* Adapted from Sunnybrook Hospital

Trimethoprim (TMP)Sulfamethoxazole (SMX)
Suspension 8 mg/ml 40 mg/ml
Injectable 16 mg/ml 80 mg/ml
SS (single strength) tablet 80 mg 400 mg
DS (double strength) tablet 160 mg 800 mg

* 2 SS tabs = 1 DS tab= 20 mL oral suspension = 10mL IV

Trimethoprim/sulfamethoxazole is dosed by trimethoprim (TMP) component.

Common doses of oral TMP/SMX:

RegimenTotal mg of TMP / day
1 SS BID 160 mg
1 DS BID 320 mg
1 DS TID 480 mg
1 DS QID 640 mg
2 DS BID 640 mg
2 DS TID 960 mg
2 DS QID 1280 mg
3 DS TID 1440 mg

If Intravenous Cotrimoxazole is Required

10 mg/kg TMP per Day
Weight (kg)IV DoseTotal TMP Dose (mg/day)
40-49 10 mL Q8H 480
50-64 10 mL Q6H 640
65-74 15 mL Q8H 720
75-99 15 mL Q6H 960
100-129 20 mL Q6H 1280
15 mg/kg TMP per Day
Weight (kg)IV DoseTotal TMP Dose (mg/day)
40-44 10 mL Q6H 640
45-49 15 mL Q8H 720
50-69 15 mL Q6H 960
70-79 25 mL Q8H 1200
80-89 20 mL Q6H 1280
90-99 30 mL Q8H 1440
100-109 25 mL Q6H 1600
110-119 35 mL Q8H 1680
120-129 30 mL Q6H 1920
20 mg/kg TMP per Day
Weight (kg) IV Dose Total TMP Dose (mg/day)
40-54 15 mL Q6H 960
55-69 20 mL Q6H 1280
70-79 30 mL Q8H 1440
80-89 25 mL Q6H 1600
90-104 30 mL Q6H 1920
105-119 35 mL Q6H 2240
120-134 40 mL Q6H 2560
Creatinine ClearanceSuggested Dosing Guidelines
> 30mL/min Bacterial infections: 8-12mg/kg/day of TMP in 2 – 4 divided doses

PJP: 15-20mg/kg/day of TMP in 2 – 4 divided doses
10 – 30 mL/min Bacterial infections: 75% of usual dose (6 – 9 mg/kg/day of TMP in 2 – 4 divided doses)

PJP: 12-15mg/kg/day of TMP in 2 – 4 divided doses
< 10 mL/min (including PD) Generally not recommended If required: use 50% of usual doses Bacterial infections: 5mg/kg/day in 2 – 4 divided doses

PJP: 7.5-10mg/kg/day of TMP in 2-4 divided doses
Hemodialysis 50% of usual dose – schedule doses post-dialysis
Continuous Renal Replacement Therapy (CRRT) Bacterial infections: 7.5mg/kg/day of TMP in 2-4 divided doses PJP/ Stenotrophomonas: 15mg/kg/day of TMP in 2- 4 divided doses