Trimethoprim is a Medicine belongs to Antibacterials group whose information about Brand can be referenced from   Book : Martindale    Page : 387   Edition : 37  

  ►   Brandname : Infectotrimet, Motrim, Solotrim, Trimopan, Primsol, Proloprim, Trimpex
  ►  Strength : Tablet with 100 mg.  Tablet with 200 mg.  with

Reference of this Medicine for its Strength can be taken from   Book : Basic & Clinical pharmacology    Page : 837   Edition : 12   Martindale    Page : 387   Edition : 37  
A Route of administration in pharmacology and toxicology is the path by which a drug, fluid, poison, or other substance is taken into the body. Routes of administration are generally classified by the location at which the substance is applied. Common examples include oral and intravenous administration.

  ►  Route of administration : Oral, IV infusion
Reference :-   Book : Martindale    Page : 387   Edition : 37  

Dosing of Medicine differ in Adult & Pediatrics ↓

Adult Dose

S.No Ailment   Route   Dose Min   Dose Max   Unit   Dosage Form   Frequency   Additional Info
1 Acute infection Oral 100 200 mg Tablet b.d. Doses of 200 or 300 mg daily as a single dose are also used
2 Pneumocystis pneumonia Oral 20 mg/kg Given with dapsone
3 Long-term prophylaxis Oral 100 mg Given at night.
4 IV injection or infusion 200 mg Injection The usual dose has been 200 mg every 12 hours; initial doses may be higher or given more frequently in severely ill patients.

Ref :-  Book : Martindale    Page : 387   Edition : 37  



Pediatric Dose

S.No Ailment   Age Min   Age Max   Weight ( Kg ) Route   Dose Min   Dose Max   Unit   Dosage Form   Frequency  Additional Info  
1 Treatment of urinary-or respiratory-tract infections 3 mg/kg
2 Treatment of urinary-or respiratory-tract infections 1 Month 4 mg/kg
3 Treatment of urinary-or respiratory-tract infections 6 Week 6 Month 25 mg b.d.
4 Treatment of urinary-or respiratory-tract infections 6 Month 6 Year 50 mg b.d.
5 Treatment of urinary-or respiratory-tract infections 6 Year 100 mg b.d.
6 Prophylaxis 2 mg/kg

Ref :- Book : Martindale    Page : 387   Edition : 37  
►  Side Effect : Mild gastrointestinal disturbances, Nausea, Vomiting, Glossitis, Rises in serum creatinine and blood-urea nitrogen, Photosensitivity, Hypersensitivity reactions, Angioedema, Aseptic meningitis, Depression of haematopoiesis, Megaloblastic anaemia, Thrombocytopenia, Leukopenia, Methaemoglobinaemia
Ref :-   Book : Martindale    Page : 386   Edition : 37.  

►  Drug Interaction : Drug interaction of Trimethoprim is with , Diuretics, Angiotensin conveting enzyme inhibitors ,  Phenytoin , Digoxin , Procainamide , Rosiglitazone , Repaglinide , Warfarin , Zidovudine, Zalcitabine, Lamivudine, Dapsone , Pyrimethamine , Methotrexate
Ref :-   Book : Martindale    Page : 386   Edition : 37.  


  ►    Mechanism of Drug Drug Interaction :  Trimethoprim may increase serum concentrations and potentiate the effect of some drugs, including phenytoin, digoxin, procainamide, rosiglitazone, and repaglinide. The effect may be due to competitive inhibition of renal excretion, decreased metabolism, or both. It has been suggested that trimethoprim may potentiate the effects of warfarin. Trimethoprim has been reported to reduce the renal excretion and increase blood concentrations of zidovudine, zalcitabine, and lamivudine. Trimethoprim and dapsone increase each other’s serum concentrations, whereas rifampicin may decrease trimethoprim concentrations. An increased risk of nephrotoxicity has been reported with the use of trimethoprim or co-trimoxazole and ciclosporin. Intravenous use of trimethoprim and sulfonamides may reduce ciclosporin concentrations in blood. Hyponatraemia has been reported in patients given trimethoprim with diuretics. An increased risk of thrombocytopenia has been seen in elderly patients given co-trimoxazole with diuretics, although it is unclear which component of the antibacterial is responsible. Use of trimethoprim with other depressants of bone marrow function may increase the likelihood of myelosuppression, and there may be a particular risk of megaloblastic anaemia if it is given with other folate inhibitors, such as pyrimethamine or methotrexate. Severe hyperkalaemia has been noted in patients given trimethoprim (or co-trimoxazole) together with an ACE inhibitor.
Ref :-   Book : Martindale    Page : 386   Edition : 37.  


►  Contraindication : Hypersensitivity, Renal impairment, It should be used with caution in patients with severe hepatic damage as changes may occur in the absorption and metabolism of trimethoprim, Trimethoprim should not usually be given to patients with serious haematological disorders and particularly not in megaloblastic anaemia secondary to folate depletion. Care should be taken in patients with actual, or possible, folate deficiency and use of folinic acid should be considered. Trimethoprim should be avoided during pregnancy.
Ref :-   Book : Martindale    Page : 386   Edition : 37.  
  ►  Mechanism of Action :   Trimethoprim, a trimethoxybenzylpyrimidine, selectively inhibits bacterial dihydrofolic acid reductase, which converts dihydrofolic acid to tetrahydrofolic acid, a step leading to the synthesis of purines and ultimately to DNA. trimethoprim or pyrimethamine in combination with a sulfonamide blocks sequential steps in folate synthesis, resulting in marked enhancement (synergism) of the activity of both drugs. The combination often is bactericidal, compared with the bacteriostatic activity of a sulfonamide alone.
Ref :-   Book : Basic & Clinical pharmacology    Page : 833   Edition : 12.  

Pathway of DIETARY Product


​   ► Act.Comp / Nutrient / Food / Herb as follows :- Tulsi with Another pathway.  

  ►  Pathway with its reference as follows :-
  • --- (Duke, J. (2002). Hand Book Of Medicinal Herbs (2nd ed.). United States Of America: CRC Press. )

  •   ►  URL --
  • https://www.crcpress.com/Handbook-of-Medicinal-Herbs-Second-Edition/Duke/p/book/9780849312847 .

  • DIETARY Substance Interactions


    ​   ► This Medicine interact with :- NA



    ContraIndication DIETARY Substance


    ​   ► This Medicine contraindicate with :- NA

    ►   Route of Elimination :   Renal, Faecal
    Ref :-   Book : Martindale    Page : 386   Edition : 37.  

    ►    Plasma Half-life :   Min value :-   8 hours,    Max value :-   10 hours.  
    Ref :-   Book : Martindale    Page : 387   Edition : 37.  

    ►    Peak Plasma Concentration :   Min value :-   1 hour,    Max value :-   4 hours.  
    Ref :-   Book : Martindale    Page : 387   Edition : 37.