Bacfar

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Medically reviewed

Marina Burgos

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Bacfar

Property Description
Active Ingredient Sulphamethoxazole and Trimethoprim (Co-trimoxazole)
Forms Tablet, Oral suspension, Intravenous solution
Pharmacological Class Antibiotic (Sulfonamide/Dihydrofolate Reductase Inhibitor)
Common Use Treating bacterial and certain protozoal infections
Origin Synthetic

What is Bacfar and its Core Identity?

Bacfar is the trade name for Co-trimoxazole, a widely recognized synthetic antibiotic designated as a fixed-dose combination antimicrobial agent. This drug is formally classified as belonging to the Sulfonamide/Dihydrofolate Reductase Inhibitor pharmacological group, which defines its mechanism against susceptible pathogens. This classification confirms that the medicine works by interfering with the vital chemical pathways inside the targeted bacteria. This combination has been clinically recognized for its reliable efficacy against a broad spectrum of common bacterial pathogens, supporting its consistent use in various clinical settings.

What is Bacfar Made of and What Forms are Available?

The medicine’s composition consists of two primary active ingredients: Sulphamethoxazole and Trimethoprim. Both chemical entities are synthetic compounds that have been intentionally paired to create a mutually reinforcing therapeutic effect. This combined product is manufactured in several key pharmaceutical preparations, including the common tablet form (often in double-strength formulations), a liquid oral suspension specifically formulated for children and patients who have difficulty swallowing solids, and a sterile solution suitable for intravenous (IV) administration.

What is the General Purpose of this Synergistic Combination?

The general purpose of Co-trimoxazole is the highly efficient elimination of susceptible bacteria and certain protozoa that cause infection. This efficiency is achieved because the two components act synergistically, blocking two consecutive steps in the pathogen’s essential metabolic pathway related to folate synthesis. This combined action is designed to be more powerful than using either ingredient alone, ensuring a stronger treatment effect. By interrupting this crucial process required for the production of bacterial DNA and proteins, the drug rapidly exerts a powerful bactericidal (bacteria-killing) effect, thereby reducing the infectious load.

What side effects are possible with Bacfar?

Possible Side Effects and Safety Information

This section summarizes the adverse reactions and safety information documented in official government regulatory labeling for Bacfar (baclofen).

Frequency-Classified Adverse Reactions

The most common documented side effects are categorized by frequency:

  • Very Common (Affecting 1 in 10 or more): Drowsiness (often transient), Muscle Weakness.
  • Common (Affecting 1 in 100 to less than 1 in 10): Dizziness, Fatigue, Nausea, Headache, Insomnia, Confusion, Hypotension (low blood pressure), and Gastrointestinal issues such as Constipation.

Adverse reactions affecting various body systems are listed, including the Nervous System, Gastrointestinal Tract, and Renal/Urinary System.

Serious Adverse Reactions and Key Constraints

Official documents highlight rare but clinically serious adverse reactions and critical safety constraints:

  • Abrupt Withdrawal Risk: Suddenly stopping this medication can lead to a severe and potentially life-threatening withdrawal syndrome, which may include hallucinations, high fever, seizures, and exaggerated spasticity, rarely advancing to rhabdomyolysis and multi-organ failure. The dosage must be reduced slowly under supervision.
  • Encephalopathy: Serious brain toxicity has been documented, particularly in patients with pre-existing renal impairment (kidney problems).
  • Population Safety: Elderly patients and those with kidney impairment are at higher risk for central nervous system side effects and toxicity, often requiring cautious dosing and close monitoring.
  • Interactions: The CNS depressant effects of Bacfar are additive with alcohol and other CNS-acting medicines, requiring caution regarding impaired alertness.

Overdose and Emergency Response

Overdose of Bacfar (Co-trimoxazole) is documented in regulatory sources and can manifest acutely or chronically. Acute overdosage may present with gastrointestinal symptoms such as vomiting and anorexia, alongside systemic effects including fever, dizziness, and confusion, potentially progressing to loss of consciousness. Signs of organ toxicity like hematuria (blood in urine) and jaundice are officially cited as severe manifestations.

Immediate medical help must be sought for any suspected overdose. Regulatory documents explicitly instruct individuals to contact a Poison Control Center or seek emergency medical attention immediately.

In the case of significant ingestion, official treatment procedures include gastric lavage or forced emesis. Management is officially described as symptomatic and supportive. While no specific antidote is known, corrective treatment is documented for specific toxic effects. For instance, if bone marrow depression occurs—a risk associated with chronic overdosage—administration of leucovorin (folinic acid) is the necessary corrective measure. Monitoring of blood counts, serum potassium, and maintenance of adequate fluid intake are required procedures to mitigate risks like crystalluria, particularly in patients with pre-existing renal impairment. The drug is contraindicated in infants younger than two months due to toxicity risk.

Therapeutic Uses of Bacfar

What Bacfar Treats: Main Uses and Benefits

Bacfar (Co-trimoxazole) is a combination antibiotic used to combat a wide spectrum of susceptible bacterial and certain parasitic infections. The medication is commonly used across conditions presenting with acute or disruptive episodes. Its therapeutic value is relevant for managing acute symptomatic episodes and may be part of symptomatic management for high-risk situations.

Core Therapeutic Contexts

The medicine is commonly used in clinical settings that involve acute or unstable symptom patterns, applying to conditions where heightened symptoms interfere with daily functioning. The conditions where it may assist with management include genitourinary infections like cystitis and pyelonephritis, respiratory tract conditions such as acute bronchitis exacerbations, specific severe pneumonia types, and gastrointestinal issues like shigellosis and traveler's diarrhea. For immunocompromised patients, it is also considered relevant for addressing opportunistic infections like Pneumocystis Jirovecii Pneumonia (PJP).

“The medication is relevant for easing symptoms that interfere with daily comfort and is used when groups of symptoms appear suddenly or fluctuate.”

The primary benefit is relevant for addressing the underlying infection, which contributes to improved comfort and may assist with maintaining functional stability during periods of heightened symptoms.


Quick Fact: Support for Symptoms Related to Systemic and Localized Discomfort

Bacfar supports the patient by addressing symptoms related to systemic imbalance (fever) and organ-specific functional stress (painful urination, diarrhea, or shortness of breath).

Eligibility and Restrictions for Use

Who Can and Cannot Use Bacfar?

Bacfar (Co-trimoxazole) is a prescription antibiotic with specific population eligibility rules defined by regulatory authorities.


Official Eligibility and Contraindications

Classification Official Regulatory Statements
Absolute Contraindications Must not be used in patients with known hypersensitivity to the active ingredients; individuals with folate-deficiency megaloblastic anemia; or those with severe liver damage or severe renal insufficiency (CrCl <15 mL/min).
Infants during the first 6 weeks of life (some sources state <2 months) are ineligible, as are pregnant patients at term (near delivery).
Conditional Use Patients with moderate renal impairment (CrCl 15 to 30 mL/min) are eligible but require a reduced dosage and careful monitoring.
Use in geriatric patients requires caution due to an increased risk of adverse reactions and comorbidities.
Reproductive Status The medicine is contraindicated at term pregnancy and generally not recommended for mothers nursing infants <2 months of age.

Populations Explicitly Allowed

Bacfar is approved for use in adults and pediatric patients ge 2 months of age for specific indications, provided none of the absolute contraindications are present.

What should I know about interactions with other medicines?

Bacfar’s interaction profile is officially defined by its combined effects on drug elimination pathways and specific additive pharmacodynamic risks, as documented in regulatory labeling.

Contraindicated Combinations and Exposure Modification

The co-administration of Bacfar with Dofetilide is strictly prohibited in regulatory documents due to the documented risk of life-threatening ventricular arrhythmias, stemming from trimethoprim's inhibition of the Organic Cation Transporter 2 (OCT2). This OCT2 interference also increases the plasma concentrations of other substrates, including Metformin, Amantadine, and Memantine. Furthermore, the drug prolongs the half-life of Phenytoin and increases the systemic exposure of Digoxin; this increase in Digoxin exposure is specifically noted to be more pronounced in elderly patients.

Metabolic and Pharmacodynamic Interactions

Bacfar can potentiate the effects of certain medicines through enzyme inhibition. Sulfamethoxazole inhibits CYP2C9 and trimethoprim inhibits CYP2C8, affecting the metabolism of medicines like Warfarin and specific oral hypoglycemics, which increases the risk of their respective effects. A crucial pharmacodynamic interaction exists with Methotrexate, where the additive anti-folate mechanism increases the formal risk of bone marrow depression. Additionally, co-administration with ACE Inhibitors, ARBs, or potassium-sparing diuretics can lead to clinically significant hyperkalaemia due to the trimethoprim component’s effect on renal potassium excretion. There is also a noted theoretical risk of a disulfiram-like reaction with alcohol consumption.

Mechanism of Action

How Bacfar Works: Dual Enzymatic Blockade

The mechanism of Bacfar (Co-trimoxazole) involves the simultaneous inhibition of two sequential enzymes in the bacterial folate synthesis pathway, a metabolic process pathogens require to create DNA, RNA, and proteins.

Bacfar targets two consecutive bacterial enzymes: Dihydropteroate Synthase (DHPS) and Dihydrofolate Reductase (DHFR). The Sulphamethoxazole component acts first, as a competitive inhibitor of DHPS, halting the formation of dihydrofolic acid. The Trimethoprim component acts second, as a reversible inhibitor of DHFR, preventing the creation of the active folate cofactor, tetrahydrofolic acid.

This dual-action mechanism rapidly depletes the microbial cell of the necessary building blocks (purines and thymidine) for nucleic acid synthesis. The combined sequential inhibition exhibits synergistic action, meaning the inhibitory effect is significantly greater than the sum of the individual actions. This metabolic interruption leads to a functional outcome shift from growth inhibition (bacteriostatic) to microbial cell killing (bactericidal). This cellular effect contributes to the elimination of susceptible microbial cells, unless the microbe has developed resistance mechanisms, such as producing altered target enzymes.

Dosage and Administration Information

How Bacfar (Co-trimoxazole) is Used

Bacfar, the trade name for Co-trimoxazole, is administered through specific routes and dosages determined by the type of infection. The medicine is primarily available for oral intake (as tablets or suspension) and for intravenous (IV) infusion.


Administration and Dosing

Administration is structured according to the severity and type of infection. The standard regimen for most acute infections is the Double Strength (DS) tablet (Sulphamethoxazole 800 mg / Trimethoprim 160 mg) taken at 12-hour intervals.

Usage Pattern Administration Detail Frequency/Duration
Oral Intake May be taken with food, and adequate fluid intake is recommended. Typically 3 to 14 days for acute courses.
IV Infusion IV concentrate must be diluted prior to use. It must be administered via slow infusion over 60 to 90 minutes. High-dose regimens (e.g., PJP treatment) are divided for use every 6 to 8 hours.

Population-Specific Procedural Rules

Use is established for pediatric patients aged two months and older, with dosing determined based on body weight. Adults with renal impairment require dosage adjustment. Specifically, for a creatinine clearance (CrCl) of 15 to 30 mL/min, the dosage is reduced by 50% or administered at extended intervals. If a dose is missed, it should be taken when remembered, but the next scheduled dose is not to be doubled.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Bacfar


Evidence for Use in Pneumocystis Jirovecii Pneumonia (PJP)

The research into Bacfar (Co-trimoxazole) for PJP consists of Randomized Controlled Trials (RCTs) and Systematic Reviews. These studies were used to investigate the medicine in two main contexts: the management of an active PJP infection and its long-term use for reducing incidence (prophylaxis). Researchers primarily measured survival outcomes (all-cause mortality) and monitored the rates at which PJP episodes occurred in high-risk groups, such as immunocompromised adults and children. What remains uncertain is the long-term impact on patients where resistance to the antimicrobial combination has emerged, which is an area of ongoing scientific inquiry.


Research Basis for Urinary Tract and Gastrointestinal Infections

The evidence base for this medicine in acute infections, such as symptomatic urinary tract infections (UTIs) and various forms of infectious diarrhea, includes findings from short-term Randomized Controlled Trials and ongoing surveillance studies. These studies focused on outcomes related to physical discomfort and systemic imbalance, primarily tracking bacteriological eradication (clearance of the bacteria from urine or stool) and the change in clinical symptoms. A key limitation is that the observed performance is highly influenced by regional variability in antimicrobial resistance of common pathogens like E. coli, which is continuously tracked in surveillance reports.


Studies for Malaria Prophylaxis and Treatment

The evidence exploring the role of this medicine in malaria comes from Systematic Reviews and controlled trials carried out in areas where the disease is widespread. Research examined its use for long-term reducing incidence (prophylaxis) and treatment, with studies primarily monitoring the incidence of clinical malaria episodes and the clearance of parasites from the blood. Evidence suggests that heterogeneity of results across varying geographical locations was observed in some studies, indicating that local factors may influence outcomes.


What Is Still Uncertain About the Research Evidence

The available evidence base highlights several areas where certainty remains low or where additional research is needed. For many acute treatment scenarios, follow-up durations were limited, meaning data for long-term outcomes or repeated treatments are still emerging. Evidence quality varies across studies, and results may not be directly comparable due to differences in sample sizes or study designs. Research continues to explore comparative data involving newer antibiotics.

Key Studies & References

  1. Low-dose trimethoprim-sulfamethoxazole treatment for Pneumocystis pneumonia: a systematic review and meta-analysis - Frontiers
  2. Co-trimoxazole and trimethoprim in complicated urinary tract infection - PubMed (Comparative RCT)

Frequently Asked Questions (FAQ)

Common questions about Bacfar (FAQ)

Q: What are the common infections Bacfar is used for?

A: Official regulatory documents state that Bacfar is prescribed for a range of bacterial infections. These typically include specific types of urinary tract infections (UTIs), Pneumocystis pneumonia (PJP), shigellosis, and traveler's diarrhea, provided the infection is caused by organisms susceptible to the medication.


Q: How long does Bacfar stay in your system after the last dose?

A: The body's elimination time is described in terms of the half-life of its two components. The half-life for both sulfamethoxazole and trimethoprim is generally reported to be around 8 to 11 hours. Full clearance can be influenced by factors like the medicine's half-life and the state of kidney function.


Q: What should I do if I forget to take a dose of Bacfar?

A: According to the official product information, regulatory instructions advise that a missed dose may be taken when it is remembered. However, it is explicitly advised not to double the next scheduled dose to make up for the dose that was missed.


Q: Can Bacfar cause a rash, and is that always serious?

A: Regulatory labeling lists skin reactions, such as a rash and urticaria (hives), among the reported adverse effects. While many rashes are mild, official warnings emphasize that more serious or fatal reactions have been reported. Official documentation emphasizes that the medication is typically discontinued at the first sign of a serious skin reaction, due to the risk of severe outcomes.


Q: Does Bacfar make you more sensitive to the sun?

A: Yes, official documents advise that Bacfar can increase photosensitivity, meaning there is a greater sensitivity to light. Official documents caution against unnecessary exposure to direct sunlight and recommend protective measures, such as clothing and sunscreens, to help manage the risk of photosensitivity.


Q: What happens if you drink alcohol while taking Bacfar?

A: Regulatory documents include a noted theoretical risk of a disulfiram-like reaction with alcohol consumption while taking Bacfar. A disulfiram-like reaction may cause unpleasant effects like flushing, headache, and nausea.


Q: Why is it true that Bacfar can interfere with blood thinners?

A: Bacfar can interfere with the way certain blood thinners, such as Warfarin, are metabolized (processed) by the body. This interaction occurs because the sulfamethoxazole component inhibits the CYP2C9 enzyme, which can increase the concentration and effect of the blood thinner in the body.


Q: Can Bacfar affect the results of blood tests?

A: Adverse reactions described in the labeling include hematologic toxicities. This means there is potential for changes in blood cell counts (such as platelets or neutrophils) that may be observed in lab test results.


Q: Can people with kidney problems use Bacfar safely?

A: The use of Bacfar is contraindicated (not recommended) in patients with severe renal insufficiency (very poor kidney function). Patients with moderate kidney impairment are eligible but often require a reduced dosage, and careful monitoring are required.


Q: Is Bacfar safe for use in children?

A: Official guidelines approve Bacfar for use in pediatric patients two months of age and older for specific indications. However, it is explicitly contraindicated in infants during the first six weeks of life. Administration protocols for children often account for body weight.


Q: Can older adults take Bacfar without special precautions?

A: No, official regulatory information advises that geriatric patients require caution. They are at an increased risk for certain adverse reactions, particularly involving the central nervous system and the risk of severe skin reactions, which may require closer monitoring.


Q: Can Bacfar cause problems with low blood sugar in some people?

A: The official product information notes that Bacfar can interfere with the metabolism of certain oral medicines used for diabetes. This potentiating effect increases the risk of hypoglycemia (low blood sugar) in those taking these specific diabetes medications.


Q: Why do some drug interactions with Bacfar involve potassium levels?

A: The interaction with potassium levels is due to the trimethoprim component, which can affect how the kidneys manage potassium excretion. This mechanism can lead to a risk of hyperkalaemia (abnormally high potassium levels), especially when Bacfar is taken with other medicines that also affect potassium.


Q: Does taking Bacfar with food help reduce stomach upset?

A: Regulatory instructions state that Bacfar may be taken with food. This is noted as an administration option.


Q: What is the mechanism of action of the trimethoprim component in Bacfar?

A: The trimethoprim component acts as an inhibitor of the enzyme Dihydrofolate Reductase (DHFR). By blocking this enzyme, it prevents bacteria from making the active folate cofactor they need to synthesize their DNA and proteins.


Q: Is Bacfar a broad-spectrum antibiotic?

A: Official product information describes Bacfar as having activity against a broad spectrum of both Gram-positive and Gram-negative bacteria. This range of activity meets the definition often used for a broad-spectrum antimicrobial agent.


Q: Can people with G6PD deficiency use Bacfar?

A: Regulatory documents state that Bacfar is contraindicated in patients with a history of or known predisposition to haemolysis (red blood cell destruction), such as individuals with G6PD deficiency.


Q: Why is it important to tell the doctor about a history of folate deficiency before taking Bacfar?

A: Bacfar works by interfering with the folate synthesis pathway in bacteria. Therefore, it is contraindicated in patients with known folate-deficiency megaloblastic anemia because of the risk that the medication could worsen this pre-existing condition.


Q: What are the symptoms of an overdose of Bacfar?

A: According to the official product information on overdosage, symptoms of an acute overdose may include severe nausea, vomiting, dizziness, and confusion. More serious effects like bone marrow depression or crystalluria (crystals in the urine) have also been reported.


Q: How is Bacfar eliminated from the body?

A: Both active ingredients of Bacfar are primarily eliminated from the body by the kidneys. This elimination process involves both glomerular filtration and renal tubular secretion, which are the main ways the body filters waste and foreign substances from the bloodstream.

How should Bacfar be stored and disposed of?

How to Store and Dispose of Bacfar (Co-trimoxazole)

Official regulatory guidelines define strict conditions for storing and disposing of Bacfar (Sulfamethoxazole and Trimethoprim) to maintain stability.

Storage Requirements

Condition Requirement
Temperature Store at controlled room temperature, 20 mathrmC to 25 mathrmC (68 mathrmF to 77 mathrmF).
Protection Must be kept protected from light and excess moisture.
Handling The oral suspension must not be refrigerated or frozen.
Container Keep the medicine in its original container, tightly closed, and away from excessive heat.
Child Safety Store the product out of the sight and reach of children.

Disposal Instructions

Unused or expired Bacfar should be discarded using a community drug take-back program when available. If not available, the product should be mixed with an unappealing substance, sealed in a container, and placed in household trash. It must not be flushed down a toilet or drain unless explicitly authorized by the labeling.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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