Trimethoprim (free base)

    WARNING: This product is for research use only, not for human or veterinary use.

MedKoo CAT#: 318953

CAS#: 738-70-5 (free base)

Description: Trimethoprim (free base) (TMP) is an antibiotic used mainly in the treatment of bladder infections. Other uses include for middle ear infections and travelers' diarrhea. With sulfamethoxazole or dapsone it may be used for Pneumocystis pneumonia in people with HIV/AIDS. It is taken by mouth. Trimethoprim was first used in 1962.

Chemical Structure

Trimethoprim (free base)
CAS# 738-70-5 (free base)

Theoretical Analysis

MedKoo Cat#: 318953
Name: Trimethoprim (free base)
CAS#: 738-70-5 (free base)
Chemical Formula: C14H18N4O3
Exact Mass: 290.13789
Molecular Weight: 290.323
Elemental Analysis: C, 57.92; H, 6.25; N, 19.30; O, 16.53

Price and Availability

Size Price Availability Quantity
1.0g USD 150.0 2 Weeks
2.0g USD 250.0 2 Weeks
5.0g USD 450.0 2 Weeks
10.0g USD 650.0 2 Weeks
20.0g USD 850.0 2 Weeks
50.0g USD 1450.0 2 Weeks
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Related CAS #: 738-70-5 (free base)   56585-33-2 (salt)  

Synonym: Proloprim; Trimethoprim (free base); Trimpex.

IUPAC/Chemical Name: 5-(3,4,5-Trimethoxybenzyl)pyrimidine-2,4-diamine


InChi Code: InChI=1S/C14H18N4O3/c1-19-10-5-8(6-11(20-2)12(10)21-3)4-9-7-17-14(16)18-13(9)15/h5-7H,4H2,1-3H3,(H4,15,16,17,18)


Appearance: Solid powder

Purity: >98% (or refer to the Certificate of Analysis)

Shipping Condition: Shipped under ambient temperature as non-hazardous chemical. This product is stable enough for a few weeks during ordinary shipping and time spent in Customs.

Storage Condition: Dry, dark and at 0 - 4 C for short term (days to weeks) or -20 C for long term (months to years).

Solubility: Soluble in DMSO, not in water

Shelf Life: >2 years if stored properly

Drug Formulation: This drug may be formulated in DMSO

Stock Solution Storage: 0 - 4 C for short term (days to weeks), or -20 C for long term (months).

HS Tariff Code: 2934.99.9001

Preparing Stock Solutions

The following data is based on the product molecular weight 290.323 Batch specific molecular weights may vary from batch to batch due to the degree of hydration, which will affect the solvent volumes required to prepare stock solutions.

Recalculate based on batch purity %
Concentration / Solvent Volume / Mass 1 mg 5 mg 10 mg
1 mM 1.15 mL 5.76 mL 11.51 mL
5 mM 0.23 mL 1.15 mL 2.3 mL
10 mM 0.12 mL 0.58 mL 1.15 mL
50 mM 0.02 mL 0.12 mL 0.23 mL

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1: Falagas ME, Vardakas KZ, Roussos NS. Trimethoprim/sulfamethoxazole for Acinetobacter spp.: A review of current microbiological and clinical evidence. Int J Antimicrob Agents. 2015 Sep;46(3):231-41. doi: 10.1016/j.ijantimicag.2015.04.002. Epub 2015 May 15. Review. PubMed PMID: 26070662.

2: Bruner KE, Coop CA, White KM. Trimethoprim-sulfamethoxazole-induced aseptic meningitis-not just another sulfa allergy. Ann Allergy Asthma Immunol. 2014 Nov;113(5):520-6. doi: 10.1016/j.anai.2014.08.006. Epub 2014 Sep 17. Review. PubMed PMID: 25240332.

3: Tu GW, Ju MJ, Xu M, Rong RM, He YZ, Xue ZG, Zhu TY, Luo Z. Combination of caspofungin and low-dose trimethoprim/sulfamethoxazole for the treatment of severe Pneumocystis jirovecii pneumonia in renal transplant recipients. Nephrology (Carlton). 2013 Nov;18(11):736-42. doi: 10.1111/nep.12133. Review. PubMed PMID: 24571744.

4: Hale SF, Lesar TS. Interaction of vitamin K antagonists and trimethoprim-sulfamethoxazole: ignore at your patient's risk. Drug Metabol Drug Interact. 2014;29(1):53-60. doi: 10.1515/dmdi-2013-0049. Review. PubMed PMID: 24231121.

5: Hsiao HH, Chu NS, Tsai YF, Chang CS, Lin SF, Liu TC. Trimethoprim/sulfamethoxazole-related acute psychosis in the second course of treatment after a stem cell transplant: case report and literature review. Exp Clin Transplant. 2013 Oct;11(5):467-8. Review. PubMed PMID: 24128138.

6: Cunha BA. Minocycline, often forgotten but preferred to trimethoprim-sulfamethoxazole or doxycycline for the treatment of community-acquired meticillin-resistant Staphylococcus aureus skin and soft-tissue infections. Int J Antimicrob Agents. 2013 Dec;42(6):497-9. doi: 10.1016/j.ijantimicag.2013.08.006. Epub 2013 Sep 13. Review. PubMed PMID: 24126085.

7: Capasso C, Supuran CT. Sulfa and trimethoprim-like drugs - antimetabolites acting as carbonic anhydrase, dihydropteroate synthase and dihydrofolate reductase inhibitors. J Enzyme Inhib Med Chem. 2014 Jun;29(3):379-87. doi: 10.3109/14756366.2013.787422. Epub 2013 Apr 29. Review. PubMed PMID: 23627736.

8: Di Carlo P, D'Alessandro N, Guadagnino G, Bonura C, Mammina C, Lunetta M, Novo S, Giarratano A. High dose of trimethoprim-sulfamethoxazole and daptomycin as a therapeutic option for MRSA endocarditis with large vegetation complicated by embolic stroke: a case report and literature review. Infez Med. 2013 Mar;21(1):45-9. Review. PubMed PMID: 23524901.

9: Al-Quteimat OM, Al-Badaineh MA. Methotrexate and trimethoprim-sulphamethoxazole: extremely serious and life-threatening combination. J Clin Pharm Ther. 2013 Jun;38(3):203-5. doi: 10.1111/jcpt.12060. Epub 2013 Mar 22. Review. PubMed PMID: 23521709.

10: Bodro M, Paterson DL. Has the time come for routine trimethoprim-sulfamethoxazole prophylaxis in patients taking biologic therapies? Clin Infect Dis. 2013 Jun;56(11):1621-8. doi: 10.1093/cid/cit071. Epub 2013 Feb 7. Review. PubMed PMID: 23392396.

11: Ho JM, Juurlink DN. Considerations when prescribing trimethoprim-sulfamethoxazole. CMAJ. 2011 Nov 8;183(16):1851-8. doi: 10.1503/cmaj.111152. Epub 2011 Oct 11. Review. PubMed PMID: 21989472; PubMed Central PMCID: PMC3216436.

12: Delanaye P, Mariat C, Cavalier E, Maillard N, Krzesinski JM, White CA. Trimethoprim, creatinine and creatinine-based equations. Nephron Clin Pract. 2011;119(3):c187-93; discussion c193-4. doi: 10.1159/000328911. Epub 2011 Aug 11. Review. PubMed PMID: 21832843.

13: Vouloumanou EK, Karageorgopoulos DE, Rafailidis PI, Michalopoulos A, Falagas ME. Trimethoprim/sulfametrole: evaluation of the available clinical and pharmacokinetic/pharmacodynamic evidence. Int J Antimicrob Agents. 2011 Sep;38(3):197-216. doi: 10.1016/j.ijantimicag.2011.04.016. Epub 2011 Jul 13. Review. PubMed PMID: 21741802.

14: Sibanda EL, Weller IV, Hakim JG, Cowan FM. Does trimethoprim-sulfamethoxazole prophylaxis for HIV induce bacterial resistance to other antibiotic classes? Results of a systematic review. Clin Infect Dis. 2011 May;52(9):1184-94. doi: 10.1093/cid/cir067. Review. PubMed PMID: 21467024; PubMed Central PMCID: PMC3070868.

15: Pappas G, Athanasoulia AP, Matthaiou DK, Falagas ME. Trimethoprim-sulfamethoxazole for methicillin-resistant Staphylococcus aureus: a forgotten alternative? J Chemother. 2009 Apr;21(2):115-26. Review. PubMed PMID: 19423463.

16: Korbila IP, Manta KG, Siempos II, Dimopoulos G, Falagas ME. Penicillins vs trimethoprim-based regimens for acute bacterial exacerbations of chronic bronchitis: meta-analysis of randomized controlled trials. Can Fam Physician. 2009 Jan;55(1):60-7. Review. PubMed PMID: 19155372; PubMed Central PMCID: PMC2628840.

17: Faria LC, Resende CC, Couto CA, Couto OF, Fonseca LP, Ferrari TC. Severe and prolonged cholestasis caused by trimethoprim-sulfamethoxazole: a case report. Clinics (Sao Paulo). 2009;64(1):71-4. Review. PubMed PMID: 19142556; PubMed Central PMCID: PMC2671966.

18: Wisell KT, Kahlmeter G, Giske CG. Trimethoprim and enterococci in urinary tract infections: new perspectives on an old issue. J Antimicrob Chemother. 2008 Jul;62(1):35-40. doi: 10.1093/jac/dkn147. Epub 2008 Apr 12. Review. PubMed PMID: 18408238.

19: Sud B, Salvaggio M, Greenfield R, Bronze MS. Part XI. Trimethoprim-sulfamethoxazole, nitrofurantoin, chloramphenicol, metronidazole and tinidazole, rifaximin, and nitazoxanide. J Okla State Med Assoc. 2007 Jul;100(7):267-72. Review. Erratum in: J Okla State Med Assoc. 2007 Oct;100(10):405. Greenfield, Ronald A [corrected to Greenfield, Ronald]. PubMed PMID: 17896614.

20: Bhambri S, Del Rosso JQ, Desai A. Oral trimethoprim/sulfamethoxazole in the treatment of acne vulgaris. Cutis. 2007 Jun;79(6):430-4. Review. PubMed PMID: 17713145.