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Method of action:
Treatment option:
Medically reviewed by Militian Inessa Mesropovna, PharmD. Last updated on 22.03.2025

Attention! Information on this page is intended only for medical professionals! Information is collected in open sources and may contain significant errors! Be careful and double-check all the information on this page!
Top 20 medicines with the same components:
Purbac
Purbac contains two active ingredients that work in combination to enhance the antibacterial effect:
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Sulfamethoxazole – a sulfonamide group substance that inhibits folic acid synthesis in bacterial cells, disrupting microbial reproduction.
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Trimethoprim – enhances the effect of sulfamethoxazole by blocking the next stage of folic acid synthesis. As a result, bacteria lose their ability to grow and divide, leading to their destruction.
This combination makes Purbac effective against a wide range of bacterial infections, including strains resistant to other antibiotics.
Purbac is available in several forms to allow patients to take it in the most convenient way. Physicians prescribe the form based on the patient’s age, condition, and infection severity. For example, children find the suspension easier to take, while severe infections in hospitals may require injections.
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Tablets – the primary option for adults and adolescents. A standard tablet contains 400 mg of sulfamethoxazole and 80 mg of trimethoprim, while the Purbac Double Strength version contains 800 mg/160 mg. The tablets are film-coated, making them easier to swallow and gentler on the stomach.
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Oral suspension – a liquid form, primarily prescribed for children. Each 5 ml of suspension contains 200 mg of sulfamethoxazole and 40 mg of trimethoprim. The bottle must be shaken before use to evenly distribute the active ingredients. Thanks to its sweet taste, it is easier for young children to take.
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Injection solution – used for severe infections requiring rapid achievement of high blood concentration. Each 1 ml of solution contains 80 mg of sulfamethoxazole and 16 mg of trimethoprim. Injections are typically administered in hospitals under medical supervision.
The form of the drug affects not only convenience but also the speed of action. Tablets and suspensions begin working within 1–4 hours, while injections act almost immediately. The doctor selects the optimal form depending on the situation.
Purbac is prescribed for various bacterial infections sensitive to its active components. It effectively eliminates pathogens by disrupting their ability to reproduce. Physicians use it to treat infections of the respiratory tract, urinary system, gastrointestinal tract, skin, and soft tissues.
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Urinary tract infections (UTIs) (cystitis, pyelonephritis) – fights bacteria causing bladder and kidney inflammation in both acute and chronic cases.
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Respiratory tract infections (bronchitis, pneumonia) – used to treat bacterial infections of the bronchi and lungs, especially if the pathogens are susceptible to sulfamethoxazole and trimethoprim.
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Gastrointestinal infections (shigellosis, salmonellosis) – helps with intestinal infections that cause diarrhea, fever, and dehydration. Purbac inhibits the growth of pathogenic bacteria, easing the disease course.
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Skin and soft tissue infections (erysipelas, abscesses) – prescribed for bacterial skin inflammations, pustular lesions, and infected wounds.
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Toxoplasmosis – a parasitic infection, particularly dangerous for pregnant women and immunocompromised individuals. The drug is used as part of combination therapy.
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Pneumocystis pneumonia – prescribed for immunocompromised patients (e.g., those with HIV) to reduce the risk of severe lung inflammation caused by Pneumocystis jirovecii.
It is important to note that Purbac is only effective against bacterial infections. It is not used to treat viral diseases such as influenza or acute respiratory viral infections. Self-prescribing antibiotics can lead to bacterial resistance, so treatment should always be conducted under a doctor’s supervision.
Purbac is taken orally with a sufficient amount of water. Food intake does not affect its effectiveness; however, if you have a sensitive stomach, it is recommended to take the tablets after meals to reduce nausea and gastric irritation.
Dosage for adults and adolescents (from 12 years old)
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Standard regimen – 1–2 tablets (400 mg/80 mg) every 12 hours.
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For severe infections – the dose may be increased to 2 tablets twice daily (800 mg/160 mg).
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Course duration – usually 5 to 14 days, depending on the type and severity of the infection.
Dosage for children
The dosage for children depends on age and the dosage form:
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6 to 12 years – 1 tablet every 12 hours. If the child cannot swallow the tablet, the suspension can be used: 10 ml (2 teaspoons) twice daily.
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2 to 6 years – 5 ml (1 teaspoon) of suspension every 12 hours.
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Under 2 years – the drug is not prescribed for children under 2 months due to the risk of side effects.
Use in special cases
In some situations, Purbac is prescribed according to a specific regimen:
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Prophylaxis of Pneumocystis pneumonia – 1 tablet (400 mg/80 mg) once daily.
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Elderly patients – the physician may adjust the dose since kidney function decreases with age, which affects drug elimination. It is also important to monitor potassium levels, as Purbac may cause hyperkalemia.
Duration of treatment
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Mild to moderate infections – 5 to 7 days.
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Severe infections (pneumonia, complicated UTIs) – treatment may last up to 14 days.
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If symptoms persist or worsen, consult a doctor to adjust the treatment.
Important!
To ensure effective treatment, follow these recommendations:
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Do not skip doses – this can reduce the effectiveness of therapy and contribute to bacterial resistance.
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If you miss a dose, take it as soon as possible. If the next dose is soon, do not double it — simply continue according to the schedule.
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Drink plenty of water throughout the day – this helps protect the kidneys and reduce the risk of side effects.
Before starting treatment, it is important to ensure that the patient does not have conditions that contraindicate the use of Purbac. Certain diseases and individual characteristics may enhance side effects or make the medication unsafe.
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Hypersensitivity to sulfonamides or trimethoprim – If a patient has previously experienced an allergic reaction to these substances, taking Purbac again may cause rashes, angioedema, or anaphylactic shock.
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Severe liver or kidney dysfunction – In cases of significant impairment of these organs, the drug is not properly excreted, leading to accumulation and increased toxicity risk.
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Glucose-6-phosphate dehydrogenase (G6PD) deficiency – A rare hereditary condition where Purbac may cause hemolysis (destruction of red blood cells), leading to anemia and other complications.
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Pregnancy (especially in the first trimester and before childbirth) – The drug may interfere with fetal nervous system development, increasing the risk of congenital defects. In later stages, it can cause neonatal jaundice.
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Children under 2 months – In infants, enzyme systems are not yet fully developed, making metabolism of the drug unsafe.
Before prescribing Purbac, the physician assesses the patient’s overall condition and potential risks. If contraindications exist, alternative antibiotics that do not cause complications are selected.
If unusual symptoms, worsening health, or allergic reactions appear during treatment, the drug should be discontinued immediately, and a doctor should be consulted.
Purbac requires caution in prescribing, especially for patients with specific conditions or a predisposition to side effects. The doctor must consider possible risks and adjust the dosage or prescribe additional tests if necessary.
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Patients with a history of allergic reactions – If a person has had allergies to medications or foods before, there is a risk of a reaction to Purbac. Possible symptoms include rashes, itching, swelling, or even anaphylaxis.
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Folic acid deficiency – Long-term use of the drug can reduce folate levels in the body. This is especially important for elderly patients, pregnant women, and individuals with chronic blood disorders. In some cases, doctors may prescribe additional folic acid supplements.
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Monitoring kidney and liver function during prolonged treatment – Since the drug is primarily excreted through the kidneys, it may accumulate in patients with kidney impairment. Patients with chronic kidney and liver diseases should regularly undergo laboratory tests.
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Risk of superinfections – Prolonged antibiotic use can lead to the growth of resistant bacteria or fungi, requiring a change in treatment. If symptoms persist or new complaints appear, a follow-up medical consultation is necessary.
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Avoid UV exposure – Purbac increases skin sensitivity to sunlight (photosensitization), raising the risk of sunburn and irritation. During treatment, it is recommended to minimize sun exposure, wear protective clothing, and use sunscreen.
Additional monitoring is required for elderly patients, immunocompromised individuals, and those taking other drugs that interact with Purbac. If unusual symptoms or worsening health occur, consult a doctor to adjust the therapy.
Purbac may interact with other medications, enhancing or reducing their effects. This is particularly important for patients taking multiple drugs simultaneously, as improper combinations may lead to adverse effects.
Medications that may cause serious interactions with Purbac:
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Warfarin – Purbac enhances the anticoagulant effect of warfarin, increasing the risk of bleeding. Blood clotting levels (INR) should be monitored, and dosage adjustments may be necessary.
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Methotrexate – Increases methotrexate toxicity, which can lead to bone marrow suppression, anemia, leukopenia, and other hematological complications. Regular blood tests are required during co-administration.
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Phenytoin – Increases phenytoin concentration in the blood, raising the risk of side effects such as drowsiness, dizziness, ataxia (coordination disorders), and cognitive impairments.
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Diuretics (thiazide diuretics) – Co-administration increases the risk of thrombocytopenia, particularly in elderly patients, leading to bleeding tendencies, bruising, and coagulation disorders.
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Cyclosporine – Purbac may lower cyclosporine levels in the blood, reducing its immunosuppressive effect and increasing the risk of transplant rejection. Additionally, both drugs are nephrotoxic, placing a strain on the kidneys.
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Potassium supplements and ACE inhibitors (enalapril, lisinopril, captopril) – Co-administration with Purbac can lead to hyperkalemia (elevated potassium levels), increasing the risk of cardiac arrhythmias and heart problems.
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Oral hypoglycemic agents (glibenclamide, glipizide, gliclazide) – Purbac enhances their effect, which may cause a sharp drop in blood sugar levels, leading to hypoglycemia (dizziness, sweating, fainting). Diabetic patients should monitor glucose levels during treatment.
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Antiepileptic drugs (lamotrigine, carbamazepine) – May increase side effects and toxicity due to slower metabolism.
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Digoxin (cardiotonic agent) – Purbac can raise digoxin levels in the blood, particularly in elderly patients, increasing the risk of arrhythmias and toxicity.
Additional interactions:
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Hormonal contraceptives – Antibiotics, including Purbac, may reduce the effectiveness of oral contraceptives, so additional contraceptive methods are recommended.
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Vitamin C and hexamethylenetetramine (urotropin) – May increase the risk of crystal formation in the urine (crystalluria), particularly at high doses. This can cause urinary tract irritation and complications.
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Indomethacin and other NSAIDs – May increase Purbac concentrations in the blood, raising the risk of side effects.
Some drugs may weaken Purbac's action, reducing its effectiveness, so it is important to inform the doctor about all medications being taken, including over-the-counter and herbal products.
If unusual symptoms, worsening health, or side effects occur while taking Purbac, consult a doctor for possible therapy adjustments.
Purbac is not recommended during pregnancy and breastfeeding, as its active ingredients may affect fetal development and the health of a newborn.
Pregnancy
Purbac is contraindicated during pregnancy, especially in the first trimester and shortly before childbirth. This is due to the risk of fetal development abnormalities. The drug may interfere with folic acid metabolism, increasing the likelihood of congenital neural tube defects.
Additionally, late-term use of Purbac may lead to neonatal jaundice, a condition where bilirubin accumulates in the blood and may cause brain damage.
If antibacterial therapy is required during pregnancy, the doctor will select safer alternatives.
Breastfeeding
Purbac passes into breast milk and may cause jaundice, anemia, and allergic reactions in infants. Therefore, it is not recommended for use during breastfeeding. If treatment is necessary, the mother should temporarily discontinue lactation and switch the baby to formula feeding.
Effect on Fertility
Currently, there is insufficient data on the effect of Purbac on reproductive function in men and women. However, since the drug can disrupt folate metabolism, it theoretically may affect spermatogenesis and ovulation.
Purbac may cause dizziness, weakness, and reduced concentration, especially in the first days of use.
If these symptoms occur, it is advisable to avoid driving, operating machinery, or performing tasks requiring high attention levels. In patients with significant side effects, driving may be unsafe.
If severe fatigue, coordination issues, or confusion occur, the patient should inform their doctor.
Like any antibiotic, Purbac may cause adverse reactions affecting various body systems.
Gastrointestinal System
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Nausea, vomiting, diarrhea – the most common side effects. Taking the drug after meals and drinking plenty of water can help prevent them.
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Abdominal pain, indigestion – possible with prolonged use.
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Loss of appetite – occurs less frequently but may result from the drug’s effect on the digestive system.
Allergic Reactions
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Skin rash, itching, urticaria – the most common allergic manifestations.
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Photosensitivity – increased skin sensitivity to sunlight, leading to sunburn and irritation.
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Angioedema, anaphylactic shock – rare but serious complications requiring immediate medical attention.
Blood System
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Leukopenia (reduced white blood cell count) – may weaken the immune system and increase susceptibility to infections.
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Thrombocytopenia (reduced platelet count) – can lead to gum bleeding, bruising, and increased bleeding risk.
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Hemolytic anemia – especially in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency.
Nervous System
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Headache, dizziness – may occur in the first days of treatment and usually subside as the body adapts.
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Drowsiness or, conversely, anxiety – rare but possible in sensitive individuals.
Kidneys and Urinary System
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Crystalluria – formation of crystals in urine, which may irritate the urinary tract and cause discomfort.
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Elevated potassium levels (hyperkalemia) – may lead to heart rhythm disturbances, weakness, and numbness in the extremities.
Other Side Effects
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Chills, fever – may occur as a reaction to the drug.
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Muscle and joint pain – rare, but may resemble flu-like symptoms.
Taking Purbac in doses exceeding the recommended amount may lead to overdose, which presents with various symptoms depending on the drug quantity and individual characteristics.
Main Symptoms of Overdose
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Nausea, vomiting, diarrhea – due to irritation of the stomach and intestinal lining.
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Dizziness, weakness, confusion – associated with electrolyte imbalance and toxic effects on the nervous system.
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Bone marrow suppression – possible with significant overdose, leading to decreased white blood cell, platelet, and red blood cell counts, causing anemia, weakened immunity, and clotting disorders.
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Crystalluria and kidney damage – high doses of Purbac may cause crystal formation in the urine, increasing the risk of urinary tract irritation and kidney failure.
Overdose Treatment
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Gastric lavage – effective if the drug was taken recently, helping to reduce absorption.
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Forced diuresis – the patient is given plenty of fluids, and sometimes diuretics are administered to accelerate drug elimination.
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Electrolyte balance control – in cases of severe vomiting and diarrhea, intravenous fluid therapy may be necessary to prevent dehydration.
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Hemodialysis – used in severe cases when the kidneys are unable to excrete the drug, preventing toxic accumulation.
If overdose is suspected, seek medical help immediately, as severe complications may develop hours after excessive drug intake.
Purbac is a combined antibacterial drug with bactericidal activity. It kills bacteria by blocking their ability to reproduce.
Its pharmacological action is based on a combination of two active ingredients that act on different stages of folic acid synthesis in bacterial cells:
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Sulfamethoxazole inhibits the synthesis of dihydrofolic acid, which is essential for bacterial growth and reproduction.
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Trimethoprim inhibits the enzyme dihydrofolate reductase, preventing the conversion of dihydrofolic acid into its active form.
As a result, Purbac disrupts two consecutive stages in the biosynthesis of purines and nucleic acids—critical components for bacterial survival.
The drug is active against both Gram-positive and Gram-negative bacteria, including:
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Streptococcus pneumoniae
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Escherichia coli
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Klebsiella spp.
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Haemophilus influenzae
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Staphylococcus aureus
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Proteus mirabilis
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Enterobacter spp.
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Shigella spp.
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Salmonella spp.
This makes Purbac suitable for treating infections in the respiratory tract, urinary system, gastrointestinal tract, and skin.
The pharmacokinetics of Purbac determine its efficacy and dosing regimen:
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Bioavailability – approximately 90%. When taken orally, the drug is rapidly and almost completely absorbed from the gastrointestinal tract.
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Maximum blood concentration is reached within 1–4 hours after administration.
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Plasma protein binding – around 66% for sulfamethoxazole and 45% for trimethoprim.
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Half-life – 10–12 hours, allowing for twice-daily dosing.
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Metabolism – occurs in the liver, where both components undergo partial transformation.
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Excretion – primarily via the kidneys:
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30–50% of sulfamethoxazole is excreted unchanged.
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50–60% of trimethoprim is also excreted unchanged.
Due to high urinary concentrations, Purbac is especially effective for urinary tract infections. However, in patients with renal impairment, dose adjustment is necessary to avoid drug accumulation.
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Antibacterial agents, combination of sulfonamides and trimethoprim.
In addition to active ingredients, Purbac contains excipients that ensure stability, controlled release, and ease of use.
Key Components:
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Starch – serves as a filler, giving the tablet its required shape and structure.
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Magnesium stearate – functions as a lubricant, preventing the ingredients from clumping together and facilitating tablet manufacturing.
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Sodium starch glycolate – promotes rapid tablet disintegration in the stomach, ensuring even and complete release of active ingredients.
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Propylene glycol – acts as a solvent and stabilizer, improving the solubility of some components.
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Nipasol – a preservative that prevents drug degradation during storage.
The composition of excipients may slightly vary depending on the dosage form (tablets, suspension, injection solution).
Before use, check the composition, especially if the patient has allergies to excipients.
Purbac remains effective for 3 years from the date of manufacture. However, the shelf life may vary depending on the dosage form.
Always check the expiration date on the packaging before use. Expired medication should not be used, as it may lose therapeutic efficacy or become unsafe.
To maintain stability and effectiveness, Purbac must be stored properly:
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Tablets – store at a temperature below 25°C, in a dry place away from direct sunlight and moisture.
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Oral suspension – store in the refrigerator at 2–8°C. Do not freeze as this may alter its properties. Shake the bottle well before each use to evenly distribute active ingredients.
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Injection solution – store at room temperature, in a dark place, away from heat sources and direct light.
Always keep the medication out of reach of children to prevent accidental ingestion.
Purbac is available in different forms, each with its specific packaging. This is important for storage, accurate dosing, and safe administration.
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Tablets – packaged in blisters of 10 tablets, enclosed in a carton box. The number of blisters in a package depends on the dosage and treatment course. Tablets have a protective coating for easier swallowing.
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Oral suspension – supplied in a 100 ml bottle. A measuring spoon or dosing syringe may be included for accurate dosing. Shake the bottle before use.
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Injection solution – comes in 5 ml ampoules, used only in hospitals under medical supervision.
Before use, always inspect the packaging. If a blister is damaged, the suspension has changed color, or an ampoule contains sediment, do not use the medication. Instead, consult a pharmacist or doctor for a replacement.
Some patients require additional precautions when using Purbac. This is especially relevant for elderly individuals and those undergoing long-term therapy.
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Elderly patients are often advised to take folic acid supplements, as Purbac can reduce folate levels in the body. Folate deficiency may lead to anemia, fatigue, dizziness, and other complications. This is particularly important during prolonged antibiotic therapy.
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Do not use expired medication. Over time, active ingredients may degrade, making the drug not only ineffective but potentially unsafe.
How to dispose of the drug properly?
Antibiotics should not be thrown into household waste or flushed down the drain — this contributes to the spread of antibiotic-resistant bacteria in the environment.
The best approach is to inquire at a pharmacy or healthcare facility about where to safely return expired medications.
If the packaging is damaged or the medicine is no longer needed, dispose of it according to local sanitary regulations, not in a regular trash bin.
Purbac is officially registered and distributed in South Africa.
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Aspen Pharmacare (South Africa)
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The medication is available by prescription only.
Taking Purbac requires adherence to specific rules to ensure maximum safety and effectiveness of treatment. It’s important to follow your doctor's recommendations and avoid common mistakes that can reduce the drug’s efficacy or increase the risk of side effects.
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Use only as prescribed. Purbac is an antibiotic that requires precise dosing and course duration. Do not change the regimen on your own — this may reduce its effectiveness and contribute to bacterial resistance.
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Do not stop treatment prematurely. Even if symptoms disappear, it is important to complete the full course. Stopping too early can leave some bacteria alive, making the infection return in a more resistant form.
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Avoid prolonged sun exposure. Purbac increases skin sensitivity to UV radiation (photosensitization), which raises the risk of sunburn and irritation. If you must be outside, wear long-sleeved clothing and use sunscreen.
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Report side effects to your doctor. If you experience rash, itching, nausea, dizziness, or other unusual symptoms during treatment, consult your physician to adjust the therapy.
Following these recommendations will help minimize side effects and maximize treatment effectiveness. When used correctly, Purbac is a safe and effective option for treating bacterial infections.
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J01EE01 (Sulfamethoxazole in combination with trimethoprim).
A00.9 Cholera, unspecified
A01.0 Typhoid fever
A01.4 Paratyphoid fever, unspecified
A02 Other Salmonella infections
A09 Diarrhea and gastroenteritis of presumed infectious origin (dysentery, bacterial diarrhea)
A23.9 Brucellosis, unspecified
A39 Meningococcal infection
A42 Actinomycosis
A54 Gonococcal infection
A55 Chlamydial lymphogranuloma (venereal)
A56 Other sexually transmitted chlamydial diseases
A57 Chancroid
A74 Other diseases caused by chlamydia
A75 Typhus
B49 Mycosis, unspecified
B58 Toxoplasmosis
B59 Pneumocystis cystis
G00 Bacterial meningitis, not elsewhere classified categories
G04 Encephalitis, myelitis and encephalomyelitis
H60 Otitis externa
H66 Suppurative and unspecified otitis media
H70 Mastoiditis and related conditions
J02.9 Acute pharyngitis, unspecified
J03.9 Acute tonsillitis, unspecified (agranulocytic angina)
J06 Acute upper respiratory tract infection of multiple and unspecified sites
J11 Influenza, virus unidentified
J18 Pneumonia, unspecified
J22 Acute lower respiratory tract infection, unspecified
J32 Chronic sinusitis
J40 Bronchitis, not specified as acute or chronic
J42 Chronic bronchitis, unspecified
J47 Bronchiectatic disease [bronchiectasis]
J85 Lung abscess and mediastinum
J86 Pyothorax
K29.5 Chronic gastritis, unspecified
K52 Other noninfectious gastroenteritis and colitis
K81 Cholecystitis
K83.0 Cholangitis
L02 Skin abscess, furuncle and carbuncle
L03 Cellulitis
L08.0 Pyoderma
L08.9 Local infection of skin and subcutaneous tissue, unspecified
M60.0 Infectious myositis
M65 Synovitis and tenosynovitis
M65.0 Tendon sheath abscess
M71.0 Bursal abscess
M71.1 Other infectious bursitis
M86 Osteomyelitis
N12 Tubulointerstitial nephritis, not specified as acute or chronic
N15 Other tubulointerstitial diseases of kidney
N30 Cystitis
N34 Urethritis and urethral syndrome
N39.0 Urinary tract infection of unspecified site
N41.9 Inflammatory disease of prostate, unspecified
N49 Inflammatory diseases of male genital organs, not elsewhere classified
N70 Salpingitis and oophoritis
N73.9 Inflammatory diseases of female pelvic organs, unspecified
N74.3 Gonococcal inflammatory diseases of female pelvic organs (A54.2+)
N74.4 Inflammatory diseases of female pelvic organs due to chlamydia (A56.1+)
R09.1 Pleurisy
T79.3 Posttraumatic wound infection, not elsewhere classified
Z100* CHAPTER XXII Surgical practice