Trimethoprim-sulfamethoxazole

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Revision as of 03:41, 15 August 2019 by Aidan (talk | contribs)

Identification

  • Sulfonamide antibiotic

Brand Names

  • Septra
  • Bactrim (US)
  • TMP-SMX

Dosing

Based on the trimethroprim component.

Form TMP SMX
Suspension 8 mg/ml 40 mg/ml
Injection 16 mg/ml 80 mg/ml
SS tab 80 mg 400 mg
DS tab 160 mg 800 mg

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

Oral Dosing

  • Ranges from 1 SS tab BID (160 mg TMP TDD) to 3 DS tabs TID (1440 mg TMP TDD)

Intravenous Dosing

  • 10 to 20 mg/kg TMP total daily dose, split TID to QID

TMP 10 mg/kg per day

Weight (kg) Dose (IV) Total dose TMP (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

TMP 15 mg/kg per day

Weight (kg) Dose (IV) Total dose TMP (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

TMP 20 mg/kg per day

Weight (kg) Dose (IV) Total dose TMP (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

Renal Dosing

CrCl (mL/min) Bacterial infection (TMP) PJP (TMP)
> 30 8-12 mg/kg/day in 2-4 divided doses 15-20 mg/kg/day in 2-4 divided doses
10 to 29 75% of usual dose 12-15 mg/kg/day in 2-4 divided doses
< 10, including PD Generally not recommended; use 50% of usual dose Generally not recommended; use 7.5-10 mg/kg/day in 2-4 divided doses
Hemodialysis 50% of usual dose, scheduled post-dialysis 50% of usual dose, scheduled post-dialysis
CRRT 7.5 mg/kg/day in 2-4 divided doses 15 mg/kg/day in 2-4 divided doses

Notable Side Effects

  • Allergic reactions, including anaphylaxis and a relatively high rate of SJS/TEN
  • GI upset, including nausea at higher doses
  • Interactions
    • Increases warfarin levels
  • Anemia, neutropenia and thrombocytopenia
    • It is a mild folate antagonist
  • Hepatotoxicity
  • Hyperkalemia
  • Hypoglycemia
  • Acute kidney injury, though it also increases tubular creatinine reabsorption
  • Renal tubular acidosis

Further Reading