Prophylaxis for Pneumocystis Carinii Pneumonia (PCP) with Trimethoprim Sulfamethoxazole (TMP-SMX)

 

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)

 

Prophylaxis in adults may include one of the following:

(1) 1 double strength tablet daily

(2) 1 single strength tablet daily

(3) 1 double strength tablet daily for 3 consecutive days per week

 

Prophylaxis in children:

(1) daily dose based on body surface area (BSA) 150 mg TMP per square meter BSA and 750 mg SMX per square meter BSA

(2) maximum daily dose is 320 mg TMP and 1600 mg SMX

(3) daily dose divided in 2 and given orally every 12 hours

(4) therapy is given on 3 consecutive days per week

Body Surface Area	Tablet every 12 hours
< 0.53 square meter	use liquid suspension
0.53 square meter	0.5 single strength
1.06 square meter	1.0 single strength
1.59 square meters	1.5 single strength
2.12 square meter	2.0 single strength or 1 double strength

 

Side effects are relatively common in patients receiving prophylaxis. Lower dose or 3 day per week regimens have a lower risk of complications.

 

TMP-SMX is contraindicated in infants < 2 months old.

 

If renal function is impaired, then the dose should be reduced.

 

Creatinine Clearance	Dosing Adjustment
> 30 mL per min	normal
15 - 30 mL per min	reduce by 50%
< 15 mL per min	use alternative therapy