Is this medication very expensive?

 No   Yes 

• Dosage of Trimethoprim in details
• Trimethoprim interactions
• Trimethoprim reviews

Dosage of Trimethoprim in details

Trimethoprim Dosage

Applies to the following strength(s): 100 mg; 200 mg; 50 mg/5 mL

The information at Drugs.com is not a substitute for medical advice. Always consult your doctor or pharmacist.

Usual Adult Dose for:

• Urinary Tract Infection
• Cystitis Prophylaxis
• Pneumocystis Pneumonia

Usual Pediatric Dose for:

• Otitis Media
• Urinary Tract Infection
• Pneumocystis Pneumonia

Additional dosage information:

• Renal Dose Adjustments
• Liver Dose Adjustments
• Precautions
• Dialysis
• Other Comments

Usual Adult Dose for Urinary Tract Infection

Acute uncomplicated infections: 100 mg orally every 12 hours or 200 mg orally every 24 hours for 10 days

Usual Adult Dose for Cystitis Prophylaxis

(Not approved by FDA)

100 mg orally at bedtime for 6 weeks to 6 months

Usual Adult Dose for Pneumocystis Pneumonia

(Not approved by FDA)

Centers for Disease Control and Prevention (CDC) recommendations:

HIV-infected patients: 15 mg/kg/day orally in 3 divided doses (in addition to dapsone 100 mg daily) for 21 days

Trimethoprim with dapsone is recommended as alternative treatment of mild-to-moderate Pneumocystis jirovecii pneumonia.

Usual Pediatric Dose for Otitis Media

Acute infections:

6 months or older: 5 mg/kg orally every 12 hours for 10 days

Usual Pediatric Dose for Urinary Tract Infection

Acute uncomplicated infections:

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

(Not approved by FDA)

2 months to less than 12 years: 2 to 3 mg/kg orally every 12 hours for 10 days

Usual Pediatric Dose for Pneumocystis Pneumonia

(Not approved by FDA)

CDC recommendations:

HIV-infected adolescents: 15 mg/kg/day orally in 3 divided doses (in addition to dapsone 100 mg daily) for 21 days

Trimethoprim with dapsone is recommended as alternative treatment of mild-to-moderate Pneumocystis jirovecii pneumonia.

Renal Dose Adjustments

CrCl 15 to 30 mL/min: Usual dose should be reduced by 50%.

CrCl less than 15 mL/min: Not recommended.

Liver Dose Adjustments

Caution is recommended in patients with hepatic impairment.

Precautions

Trimethoprim is contraindicated in patients with documented megaloblastic anemia due to folate deficiency.

High doses and/or prolonged use of Trimethoprim may cause bone marrow depression manifested as thrombocytopenia, leukopenia, and/or megaloblastic anemia.

Trimethoprim should be discontinued in patients if early symptoms of blood dyscrasias develop (sore throat, fever, pallor, or purpura) and if significant abnormalities in blood counts are found.

Monitoring of potassium concentrations is recommended, especially in elderly patients.

Safety and effectiveness have not been established in pediatric patients less than 2 months of age. Effectiveness in the treatment of acute otitis media has not been established in pediatric patients less than 6 months of age. The efficacy of Trimethoprim as a single agent in the treatment of urinary tract infection has not been established in pediatric patients less than 12 years of age.

Dialysis

CrCl less than 15 mL/min: Not recommended.

Peritoneal dialysis is not effective and hemodialysis only moderately effective in eliminating Trimethoprim.

Other Comments

Trimethoprim can interfere with serum methotrexate assays by the Competitive Binding Protein Technique (CBPA) when a bacterial dihydrofolate reductase is used as the binding protein. There is no interference with methotrexate radioimmunoassays (RIA). Trimethoprim may also interfere with creatinine assays using the Jaffe alkaline picrate reaction, resulting in 10% overestimations of the range of normal values.

More about Trimethoprim

• Side Effects
• During Pregnancy or Breastfeeding
• Dosage Information
• Drug Images
• Drug Interactions
• Support Group
• En Espanol
• 10 Reviews - Add your own review/rating

Consumer resources

• Trimethoprim
• Trimethoprim solution
• Trimethoprim (Advanced Reading)

• Other brands: Trimpex, Trimethoprim, Proloprim

Professional resources

• Trimethoprim (AHFS Monograph)
• More (2) »

Related treatment guides

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

What other drugs will affect Trimethoprim?

Tell your doctor about all medications you use, and those you start or stop using during your treatment with Trimethoprim, especially:

• a diuretic (water pill);

• dofetilide (Tikosyn);

• heart or blood pressure medication such as procainamide (Procan, Pronestyl) and others;

• leucovorin (folinic acid);

• methotrexate (Rheumatrex, Trexall); or

• phenytoin (Dilantin).

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

Trimethoprim interactions

Trimethoprim may inhibit the hepatic metabolism of phenytoin. Trimethoprim (Trimethoprim (Trimethoprim tablet) tablet), given at a common clinical dosage, increased the phenytoin half-life by 51% and decreased the phenytoin metabolic clearance rate by 30%. When administering these drugs concurrently, one should be alert for possible excessive phenytoin effect.

Drug/Laboratory Test Interactions

Trimethoprim (Trimethoprim (Trimethoprim tablet) tablet) can interfere with a serum methotrexate assay as determined by the Competitive Binding Protein Technique (CBPA) when a bacterial dihydrofolate reductase is used as the binding protein. No interference occurs, however, if methotrexate is measured by a radioimmunoassay (RIA). The presence of Trimethoprim (Trimethoprim (Trimethoprim tablet) tablet) may also interfere with the Jaffé alkaline picrate reaction assay for creatinine resulting in over estimations of about 10% in the range of normal values.

References

1. DailyMed. "POLYMYXIN B SULFATE; TRIMETHOPRIM SULFATE: DailyMed provides trustworthy information about marketed drugs in the United States. DailyMed is the official provider of FDA label information (package inserts).". https://dailymed.nlm.nih.gov/dailyme... (accessed September 17, 2018).
2. FDA/SPL Indexing Data. "AN164J8Y0X: The UNique Ingredient Identifier (UNII) is an alphanumeric substance identifier from the joint FDA/USP Substance Registration System (SRS).". https://www.fda.gov/ForIndustry/Data... (accessed September 17, 2018).
3. MeSH. "Folic Acid Antagonists". https://www.ncbi.nlm.nih.gov/mesh/68... (accessed September 17, 2018).

Reviews

User reports

Consumer reviews

Information checked by Dr. Sachin Kumar, MD Pharmacology