From the Guidelines
The appropriate dosage of Bactrim (trimethoprim-sulfamethoxazole) for a 9-year-old patient is typically 8-12 mg/kg/day of the trimethoprim component, divided into two doses, as recommended by the most recent and highest quality study 1.
Dosage Calculation
To calculate the dosage, the trimethoprim component is used, with a typical dose range of 8-12 mg/kg/day. For a 9-year-old patient, this would translate to:
- 8 mg/kg/day of trimethoprim, which is equivalent to 40 mg/kg/day of sulfamethoxazole, divided every 12 hours for 10-14 days for a standard urinary tract infection.
Important Considerations
- The medication should be given with plenty of fluids to prevent crystalluria.
- Dosing should be adjusted if the child has kidney impairment.
- Common side effects include rash, gastrointestinal upset, and photosensitivity, so sun protection is advised.
- Parents should be instructed to complete the full course of antibiotics even if symptoms improve.
Mechanism of Action
This medication works by inhibiting two steps in bacterial folate synthesis, creating a synergistic antibacterial effect that is effective against many common pathogens.
Monitoring for Adverse Effects
If the child develops severe rash, difficulty breathing, or persistent fever while taking Bactrim, medical attention should be sought immediately, as indicated in various studies, including 1 and 1.
From the FDA Drug Label
Pediatric Use: Sulfamethoxazole and trimethoprim is not recommended for infants younger than 2 months of age (see INDICATIONS and CONTRAINDICATIONS sections).
The FDA drug label does not provide specific dosage and usage guidelines for a 9-year-old patient taking Bactrim (trimethoprim-sulfamethoxazole).
From the Research
Dosage and Usage of Bactrim for a 9-year-old Patient
- The appropriate dosage and usage of Bactrim (trimethoprim-sulfamethoxazole) for a 9-year-old patient are not explicitly stated in the provided studies.
- However, according to 2, Bactrim is used as an alternative to ampicillin and amoxicillin in children with otitis media, and is preferred when these patients are penicillin-sensitive or when the infection is caused by beta-lactamase-producing Haemophilus influenzae.
- A study published in 3 compared the effectiveness of twice-daily trimethoprim-sulfamethoxazole versus amoxicillin-clavulanate in the treatment of acute otitis media in children, and found that trimethoprim-sulfamethoxazole was more effective clinically and produced fewer side effects.
- The dosage of trimethoprim-sulfamethoxazole should be adjusted when the creatinine clearance is less than 30 ml/min, as stated in 4.
- Bactrim is active in vitro against various gram-positive and gram-negative bacteria, and is useful for prophylaxis and treatment of selected infections of the genitourinary, respiratory, and gastrointestinal tracts, as mentioned in 4 and 5.
Potential Side Effects and Interactions
- Common adverse reactions to trimethoprim-sulfamethoxazole include gastrointestinal intolerance and skin eruptions, as stated in 2.
- Hematologic reactions, such as anemia, thrombocytopenia, granulocytopenia, and agranulocytosis, can occur rarely, as mentioned in 2.
- The incidence of untoward reactions to trimethoprim-sulfamethoxazole compares favorably with that of standard agents administered for the same indications, as stated in 2.