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trimethoprim; TMP (Proloprim, Trimpex)

Tradenames: Prolorpin, Trimpex. Indications: - bacterial infections due to susceptible organisms [5] - urinary tract infections - acute otitis media in children - acute exacerbations of chronic bronchitis in adults - Pneumocystis carinii pneumonia (PCP) Dosage: 1) 100 mg PO BID or 200 mg PO QD 2) PCP: 15 mg/kg/day in divided doses given with sulfamethoxazole or dapsone Tabs: 100 & 200 mg. Dosage adjustment in renal failure: creatinine clearance dosage > 50-90 mL/min 12 hour dosing 10-50 mL/min* 18 hour dosing < 10 mL/min# 24 hour dosing, not recommended [4] * same dose for continuous arteriovenous hemofiltration # dose after hemodialysis Moderately dialyzable: 20-50% Pharmacokinetics: 1) rapidly & extensively absorbed 2) time to peake serum concentration 1-4 hours 3) partially metabolized in liver 4) 60-80% excreted unchanged in the urine 5) 1/2life 11 hours (20-49 hours ESRD) Monitor: Therapeutic range: - Peak: 5-15 ug/mL - Trough: 2-8 ug/mL Antimicrobial activity: - Enterobacter [5] - Escherichia coli - Klebsiella - Proteus - Staphylococcus aureus - Haemophilus influenzae - Streptococcus [5] Adverse effects: 1) common (> 10%) 1) rash 2) pruritus 2) less common (1-10%) - megaloblastic anemia 3) uncommon (< 1%) - fever, exfoliative dermatitis, nausea/vomiting, epigastric distress, cholestatic jaundice, thrombocytopenia, neutropenia, leukopenia, increased LFTs, increased serum creatinine* & BUN - hyperkalemia & acute kidney injury [7] * trimethoprim can increase serum creatinine up to 0.5 mg/dL - this increase is not associated with loss of renal function [6] (see test interaction) Drug interactions: - renin-angiotensin-aldosterone system inhibitor in combination further increases risk of hyperkalemia & acute kidney injury [7] Test interactions: - serum creatinine: - trimethoprim inhibits tubular secretion of creatinine - trimethoprim can increase serum creatinine up to 0.5 mg/dL* * this increase is not associated with loss of renal function [6] Mechanism of action: - inhibits synthesis of tetrahydrofolate by inhibiting dihydrofolate reductase, thus inhibiting microbial growth

Interactions

drug interactions

General

folate antagonist; folic acid analog; folic acid antagonist other antibiotic

Properties

MISC-INFO: elimination route KIDNEY pregnancy-category C safety in lactation - protein-binding 42-60% elimination by hemodialysis -

Database Correlations

PUBCHEM cid=5578

References

  1. The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
  2. Kaiser Permanente Northern California Regional Drug Formulary, 1998
  3. Department of Veterans Affairs, VA National Formulary
  4. Geriatric Dosage Handbook, 6th edition, Selma et al eds, Lexi-Comp, Cleveland, 2001
  5. Deprecated Reference
  6. Medical Knowledge Self Assessment Program (MKSAP) 17, American College of Physicians, Philadelphia 2015
  7. Crellin E, Mansfield KE, Leyrat C et al. Trimethoprim use for urinary tract infection and risk of adverse outcomes in older patients: Cohort study. BMJ 2018 Feb 9; 360:k341 PMID: 29438980 Free PMC Article http://www.bmj.com/content/360/bmj.k341

Component-of

phenazopyridine/sulfamethoxazole/trimethoprim polymixin-B/trimethoprim (Polytrim) sulfadiazine/trimethoprim sulfamethazine/trimethoprim trimethoprim/sulfamethoxazole; cotrimoxazole (Bactrim, Septra, Cotrim, Sulfatrim, Sulfoxatrim, Trisulfam, Uroplus)