Biseptol is a complex antibacterial medicine, biseptol contains contrimoxazole-a mixture of sulfamethoxazole (sulfonamide with average duration of action) and trimethoprim with proper propprtion. These two components act on the same biochemical reaction chain to enhance the antibacterial effect and it inhibits the development of the bacterial resistance. The contrimoxazole acts on susceptible strains of Escherichia coli including the pathogenic strains, indolpozitivini strains of the Proteus spp. (including P. vulgaris), Morganella morganii, Klebsiella spp., Proteus mirabilis, Enterobacter spp., Haemophilus influenzas, Streptococcus pneumoniae, Shigella flexneri, S. sonnei, Neisseria gonorrhoeae and Pneumocystis jiroveci (P. carinii). These two components are rapidly absorbed by the gastrointestinal tract. These two components reach the maximum level of blood in 1 to 4 hours after oral administration. The both compounds are found in many tissues and body fluids in therapeutic concentrations.
biseptol category:

  • Human
  • Macrolides
  • Urinary Anti-Infectives


Companies and manufacturers of biseptol

  • Polfa Pabianice
  • Medana Pharma
  • Polfa Warszawa

Forms, composition and dosage

Biseptol is available at tablet, suspension and injection forms

  • Injectable; Injection; Sulfamethoxazole 80 mg; Trimethoprim 16 mg / ml
  • Suspension; Oral; Sulfamethoxazole 200 mg; Trimethoprim 40 mg / 5 ml
  • Tablet; Oral; Sulfamethoxazole 100 mg; Trimethoprim 20 mg
  • Tablet; Oral; Sulfamethoxazole 400 mg; Trimethoprim 80 mg

Pharmacological action of biseptol

This is the synthetic antimicrobial drug with broad spectrum bactericidal action; the sulfamethoxazole has the bacteriostatic action associated with inhibition of recycling process of PABA and violation dihydrofolic acid’s synthesis in the bacterial cells. The trimethoprim inhibits the enzyme involved in the metabolism of the folic acid converting dihydrofolate to thetetrahydrofolate. Thus t blocks the two successive stages of the biosynthesis of the purines and the nucleic acids essential for the growth and reproduction of the bacteria. High concentrations are created in the tissue of the lungs, kidney, prostate, bile, bones and cerebrospinal fluid.


After the oral administration sulfamethoxazole and the trimethoprim is rapidly absorbed by the gastrointestinal tract, meal slows their absorption and this is widely distributed in the tissues and the body fluids. The requirement of the trimethoprim to plasma proteins is 50%, sulfamethoxazole – 66%. T1/2 of trimethoprim is 8.6-17 hours, sulfamethoxazole – 9-11 hours.the trimethoprim and sulfamethoxazole are excreted by the urine in unchanged form and as metabolites.

Why is Biseptol prescribed?

  • Biseptol is prescribed for the infections-inflammatory diseases caused by the sensitive to co-trimoxazole microorganism.
  • This is also prescribed for the respiratory tract infections including acute and chronic bronchitis, empyema, bronchiectasis, lung abscess, pneumonia, tonsillitis, pharyngitis.
  • Urinary tract infections including gonococcal urethritis
  • Cystitis
  • Pyelonephritis
  • Prostatitis
  • Gastrointestinal infections including enteritis, typhoid, paratyphoid, dysentery, cholecystitis, cholangitis
  • Skin Infections and soft tissue including pyoderma, furunculosis, wound infection,
  • Septicemia
  • Brucellosis

Dosage information

Doses of biseptol are given on the basis of sulfamethoxazole, the average dose of the oral administration for adults and children older than 12 years is 0.4-2 g every 12 hours 2 times per day the course of treatment – 5-14 days. Orally for children aged 2-5 months – 100 mg 2 times per day; 1-2 years – 100 mg 2 times per day; 3-6 years – 200 mg 2 times per day; 6-12 years at 200-400 mg 2 times per day.

Side effects of biseptol

In digestive system:

  • Nausea
  • Vomiting
  • Diarrhea
  • Glossitis
  • Pseudomembranous colitis
  • Cholestatic hepatitis

Allergic reactions:

  • Skin rash
  • Angioedema
  • Stevens-johnson syndrome
  • Lyell’s syndrome

Hemopoietic system:

  • Leucopenia
  • Neutropenia
  • Thrombocytopenia
  • Agranulocytosis
  • megaloblastic anemia

Urinary system:

  • Crystalluria
  • Hematuria
  • Interstitial nephritis

Local reactions:

  • Phlebitis (when IV injected)


  • purpura
  • Impaired thyroid function.


  • Expressed disorders of liver and kidney function
  • blood diseases
  • deficiency of glucose-6-phosphate dehydrogenase
  • pregnancy
  • lactation (breastfeeding)
  • hypersensitivity to sulfonamides and trimethoprim

Using biseptol during pregnancy and breastfeeding

Sulfonamides and trimethoprim crosses the placenta and excretes in breast milk and they can develop kernicterus and hemolytic anemia in the fetus. In addition it increases the risk of fatty liver in pregnant women therefore the use of co-trimoxazole in pregnancy is contraindicated. Using of co-trimoxazole during lactation should be discontinued.

Biseptol in case of emergency / overdose


  • Anorexia
  • Nausea
  • Vomiting
  • Weakness
  • Abdominal pain
  • Headache
  • Drowsiness
  • hematuria
  • crystalluria


  • Gastric lavage
  • Fluid management
  • Correction of electrolyte imbalance
  • If necessary – hemodialysis.
    For chronic over dosage is characterized bone marrow suppression (pancytopenia). Treatment and prevention: the appointment of folic acid (5-15 mg daily)