Sumetrolim

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Medically reviewed

Laura Arias

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 Sumetrolim

Quick Facts: Sumetrolim Identity

Property Description
Active ingredients Sulphamethoxazole, Trimethoprim
Form Tablet, Oral Suspension, IV Solution
Pharmacological class Combination Antibiotic, Anti-Infective Agent
General purpose Clearing susceptible bacterial infections
Origin Synthetic

Sumetrolim: A Definition and Pharmacological Class

Sumetrolim is a synthetic combination antibiotic medication, primarily known by its international non-proprietary name, Co-trimoxazole (or Cotrimoxazole). This medication is clinically recognized as an anti-infective agent for eliminating susceptible bacteria, functioning through dual-action efficacy. This dual-agent therapy is classified within the pharmacological groups of sulfonamide antibiotics and dihydrofolate reductase inhibitors.

This composition defines its position as a fixed-dose combination product, a feature that distinguishes it from antibiotics containing only a single active component. Co-trimoxazole is categorized as an essential medicine, underscoring its therapeutic importance.


Composition and Form: The Sulphamethoxazole-Trimethoprim Combination

The foundation of Sumetrolim's activity lies in its two active ingredients: Sulphamethoxazole (SMX) and Trimethoprim (TMP). These chemically synthesized compounds are specifically engineered to interact and enhance their antimicrobial effect. As a therapeutic option, Sumetrolim is supplied in multiple pharmaceutical preparations for both oral and clinical administration.

Dosage forms include tablets (often double strength) and an oral suspension for oral intake, in addition to an intravenous solution for administration via infusion. This combined approach is utilized for microbial control.


Action Profile: Synergism and General Anti-Infective Purpose

The drug’s general anti-infective purpose is fundamentally achieved through a synergistic mechanism. This means the combined action of Sulphamethoxazole and Trimethoprim delivers a potent bactericidal effect, which is substantially greater than the typically bacteriostatic effect (inhibiting growth) each ingredient provides alone. This action results from the two components blocking two sequential steps in the bacteria's vital folic acid synthesis pathway, efficiently preventing the bacteria from reproducing and ultimately serving its primary purpose of eliminating susceptible pathogens.

Regulatory References

  1. WHO Essential Medicines List
  2. NIH/NLM Drug Information

What side effects are possible with Sumetrolim?

Possible Side Effects and Safety Information

Sumetrolim (Co-trimoxazole) safety data is structured by regulatory bodies, classifying adverse reactions by frequency and the organ system affected. The most frequently documented adverse effects are generally gastrointestinal and dermatological in nature, such as nausea, vomiting, and skin rash, which are listed as Very Common or Common in regulatory documents.


Serious Adverse Reactions and Systemic Safety

Official prescribing information highlights the potential for rare but serious adverse reactions that primarily affect the blood and lymphatic system and the skin. These severe events include life-threatening blood disorders like Agranulocytosis and Aplastic Anaemia, as well as severe cutaneous reactions (SCARs), notably Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN). These severe reactions are typically classified as Rare or Very Rare.

Safety concerns also involve the Hepatobiliary and Renal Systems, with documented risks including Fulminant Hepatic Necrosis and Acute Renal Failure.


Population and Duration-Related Safety Patterns

The regulatory profile specifies safety constraints for certain populations. The drug is contraindicated in infants under 2 months of age and in patients with severe hepatic or severe renal impairment. Older adults are documented as having an increased susceptibility to severe side effects, including hyperkalemia and blood disorders. The highest risk period for the onset of severe cutaneous reactions is officially stated to be within the first weeks of treatment.

Overdose and Emergency Response

The official regulatory profile for Sumetrolim (Co-trimoxazole) overdose describes manifestations from both acute, single-dose ingestion and prolonged, excessive exposure. Acute overdose may present with signs of gastrointestinal distress, such as nausea, vomiting, and abdominal pain, along with neurological effects like dizziness and somnolence. Severe outcomes are documented, including the potential for crystalluria which can progress to acute kidney injury, and in extreme cases, convulsions.

Chronic, long-term overexposure may lead to serious hematological toxicity, specifically bone marrow depression, presenting as megaloblastic anemia, leukopenia, and thrombocytopenia. Official labeling notes that overdose manifestations may be more severe in elderly patients.

Regulatory guidance requires that immediate medical attention be sought in all suspected overdose cases. Hospital care and continuous monitoring are mandatory due to the risk of severe or life-threatening complications. No specific antidote is known for co-trimoxazole overdose. Management is officially defined as symptomatic and supportive treatment, which may include performing gastric lavage or administering activated charcoal if the ingestion is recent, and ensuring adequate fluid intake to promote renal excretion. The administration of leucovorin (folinic acid) may be required to counteract the hematological effects of the trimethoprim component.

Therapeutic Uses of Sumetrolim

What Sumetrolim Treats: Main Uses and Benefits

Sumetrolim (Co-trimoxazole) is an antibacterial agent commonly used to help manage infections across multiple body systems. In clinical settings, this medication provides support that helps ease the overall symptom burden across various acute conditions.

Therapeutic Scope and Core Benefit

The medication is commonly used for managing susceptible bacterial infections, such as those affecting the urinary tract (like cystitis and pyelonephritis), acute exacerbations of chronic bronchitis, and certain gastrointestinal illnesses (such as shigellosis or Traveler's Diarrhea). It is considered relevant in the management of severe opportunistic infections like Pneumocystis Jirovecii Pneumonia (PJP) and Toxoplasmosis, particularly in immunocompromised individuals. It contributes to improved comfort by assisting with symptomatic relief for pronounced symptoms such as painful urination and severe diarrhea, which supports general well-being during symptomatic phases.


Quick Fact: Relief for Acute Discomfort

Symptom Focus Therapeutic Support Provided
Urinary Symptoms Easing pain, burning, and urgency
GI Symptoms Supports resolution of severe diarrhea and cramping
Systemic Symptoms Helps ease fever and respiratory distress

Eligibility and Restrictions for Use

Who Can and Cannot Use Sumetrolim?

This section outlines the officially documented population eligibility and non-eligibility rules for Sumetrolim (Co-trimoxazole/Sulfamethoxazole-Trimethoprim), strictly according to regulatory labeling.


Contraindicated Populations (Must Not Use)

Contraindication Basis
Allergy Known hypersensitivity to trimethoprim or sulfonamides.
Hematologic Documented megaloblastic anemia due to folate deficiency, or a history of drug-induced immune thrombocytopenia.
Organ Damage Patients with marked hepatic damage or severe renal insufficiency when renal function status cannot be monitored.
Physiological State Pregnant patients and nursing mothers.
Pediatric Age Infants less than 2 months of age.

Restricted and Conditional Use

  • Age: Use in elderly patients (ge 65 years) requires special consideration due to the higher risk of kidney/liver issues and folate deficiency.
  • Kidney Function: Use is generally not recommended for patients with a Creatinine Clearance ( CrCl) below 15 mL/min. For CrCl between 15 and 30 mL/min, a reduced dosage is required.
  • Metabolic Conditions: Caution is necessary for patients with conditions such as G6PD deficiency, porphyria, or folate deficiency/malnutrition.

What should I know about interactions with other medicines?

Sumetrolim Interactions with other medicines and products

The official regulatory profile for Sumetrolim (Co-trimoxazole) is defined by pharmacokinetic and pharmacodynamic constraints that govern its co-administration with other substances. This information is based strictly on government-issued labeling.


Official Contraindicated Combinations

Certain medicinal products are strictly contraindicated due to unacceptable risk documented in prescribing information. This includes agents such as Dofetilide, due to the potential for QT interval prolongation and cardiac arrhythmias, and the antipsychotic agent Clozapine, due to the documented risk of neutropenia. Co-administration with the live BCG vaccine is also prohibited.


Pharmacokinetic and Pharmacodynamic Interference

The product has documented pharmacokinetic interference with several drug classes. It inhibits the metabolism of agents like Warfarin and Phenytoin, leading to an officially documented increase in INR and elevated serum levels, respectively. With antidiabetic agents, such as Sulfonylureas, this metabolic inhibition enhances the hypoglycemic effect.

Pharmacodynamic synergism is a significant domain. Combining the drug with ACE Inhibitors or Potassium-Sparing Diuretics creates an additive hyperkalaemic effect due to the Trimethoprim component's potassium-sparing action.


Exposure Modification and Restrictions

Trimethoprim significantly impacts Lamivudine exposure, with regulatory data reporting a substantial increase in its plasma levels. Furthermore, the risk of thrombocytopenia is specifically heightened for elderly patients concurrently taking Thiazide Diuretics. Regulatory documents specify that the product is contraindicated in cases of severe hepatic damage or severe renal insufficiency where plasma concentrations cannot be monitored.

Mechanism of Action

Sequential Blockade of Bacterial Metabolism

Sumetrolim, a combination of Sulfamethoxazole and Trimethoprim, exerts its effect by simultaneously blocking two crucial, consecutive steps in the bacterial folic acid synthesis pathway. This mechanism is highly selective, as human cells obtain folate exogenously, allowing the action to target microbial processes while sparing the host.

Targeted Enzyme Inhibition

Sulfamethoxazole acts as a competitive inhibitor of the bacterial enzyme Dihydropteroate Synthase (DHPS), while Trimethoprim inhibits Dihydrofolate Reductase (DHFR). The sequential interference with these two enzymes achieves a synergistic effect far greater than the individual components, leading to bactericidal activity.

Disruption of Microbial Genetic Material

The dual enzyme inhibition halts the production of tetrahydrofolic acid (THF). THF is essential for providing the one-carbon units required to synthesize purine and pyrimidine bases. The resulting deficiency in these building blocks causes an irreversible cessation of DNA and RNA production and protein synthesis, which ultimately arrests bacterial replication.

Dosage and Administration Information

Sumetrolim (Co-trimoxazole) is administered using regimens that define the route, dose, frequency, and total duration of use. The primary formulation for general use is the oral route, while an intravenous (IV) infusion is reserved for patients unable to take the medicine by mouth.

Official Dosing and Administration

For standard acute infections, the typical adult oral dose is 800 mg Sulfamethoxazole / 160 mg Trimethoprim (Double Strength tablet) taken every 12 hours. Treatment duration is condition-dependent, commonly ranging from 5 days (e.g., Shigellosis) to 10–14 days for acute urinary tract or respiratory infections. Higher, weight-based dosing (up to 20 mg TMP/kg/day) is prescribed for severe infections, administered every 6 to 8 hours.

Specific Use Requirements

Regardless of the dosage form, clinical practice involves maintaining adequate fluid intake to support proper drug excretion. IV administration is not given by rapid injection and must be diluted immediately prior to use and administered slowly over 60 to 90 minutes. The concentrate must not be given intramuscularly.

Creatinine Clearance (CrCl) Required Dose Adjustment (Adults)
Above 30 mL/min Usual standard dosage regimen
15 to 30 mL/min Half (1/2) the usual dosage regimen
Below 15 mL/min Use is generally not recommended

Dosage is also adjusted for age; the medication is typically not recommended for infants under two months of age. In the event of a missed dose, the standard practice involves taking the missed dose if it falls within a specific timeframe, or otherwise continuing with the next scheduled dose without doubling the amount.

Recent Clinical Evidence

Research evidence / Overview of Studies for Sumetrolim (Co-trimoxazole)


Evidence for Use in Pneumocystis Jirovecii Pneumonia (PJP)

Research has explored Sumetrolim's role in PJP, an infection that typically affects individuals with weakened immune systems. The body of evidence includes Randomized Controlled Trials (RCTs) and long-term observational cohort studies. These studies have monitored outcomes related to patient survival (mortality rates) and the rate at which the medicine prevents the initial infection or recurrence (prophylaxis) in adults and children with HIV/AIDS, and other patient groups studied in the research.

Findings describe patterns observed in maintaining an infection-free state over extended observation periods. What remains uncertain is the full understanding of outcomes in other immunocompromised groups, such as organ transplant recipients, which suggests data are still emerging regarding its role in diverse patient groups.


Evidence for Use in Urinary and Respiratory Infections

Research examined Sumetrolim's application in managing Urinary Tract Infections (UTIs) and Acute Exacerbations of Chronic Bronchitis. These studies primarily use RCTs and systematic reviews to compare different treatment approaches.

For UTIs, research explored short-term symptom changes, monitoring both the elimination of the pathogen (microbiological clearance) and outcomes related to physical discomfort, such as changes in painful urination. However, findings were mixed across studies, and current research highlights changes measured during the study period often reflect the specific local presence of bacterial resistance.

Studies exploring the treatment of acute exacerbations of chronic bronchitis monitored outcomes reflecting daily functioning, such as changes in cough and sputum. Research examined temporary physiological imbalance over treatment intervals typically lasting around 10 to 14 days.


Gaps, Limitations, and Research Uncertainty

The research record exists, yet certain gaps and limitations remain. One key uncertainty relates to antimicrobial resistance, which was observed in some studies. This ongoing development means older studies may not accurately reflect current real-world outcomes, and comparative evidence against the newest antibiotics is sometimes lacking.

Follow-up durations were limited in many acute treatment trials. Data for certain groups, such as pregnant populations, remain insufficient, and certainty remains low regarding long-term, specific outcomes across all potential patient groups.

Frequently Asked Questions (FAQ)

Common questions about Sumetrolim (FAQ)


Q: How quickly should I expect to feel better after starting Sumetrolim?

A: It is difficult to give a specific time for when symptom improvement will begin, as this can vary by individual and the type of infection being treated. Official product information notes that clinical studies typically monitor microbiological clearance and symptom reduction over the first few days of the treatment course.

Q: Can Sumetrolim cause skin sensitivity or a rash?

A: Regulatory documents classify skin rash as a common side effect of the medication. It is also noted that rare, serious skin reactions, such as Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN), are documented, with the highest risk period often cited as being within the first weeks of treatment.

Q: Is it true that Sumetrolim can cause sun sensitivity?

A: Yes, official warnings indicate that Sumetrolim can cause photosensitivity, which is an increased sensitivity to sunlight. Official prescribing information notes that precautions regarding sun exposure, such as using protective measures, are generally recommended during treatment.

Q: Can Sumetrolim be used for ear infections?

A: Yes, the medication is FDA-approved for the treatment of acute otitis media (acute ear infections) in children two months of age and older. This is based on the drug's effectiveness against common bacterial pathogens that cause these infections.

Q: What are the signs that Sumetrolim is working?

A: Sumetrolim is designed to kill susceptible bacteria. The expected clinical signs that the medication is working involve the resolution or noticeable improvement of symptoms, such as a reduction in fever or decreased pain/discomfort associated with the infection being treated.

Q: Are there any vitamins or supplements that interact with Sumetrolim?

A: Official warnings advise caution in patients who have folate deficiency or malnutrition, as the trimethoprim component can interfere with how the body uses folate (Vitamin B9). The official regulatory label focuses on drug-drug interactions, and interactions with specific supplements are not consistently cited.

Q: Can Sumetrolim be prescribed for bronchitis?

A: Yes, the medication is officially approved for the treatment of acute exacerbations of chronic bronchitis in adults. This use is based on its efficacy against the bacterial pathogens that commonly cause these flare-ups.

Q: How is Sumetrolim different from other sulfa drugs?

A: Sumetrolim (Co-trimoxazole) is a unique fixed-dose combination antibiotic. It contains a sulfa drug (Sulphamethoxazole) and a second agent (Trimethoprim). This combination allows the two components to work together in sequence, creating a synergistic effect that is different from using a single sulfa drug alone.

Q: What research shows Sumetrolim's effectiveness against Pneumocystis pneumonia?

A: The drug is a standard of care and is FDA-approved for the treatment and prevention (prophylaxis) of Pneumocystis jirovecii Pneumonia (PJP). This approval is supported by clinical trial data referenced in the product's official labeling, especially in immunocompromised patient populations.

Q: Why do some people feel tired or lethargic while taking Sumetrolim?

A: Official documents list certain central nervous system (CNS) effects as possible side effects. These effects, such as dizziness and headache, are possible side effects listed in the official documents that may be experienced by some patients.

Q: Is Sumetrolim effective against Staphylococcus infections?

A: Yes, regulatory documents generally list certain strains of Staphylococcus bacteria as susceptible to Sumetrolim. However, due to potential variability in bacterial resistance, the official labeling notes that susceptibility testing is often important for guiding treatment decisions.

Q: What are the specific requirements for IV administration of Sumetrolim?

A: Official administration instructions specify that the intravenous (IV) solution must be diluted immediately prior to use. It should be administered slowly over 60 to 90 minutes and is specifically restricted from being given as a rapid injection or into the muscle (intramuscularly).

Q: Does Sumetrolim interact with birth control pills?

A: Sumetrolim is not typically classified as an enzyme-inducing antibiotic, meaning it is not generally expected to reduce the efficacy of hormonal birth control like some other antibiotics. This information is intended for general guidance, and specific contraceptive planning is best discussed with a healthcare provider.

Q: How long does Sumetrolim stay in your system after stopping it?

A: The two active components, Sulfamethoxazole and Trimethoprim, have average half-lives of approximately 10 hours and 8 to 10 hours, respectively, in people with normal kidney function. Based on these half-lives, the drug is typically cleared from the system within a few days after the final dose.

Q: Is Sumetrolim effective against E. coli bacteria?

A: Yes, the medication is officially indicated for the treatment of infections caused by susceptible organisms, which include the common bacteria E. coli. E. coli is often responsible for infections like urinary tract infections (UTIs) and traveler's diarrhea.

Q: What happens if I miss a dose of Sumetrolim?

A: Official patient information advises that if a dose is missed, it should be taken as soon as it is remembered. However, if it is almost time for the next scheduled dose, the missed dose should be skipped to maintain the schedule. The regulatory documents specifically state that the dosage should never be doubled to make up for a missed dose.

Q: Is there a liquid form of Sumetrolim for people who can't swallow pills?

A: Yes. According to official dosage information, Sumetrolim is supplied in multiple forms for administration. These include tablets, an intravenous (IV) solution, and an oral suspension (liquid form) for those who may have difficulty swallowing solid medications.

Q: Can Sumetrolim affect my sleep?

A: Official information lists certain psychiatric and central nervous system effects as possible side effects. These effects, such as insomnia (trouble sleeping) and nervousness, are listed as possible psychiatric and CNS effects in the official product information.

Q: Why do doctors prescribe Sumetrolim for UTIs?

A: Doctors prescribe Sumetrolim for UTIs because it is an FDA-approved treatment option and its dual mechanism of action is effective against many common bacteria, such as E. coli, which cause these infections.

Q: Is it normal to feel a little dizzy after taking Sumetrolim?

A: Yes, dizziness is officially listed in regulatory documents as a possible side effect of the medication. Due to the potential for dizziness, official warnings advise caution regarding activities that require alertness, such as driving or operating machinery.

Q: Does taking Sumetrolim require extra fluid intake?

A: Yes. Official instructions require patients to maintain adequate fluid intake while taking this medication. This is a crucial step to help prevent the formation of crystals in the urine and ensure proper drug excretion from the body.

Q: Is Sumetrolim used in the treatment of traveler's diarrhea?

A: Yes, Sumetrolim is officially FDA-approved and is used for the treatment of traveler's diarrhea. It is specifically indicated for cases confirmed to be caused by susceptible strains of the bacteria E. coli.

How should Sumetrolim be stored and disposed of?

Storage and Disposal Requirements for Sumetrolim

Storage Conditions

Sumetrolim (sulfamethoxazole and trimethoprim) tablets must be stored at controlled room temperature, typically maintained between 20 C and 25 C (68 F and 77 F). The product must be kept out of the reach of children and protected from excessive moisture. Always store the medicine in a tightly closed container to ensure its stability.

Disposal Instructions

Unused or expired medication should be disposed of according to specific instructions provided on the drug label or by a local pharmacist. If a drug take-back program is unavailable, official guidelines recommend mixing the medicine with an undesirable substance, such as dirt or used coffee grounds, before placing it in a sealed bag and discarding it in the household trash. Do not flush the tablets down the toilet or pour them into a drain unless the labeling explicitly states it is safe to do so.

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

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