Sulfamethoxazole and Trimethoprim (Co-trimoxazole) is a Medicine belongs to Antibacterials group whose information about Brand can be referenced from   Book : Martindale    Page : 282   Edition : 37   Martindale    Page : 282   Edition : 37  

  ►   Brandname : Bactrim, Ciplin, Colizole, Cotrimol, Oriprim, Sepmax, Fectrim, Septrin, Bactrim, Cotrim, Septra, SMZ-TMP, Sulfatrim, Bactrimel, Bioprim, Blaxezan, Cotribene, Eusaprim
  ►  Strength : with

Reference of this Medicine for its Strength can be taken from   Book :    Page :    Edition :   
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
Reference :-   Book : Martindale    Page : 281   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 Bacterial infections Oral 960 mg b.d. (trimethoprim 160 mg and sulfamethoxazole 800 mg) twice daily. In severe infections 2.88 g daily in 2 divided doses has been given.
2 Pneumocystis pneumonia Oral 120 mg/kg Given daily in 2 to 4 divided doses for 14 to 21 days
3 Prophylaxis of pneumocystis pneumonia Oral 960 mg o.d. Given (7 days each week:; 960 mg once daily on alternate days (3 days each week); or 960 mg twice daily on alternate days (3 days each week).

Ref :-  Book : Martindale    Page : 280   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 Prophylaxis of pneumocystis pneumonia 6 Week 6 Month Oral 120 mg Tablet b.d.
2 Prophylaxis of pneumocystis pneumonia 6 Month 6 Year Oral 240 mg Tablet b.d.
3 Prophylaxis of pneumocystis pneumonia 6 Year 12 Year Oral 480 mg Tablet b.d.
4 Prophylaxis of pneumocystis pneumonia IV 18 mg/kg Injection b.d.
5 Treatment of pneumocystis pneumonia oral or i.v 120 mg/kg
6 Prophylaxis of pneumocystis pneumonia oral or i.v 30 mg/kg
7 Leukemia or lymphoma Oral / i.v 30 mg/kg

Ref :- Book : Martindale    Page : 282   Edition : 37  
►  Side Effect : Nausea, Vomiting, Anorexia, Diarrhoea, Hypersensitivity reactions, Rashes, Pruritus, Photosensitivity reactions, Exfoliative dermatitis, Erythema nodosum, Toxic epidermal necrolysis, Stevens-Johnson syndrome, Dermatitis, Interstitial nephritis, Tubular necrosis, Lumbar pain, Haematuria, Oliguria, Anuria, Agranulocytosis, Aplastic anaemia, Thrombocytopenia, leucopenia, Hypoprothrombinaemia, Eosinophilia, Syndrome resembling serum sickness, Hepatic necrosis, Hepatomegaly, Jaundice, Myocarditis, Pulmonary eosinophilia, Fibrosing alveolitis, Vasculitis, Polyarteritis nodosa, Hypoglycaemia, Hypothyroidism, Neurological reactions, Aseptic meningitis, Ataxia, Benign intracranial hypertension, Convulsions, Dizziness, Drowsiness, Fatigue, Headache, Insomnia, Mental depression, Peripheral or optic neuropathies, Psychosis, Tinnitus, Vertigo, Pancreatitis, Pseudomembranous colitis, Glossitis, Rises in serum creatinine and blood-urea nitrogen, Angioedema, Depression of haematopoiesis, Megaloblastic anaemia, Leukopenia, Methaemoglobinaemia
Ref :-   Book : Martindale    Page : 280, 369, 386   Edition : 37.  

►  Drug Interaction : Drug interaction of Sulfamethoxazole and Trimethoprim (Co-trimoxazole) is with , , Oral anticoagulants, NSAIDS, , , Angiotensin conveting enzyme inhibitors ,  Procaine, Methotrexate, Phenytoin , Digoxin , Procainamide , Rosiglitazone , Repaglinide , Warfarin , Zidovudine, Zalcitabine, Lamivudine, Dapsone , Pyrimethamine
Ref :-   Book : Martindale    Page : 281,370,386   Edition : 37.  

  ►    Mechanism of Drug Drug Interaction :  The action of sulfonamides may be antagonised by paminobenzoic acid and its derivatives, particularly potassium aminobenzoate and the procaine group of local anaesthetics. Sulfamethoxazole and other sulfonamides may potentiate the effects of some drugs, such as oral anticoagulants , methotrexate, and phenytoin; this may be due to displacement of the drug from plasma protein binding sites or to inhibition of metabolism. However, the clinical significance of these interactions appears to depend on the particular sulfonamide involved. The possibility of interactions with other highly protein-bound drugs, such as NSAIDs, should be considered. High doses of sulfonamides have been reported to have a hypoglycaemic effect; the antidiabetic effect of the sulfonylurea compounds may be enhanced by sulfonamides. 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 : 281,370,386   Edition : 37.  

►  Contraindication : Hypersensitivity, Hepatic impairment, Renal impairment, Folate supplementation may be necessary in patients predisposed to folate deficiency, such as elderly patients and when high doses of co-trimoxazole are given for a prolonged period. Co-trimoxazole is contra-indicated in patients with megaloblastic anaemia due to folate deficiency., Treatment with sulfonamides should be stopped immediately a rash appears because of the danger of severe allergic reactions such as the Stevens-Johnson syndrome., Sulfamethoxazole should not be given to patients with a history of hypersensitivity to sulfonamides as cross-sensitivity may occur between drugs of this group. Care is generally advisable in patients with a history of allergy or asthma, Caution is also needed in the elderly, who may be more likely to have other risk factors for reactions. Some consider Silver sulphadiazine to be contra-indicated in lupus erythematosus as it may exacerbate the condition., Sulfamethoxazole and other sulfonamides are not usually given to infants within 1 to 2 months of birth because of the risk of producing kernicterus; for the same reason, they are generally contra-indicated in women prior to delivery, Patients with AIDS may be particularly prone to adverse reactions, especially when sulfamethoxazole is given with trimethoprim as co-trimoxazole, Sulfonamides have been reported to interfere with some diagnostic tests, including those for urea, creatinine, and urinary glucose and urobilinogen.
Ref :-   Book : Martindale    Page : 280,369,386   Edition : 37.  
  ►  Mechanism of Action :   Co-trimoxazole is a mixture of the sulfonamide, sulfamethoxazole, and the diaminopyrimidine, trimethoprim, in the proportion of 5 parts of sulfamethoxazole to 1 part of trimethoprim. The antimicrobial activity of the combination of trimethoprim and sulfamethoxazole results from its actions on two steps of the enzymatic pathway for the synthesis of tetrahydrofolic acid. Sulfonamide inhibits the incorporation of PABA into folic acid, and trimethoprim prevents the reduction of dihydrofolate to tetrahydrofolate. Tetrahydrofolate is essential for one-carbon transfer reactions (e.g., the synthesis of thymidylate from deoxyuridylate). Selective toxicity for microorganisms is achieved in two ways. Mammalian cells use preformed folates from the diet and do not synthesize the compound. Furthermore, trimethoprim is a highly selective inhibitor of dihydrofolate reductase of lower organisms: ~100, 000 times more drug is required to inhibit human reductase than the bacterial enzyme. This relative selectivity is vital because this enzymatic function is essential to all species. Reference: Goodmann, pg. no..1468 ed. 12.
Ref :-   Book : Martindale    Page : 281   Edition : 37.  

Pathway of DIETARY Product

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

  ►  Pathway with its reference as follows :-
  • Nimbidin have Anti-malerial property --- ( Prophylatic Potential of Lemon Grass and Neem as Antimalarial Agents. (2010). Journal Of American Science, 6(8). )
  • Triterpene Saponins has the ability to release endogenous secretion, which is potetial mediator of the antulcer actions. --- (: Abbas, A. (2015). Antimicrobial potential of glycchariza glaba. Journal Of Drug Design And Medicinal Chemistr, 1(2). )
  • Estragole have antibiotic property --- (Duke, J. & Duke, J. (2002). Handbook of medicinal herbs. Boca Raton, FL: CRC Press. )
  • Nimbin have Anti-malerial property --- (Kokate, C. (2013). Pharmacognosy (4th ed.). Pune: Nirali Prakashan. )

  •   ►  URL --
  • .
  • +J.+%26+Duke .
  • +J.+(2002).+Handbook+of+medicinal+herbs.+Boca+Raton .
  • +FL:+CRC+Press.&hl=en&sa=X&redir_esc=y#v=onepage&q=Duke%2C%20J.%20%26%20Duke%2C%20J.%20(2002).%20Handbook%20 .
  • Kokate .
  • C. (2013). Pharmacognosy (4th ed.). Pune: Nirali Prakashan. .
  • .
  • .

  • DIETARY Substance Interactions

    ​   ► This Medicine interact with :- VITAMIN K with Decrease in Nutrient Level.   FOLIC ACID with Decrease in Nutrient Level.  

      ►  Reference :-
  • Gaby, A. (2006). A–Z Guide to Drug-Herb-Vitamin Interactions. 2nd ed. New York: Three Rivers Press

  •   ►  URL --

    ContraIndication DIETARY Substance

    ​   ► This Medicine contraindicate with :- NA

    ►   Route of Elimination :   Hepatic (Metabolism), Renal, Faecal
    Ref :-   Book : Martindale    Page : 370, 387   Edition : 37.  

    ►    Plasma Half-life :   Min value :-   NA    Max value :-   NA

    ►    Peak Plasma Concentration :   Min value :-   NA    Max value :-   NA