Trimethoprim-sulfamethoxazole (TMP-SMX, Bactrim, Septra) can be used as treat a patient with Pneumocystis carinii pneumonia (PCP).
Oral formulations for TMP-SMX (in fixed dose ratio of 1 to 5):
(1) single strength tablet (80 mg TMP, 400 mg SMX)
(2) double strength tablet (DS, 160 mg TMP, 800 mg SMX)
(3) suspension (8 mg TMP per mL, 40 mg SMX per mL)
TMP-SMX is contraindicated in infants < 2 months old.
Dosage range for treatment of Pneumocystis carinii pneumonia per day:
(1) low end of dosing range: 15 mg/kg TMP and 75 mg/kg SMX
(2) high end of dosing range: 20 mg/kg TMP and 100 mg/kg SMX
The daily dose is divided for q6h po administration. To simplify the calculations, this equations to q6h doses of:
(1) low end of dosing range: 4 mg/kg TMP and 20 mg/kg SMX
(2) high end of dosing range: 5 mg/kg TMP and 25 mg/kg SMX
Duration of therapy is for 14 to 21 days (2 -3 weeks).
If tablets are given the following table can be used for the high end of the dosage range:
Body Weight in Kg
Single Strength Tablet po q6h
Double Strength Tablet po q6h
If renal function is impaired, then the dose should be reduced.
> 30 mL per min
15 - 30 mL per min
reduce by 50%
< 15 mL per min
use alternative therapy
For the creatinine clearance of 15 - 30 mL this works out to the following at the high end of the dosing range:
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Specialty: Infectious Diseases, Pharmacology, clinical