Antimicrobials
Trimethoprim

Trimethoprim

N/A
N/A
See below under General Info

General Information

Hospital Formulary Status Yes (PO solid)

In-Hospital Cost will be updated

PharmaCare Formulary Status Yes (PO solid)

Special Authority None

PharmaCare Coverage 100mg PO - $0.3059/tab 200mg PO - $0.6286/tab

Outpatient Cost 100mg PO - $0.33-0.42/tab 200mg PO - $0.60-0.75/tab

Generally, well tolerated in patients without HIV (ADR rate: 6-8%) In patients with HIV, ADRs are common and severe (ADR rate: 25-50%)

Gastritis (PO and IV)

  •  sx: nausea, vomiting, and diarrhea
  •  common

Skin toxicity (PO and IV)

  •  common sx: rash (3-7% with doses of 200mg/day) and pruritus
  •  uncommon sx: mucosal membrane ulceration, erythema, scaling and skin detachment
  •  may involve SJS, exfoliative dermatitis and toxic epidermal necrolysis

Nephrotoxicity (mainly with IV)

  •  uncommon
  •  TMP decreases tubular secretion of creatinine, leading to increase in SCr that is not reflective of a true GFR reduction
  •  may include renal tubular acidosis
  •  usually reversible
  •  some patients may experience prolonged recovery after discontinuation

Hyperkalemia (mainly with IV)

  •  caused by blockade of collecting tubule sodium channel by TMP
  •  more common in patients with HIV treated with high doses
  •  modest elevation in plasma potassium concentration can occur in patients without HIV with normal doses
  •  increased 7-day risk of sudden death in older patients receiving TMP-SMX and spironolactone, ACE inhibitor or ARB

Folate deficiency (mainly with IV)

  •  use with caution in patients with folate deficiency or at risk for complications of folate deficiency (pregnancy, chronic hemolytic anemia)
  •  TMP weakly inhibits human dihydrofolate reductase and reduces folate available for hematopoiesis
  •  may cause megaloblastic changes (macrocytic anemia, mild thrombocytopenia, leukopenia) when given over long periods or in high doses
  •  treatment: folic acid supplementation (except in patients with AIDS and Pneumocystis pneumonia)

Other

  •  hyponatremia
  •  hemolysis in patients with glucose-6-phosphate dehydrogenase deficiency
  •  neutropenia