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Trimethoprim Dosage

Medically reviewed by Drugs.com. Last updated on March 26, 2019.

Applies to the following strengths: 100 mg; 200 mg; 50 mg/5 mL

Usual Adult Dose for Urinary Tract Infection

100 mg orally every 12 hours or 200 mg orally every 24 hours
Duration of therapy: 10 days

Use: For the treatment of initial episodes of uncomplicated urinary tract infections due to susceptible strains of Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae, Enterobacter species, and coagulase-negative Staphylococcus species (including Staphylococcus saprophyticus)

Usual Pediatric Dose for Urinary Tract Infection

12 years or older: 100 mg orally every 12 hours or 200 mg orally every 24 hours
Duration of therapy: 10 days

Use: For the treatment of initial episodes of uncomplicated urinary tract infections due to susceptible strains of E coli, P mirabilis, K pneumoniae, Enterobacter species, and coagulase-negative Staphylococcus species (including S saprophyticus)

Usual Pediatric Dose for Otitis Media

6 months or older: 5 mg/kg orally every 12 hours for 10 days
Maximum dose: 200 mg/dose

Comments:
-This drug is not indicated for prophylactic or prolonged use in otitis media at any age.
-When infection with Moraxella catarrhalis suspected, use of alternative antimicrobial agents should be considered.

Use: For the treatment of acute otitis media due to susceptible strains of Streptococcus pneumoniae and Haemophilus influenzae

Renal Dose Adjustments

CrCl 15 to 30 mL/min:
-Oral solution: Usual dose should be reduced by 50%.
-Tablets: 50 mg orally every 12 hours
CrCl less than 15 mL/min: Not recommended.

Liver Dose Adjustments

Caution recommended.

Precautions

CONTRAINDICATIONS:
-Hypersensitivity to the active component or any of the ingredients
-Documented megaloblastic anemia due to folate deficiency

Safety and efficacy have not been established in patients younger than 2 months.
-Oral solution: Efficacy in the treatment of acute otitis media has not been established in patients younger than 6 months.
-Tablets: Efficacy of this drug as a single agent has not been established in patients younger than 12 years.

Consult WARNINGS section for additional precautions.

Dialysis

Data not available

Comments:
-Peritoneal dialysis is not effective and hemodialysis is only moderately effective in eliminating this drug.

Other Comments

Storage requirements:
-Oral solution: Store between 15C to 25C (59F to 77F); protect from light.
-Tablets: Store at 20C to 25C (68F to 77F).

General:
-To reduce the development of drug-resistant organisms and maintain effective therapy, this drug should be used only to treat or prevent infections proven or strongly suspected to be caused by susceptible bacteria.
-Culture and susceptibility information should be considered when selecting/modifying antibacterial therapy or, if no data are available, local epidemiology and susceptibility patterns may be considered when selecting empiric therapy.
-Cultures and susceptibility tests should be performed to determine susceptibility to this drug; therapy may be started before test results are known.

Monitoring:
-Hematologic: Complete blood counts (if any clinical signs of blood disorders)
-Metabolic: Potassium levels in elderly patients
-Renal: Renal function (by calculating CrCl) in elderly patients

Patient advice:
-Avoid missing doses and complete the entire course of therapy.
-Consult physician at once if watery and bloody stools (with or without stomach cramps and fever) develop.

Frequently asked questions

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.