trimethoprim

Generic Name: trimethoprim (trye METH oh prim)

Brand names: Primsol, Proloprim, Trimpex

What is trimethoprim?

Trimethoprim is an antibiotic that fights bacteria in the body.

Trimethoprim is used to treat bladder infection caused by certain bacteria.

Trimethoprim may also be used for other purposes not listed in this medication guide.

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

You should not use this medication if you are allergic to trimethoprim, or if you have any type of anemia (lack of red blood cells).

Before using trimethoprim, tell your doctor if you have kidney disease, liver disease, or a folic acid deficiency.

Take this medication for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Trimethoprim will not treat a viral infection such as the common cold or flu. Avoid exposure to sunlight or artificial UV rays (sunlamps or tanning beds). Trimethoprim can make your skin more sensitive to sunlight and sunburn may result. Use a sunscreen (minimum SPF 15) and wear protective clothing if you must be out in the sun.

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

You should not use this medication if you are allergic to trimethoprim, or have certain conditions. Be sure your doctor knows if you have any type of anemia (lack of red blood cells).

Before using trimethoprim, tell your doctor if you are allergic to any drugs, or if you have:

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  kidney disease;

  
  


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  liver disease; or

  
  


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  a folate (folic acid) deficiency.

  
  

If you have any of these conditions, you may need a dose adjustment or special tests to safely use trimethoprim.

FDA pregnancy category C. This medication may be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment. Trimethoprim can pass into breast milk and may harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

How should I take trimethoprim?

Take this medication exactly as prescribed by your doctor. Do not take it in larger amounts or for longer than recommended. Follow the directions on your prescription label.

Take your medicine with a full glass of water.

Measure liquid medicine with a special dose-measuring spoon or cup, not a regular table spoon. If you do not have a dose-measuring device, ask your pharmacist for one.

Take this medication for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Trimethoprim will not treat a viral infection such as the common cold or flu.

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

Store trimethoprim at room temperature away from moisture and heat.

See also: Trimethoprim dosage (in more detail)

What happens if I miss a dose?

Take the missed dose as soon as you remember. If it is almost time for your next dose, wait until then to take the medicine and skip the missed dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention if you think you have used too much of this medicine.

Overdose symptoms may include nausea, vomiting, dizziness, headache, confusion, weakness, or flu symptoms.

What should I avoid while taking trimethoprim?

Avoid exposure to sunlight or artificial UV rays (sunlamps or tanning beds). Trimethoprim can make your skin more sensitive to sunlight and sunburn may result. Use a sunscreen (minimum SPF 15) and wear protective clothing if you must be out in the sun.

Trimethoprim side effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Call your doctor at once if you have a serious side effect such as:

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  pale skin, easy bruising or bleeding;

  
  


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  fever, chills, sore throat, flu symptoms; or

  
  


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  severe blistering, peeling, and red skin rash.

  
  

Less serious side effects may include:

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  nausea, vomiting;

  
  


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  sore or swollen tongue; or

  
  


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  mild itching or skin rash.

  
  

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect. You may report side effects to FDA at 1-800-FDA-1088.

Trimethoprim Dosing Information

Usual Adult Dose for Cystitis:

100 mg orally every 12 hours or 200 mg orally every 24 hours for 10 days.

Usual Adult Dose for Cystitis Prophylaxis:

100 mg orally at bedtime for 6 weeks to 6 months.

Usual Adult Dose for Pneumocystis Pneumonia:

15 to 20 mg/kg/day in divided doses every 6 hours (in addition to dapsone 100 mg daily). Therapy should be continued for approximately 14 days in non-HIV patients and 21 days in HIV patients.

Trimethoprim has been used with sulfamethoxazole or dapsone for the treatment of Pneumocystis jiroveci (P carinii) pneumonia.

Usual Pediatric Dose for Cystitis:

2 months to 12 years: 2 to 3 mg/kg every 12 hours for 10 days. The efficacy of trimethoprim as a single agent has not been established in children under 12 years.

12 to 18 years: 100 mg orally every 12 hours or 200 mg orally every 24 hours for 10 days.

Usual Pediatric Dose for Otitis Media:

>=6 months: 5 mg/kg every 12 hours for 10 days (investigational).

What other drugs will affect trimethoprim?

Tell your doctor about all other medications you use, especially phenytoin (Dilantin).

This list is not complete and there may be other drugs that can interact with trimethoprim. Tell your doctor about all your prescription and over-the-counter medications, vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start a new medication without telling your doctor.

More trimethoprim resources

• Trimethoprim Side Effects (in more detail)
• Trimethoprim Dosage
• Trimethoprim Use in Pregnancy & Breastfeeding
• Drug Images
• Trimethoprim Drug Interactions
• Trimethoprim Support Group
• 0 Reviews for Trimethoprim - Add your own review/rating

• trimethoprim Advanced Consumer (Micromedex) - Includes Dosage Information


• Trimethoprim Prescribing Information (FDA)


• Trimethoprim MedFacts Consumer Leaflet (Wolters Kluwer)


• Trimethoprim Monograph (AHFS DI)


• Primsol Solution MedFacts Consumer Leaflet (Wolters Kluwer)


• Proloprim Prescribing Information (FDA)

Compare trimethoprim with other medications

• Bladder Infection
• Otitis Media
• Pneumocystis Pneumonia
• Prevention of Bladder infection

Where can I get more information?

• Your pharmacist can provide more information about trimethoprim.

See also: trimethoprim side effects (in more detail)