus influenzae when in the judgment of the physician sulfamethoxazole and trimethoprim offers some advantage over the use of other antimicrobial agents; sulfamethoxazole and trimethoprim is not indicated for prophylactic or prolonged administration in otitis media

Usual Pediatric Dose for Urinary Tract Infection:

2 months or older:
-Oral: 4 mg/kg (based on the trimethoprim component) orally every 12 hours for 10 to 14 days
-IV:
Severe infection: 8 to 10 mg/kg/day (based on the trimethoprim component) IV in 2 to 4 equally divided doses every 6, 8, or 12 hours for 10 to 14 days; maximum recommended dose is 960 mg (based on the trimethoprim component) per day

Use: For the treatment of severe or complicated urinary tract infections due to susceptible strains of Escherichia coli, Klebsiella species, Enterobacter species, Morganella morganii, Proteus mirabilis, and Proteus vulgaris

Usual Pediatric Dose for Shigellosis:

2 months or older:
-Oral: 4 mg/kg (based on the trimethoprim component) orally every 12 hours for 5 days
-IV:
Severe infection: 8 to 10 mg/kg/day (based on the trimethoprim component) IV in 2 to 4 equally divided doses every 6, 8, or 12 hours for 5 days; maximum recommended dose is 960 mg (based on the trimethoprim component) per day

Comments:
-The patient should be instructed to use extraordinary sanitary precautions since Shigella is transmitted by the fecal-oral route, primarily by hand-to-mouth contact.

Use: For the treatment of enteritis caused by susceptible strains of Shigella flexneri and Shigella sonnei

Usual Pediatric Dose for Pneumocystis Pneumonia:

2 months or older:
15 to 20 mg/kg/day (based on the trimethoprim component) orally or IV every 24 hours given in 4 equally divided doses every 6 hours for 14 to 21 days

Use: For the treatment of documented Pneumocystis jiroveci pneumonia

Usual Pediatric Dose for Pneumocystis Pneumonia Prophylaxis:

2 months or older:
75 mg/m2 (based on the trimethoprim component) orally 2 times a day, on 3 consecutive days per week

Maximum dose: The total daily dose should not exceed 320 mg (based on the trimethoprim component)

Use: For prophylaxis against P. jiroveci pneumonia in individuals who are immunosuppressed and considered to be at an increased risk of developing P jiroveci pneumonia

What other drugs will affect sulfamethoxazole and trimethoprim?

Tell your doctor about all medicines you use, and those you start or stop using during your treatment with sulfamethoxazole and trimethoprim, especially:

  • leucovorin; or

  • methotrexate.

This list is not complete. Other drugs may interact with sulfamethoxazole and trimethoprim, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.

See also: Side effects (in more detail)

Where can I get more information?

  • Your pharmacist can provide more information about sulfamethoxazole and trimethoprim.
  • Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
  • Disclaimer: Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2012 Cerner Multum, Inc. Version: 8.01.

Date modified: October 13, 2017
Last reviewed: December 15, 2013

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