(IV): 8-10mg/kg/day divided q6-12h. 
PCP: 15-20mg/kg/day in 3 or 4 divided doses.

(Oral): UTI: 1 DS tab (160mg TMP/800mg SMX) po q12h.

Patients who receive cotrimoxazole intravenously or orally and have impaired renal function should be dosed according to the following dosage schedule: 
Creatinine Clearance Dosage  (mL/min) 
Above 30: Standard regimen 
15-30: 1/2 standard regimen 
Below 15: Not recommended 

Non-PCP:
[>30 ml/min]: no change 
[15-30]: 2.5 mg/kg  q12h
[<15 ml/min]: not recommended by manufacturer. 

Alternative (LESS SUPPORT): 2.5mg/kg q24h (Avoid if possible due to risk of crystalluria/ nephrolithiasis)

PCP:
[>30 ml/min]: no change 
[15-30]: 5mg/kg q12h
[<15 ml/min]: not recommended by manufacturer. 

Alternative (LESS SUPPORT): 5mg/kg q24h (Avoid if possible due to risk of crystalluria/ nephrolithiasis)

Hemodialysis:
Not recommended by manufacturer.
Alternative (LESS SUPPORT):
Oral:  Avoid if possible. If unavoidable, give one SS/DS q24h.
IV:  Avoid if possible. If unavoidable, give 5mg/kg q24h.

Guidelines for the administration of cotrimoxazole (based on the trimethoprim component) in patients with renal dysfunctions (Paap & Nahata, 1995; Paap & Nahata, 1989): 
INDICATION/RENAL FUNCTION DOSE 
PCP TREATMENT 
CrCl > than 30 ml/min
  15-20 mg/kg/day divided q6-8h 
CrCl 15 to 30 ml/min 
15-20 mg/kg/day divided q6-8h for 48h then 7-10 mg/kg/day divided q12h 
CrCl < 15 ml/min 
15-20 mg/kg/dose q48h (or 7-10 mg/kg/day divided q12-24h) 
Hemodialysis 
15-20 mg/kg/dose before dialysis and 7-10 mg/kg/dose after dialysis

PCP PROPHYLAXIS 
CrCl > 30 ml/min
5 mg/kg q24h  for 3 to 7 doses/week 
CrCl 15 to 30 ml/min
5 mg/kg q24-48h for 3 to 7 doses/week 
CrCl < 15 ml/min
5 mg/kg q48-72h 
Hemodialysis 
5 mg/kg after dialysis 

OTHER INFECTIONS 
CrCl greater than 30 ml/min
8-12 mg/kg/day divided q12h for 14 days then 4-6 mg/kg q24h 
CrCl 15 to 30 ml/min 
8-12 mg/kg/day divided q12h for 1-2 days then 4-6 mg/kg/day q24h 
CrCl less than 15 ml/min 
8-12 mg/kg/dose q48h (or 4-6 mg/kg/day divided q12-24h) 
Hemodialysis 
8-12 mg/kg/dose before dialysis and 4-6 mg/kg/dose after dialysis