What are sulfonamides. How do sulfonamides work. Which conditions can sulfonamides treat. What are the common side effects of sulfonamides. Are there any contraindications for sulfonamide use. How do sulfonamides compare to other antibiotics.

The Basics of Sulfonamides: A Powerful Class of Antibiotics

Sulfonamides are a class of synthetic bacteriostatic antibiotics that have been used for decades to treat various bacterial infections. These drugs work by inhibiting bacterial growth rather than directly killing the microorganisms. Their mechanism of action involves competitively inhibiting the conversion of p-aminobenzoic acid to dihydropteroate, a crucial step in bacterial folate synthesis.

Why is this mechanism important? Bacteria need folate for purine and DNA synthesis, which are essential for their survival and reproduction. By interfering with this process, sulfonamides effectively halt bacterial growth, allowing the body’s immune system to clear the infection.

Common Sulfonamides in Clinical Use

• Sulfisoxazole
• Sulfamethizole
• Sulfasalazine
• Sulfamethoxazole (often combined with trimethoprim as TMP/SMX)
• Sulfadoxine (combined with pyrimethamine)
• Silver sulfadiazine (topical)
• Mafenide (topical)
• Sulfacetamide (ophthalmic)

Mechanism of Action: How Sulfonamides Combat Bacterial Infections

Understanding the mechanism of action of sulfonamides is crucial for appreciating their effectiveness and potential limitations. These antibiotics target a specific pathway in bacterial metabolism that is not present in human cells, making them selective in their action.

How exactly do sulfonamides work at the molecular level? They act as competitive inhibitors of the enzyme dihydropteroate synthetase, which is responsible for incorporating p-aminobenzoic acid (PABA) into dihydropteroic acid, a precursor of folic acid. By mimicking the structure of PABA, sulfonamides bind to the enzyme’s active site, preventing the natural substrate from being utilized.

This interruption in folate synthesis has far-reaching consequences for bacteria. Without sufficient folate, bacteria cannot produce the nucleic acids necessary for DNA replication and RNA synthesis. As a result, bacterial growth and division are halted, effectively stopping the infection from spreading.

Why Humans Are Less Affected

An intriguing aspect of sulfonamides’ mechanism is their relative safety for human use. Unlike bacteria, humans do not synthesize their own folate. Instead, we obtain this essential nutrient from our diet. Consequently, our cells are much less affected by the inhibition of folate synthesis caused by sulfonamides. This difference in folate metabolism between bacteria and humans is what allows sulfonamides to be effective antibiotics with generally manageable side effects.

Spectrum of Activity: Which Pathogens Do Sulfonamides Target?

Sulfonamides exhibit a broad spectrum of antimicrobial activity, making them useful against a wide range of infectious agents. Their effectiveness extends beyond just bacteria, encompassing certain parasites as well.

Bacterial Targets

Which types of bacteria are most susceptible to sulfonamides? These antibiotics are active against many gram-positive and gram-negative bacteria. This broad coverage includes pathogens responsible for various common infections, such as urinary tract infections, respiratory tract infections, and certain skin infections.

Parasitic Targets

Interestingly, sulfonamides also show activity against some parasites. Notably, they are effective against:

• Plasmodium species: The parasites responsible for malaria
• Toxoplasma species: Causative agents of toxoplasmosis

This dual antibacterial and antiparasitic activity makes sulfonamides versatile agents in treating certain tropical and opportunistic infections.

Clinical Applications: When Are Sulfonamides Prescribed?

Given their broad spectrum of activity, sulfonamides find use in treating a variety of infections. However, due to increasing bacterial resistance and the availability of newer antibiotics, their use has become more specialized over time.

Common Indications for Sulfonamide Use

1. Urinary Tract Infections: Particularly when combined with trimethoprim (as TMP/SMX)
2. Nocardiosis: A rare bacterial infection that can affect the lungs, brain, and skin
3. Toxoplasmosis: Especially in immunocompromised patients
4. Chloroquine-resistant falciparum malaria: In combination with other antimalarial drugs
5. Inflammatory Bowel Disease: Sulfasalazine is used orally for this condition

Topical Applications

Sulfonamides also have important topical uses:

• Burns: Silver sulfadiazine and mafenide acetate creams are used to prevent and treat infections in burn wounds
• Vaginitis: Sulfanilamide in vaginal creams and suppositories
• Ocular Infections: Sulfacetamide in ophthalmic preparations for superficial eye infections

Pharmacokinetics: How Sulfonamides Move Through the Body

Understanding the pharmacokinetics of sulfonamides is crucial for their effective and safe use. These drugs generally have favorable properties that contribute to their clinical utility.

Absorption

How well are sulfonamides absorbed? Most sulfonamides are readily absorbed when taken orally. This high bioavailability means that a significant portion of the drug reaches the systemic circulation, allowing for effective treatment of systemic infections. Additionally, when applied to burns, sulfonamides can also be absorbed topically, providing both local and systemic effects.

Distribution

Once absorbed, sulfonamides are widely distributed throughout the body. They can reach therapeutic concentrations in most tissues and body fluids, including the cerebrospinal fluid. This extensive distribution contributes to their effectiveness against a variety of infections in different body sites.

Metabolism and Excretion

What happens to sulfonamides after they’ve done their job? The liver plays a primary role in metabolizing these drugs. Various enzymatic processes transform sulfonamides into metabolites, some of which may retain antimicrobial activity. The kidneys are responsible for excreting both the parent compounds and their metabolites. This renal excretion is an important consideration in patients with kidney dysfunction, as dosage adjustments may be necessary to prevent drug accumulation.

Drug Interactions

An important pharmacokinetic property of sulfonamides is their ability to compete for bilirubin-binding sites on albumin. This interaction can have significant clinical implications, especially in newborns or patients with liver disease. By displacing bilirubin from albumin, sulfonamides can potentially increase the risk of kernicterus in susceptible individuals.

Side Effects and Safety Concerns: What Risks Do Sulfonamides Pose?

While sulfonamides are generally well-tolerated, they can cause a range of side effects, some of which can be serious. Understanding these potential adverse reactions is crucial for safe prescribing and patient monitoring.

Common Side Effects

What are the most frequently reported side effects of sulfonamides? These typically include:

• Gastrointestinal disturbances: Nausea, vomiting, diarrhea
• Skin reactions: Rash, itching, photosensitivity
• Headache
• Dizziness
• Fatigue

Serious Adverse Reactions

While less common, sulfonamides can occasionally cause more severe reactions:

• Allergic reactions: Including anaphylaxis and Stevens-Johnson syndrome
• Blood disorders: Such as hemolytic anemia, especially in patients with G6PD deficiency
• Kidney problems: Crystalluria and kidney stones
• Liver toxicity: Ranging from mild enzyme elevations to severe hepatitis
• Central nervous system effects: Rarely, aseptic meningitis or encephalopathy

Special Populations

Certain groups require extra caution when prescribed sulfonamides:

1. Pregnant women: Evidence regarding birth defects is mixed, necessitating careful risk-benefit analysis
2. Newborns: Risk of kernicterus due to bilirubin displacement
3. Elderly patients: May be more susceptible to adverse effects
4. Patients with renal or hepatic impairment: May require dose adjustments

Resistance and Limitations: Challenges in Sulfonamide Use

Despite their broad spectrum of activity, sulfonamides face significant challenges in modern clinical practice, primarily due to the development of bacterial resistance.

Mechanisms of Resistance

How do bacteria become resistant to sulfonamides? Several mechanisms have been identified:

• Mutations in the dihydropteroate synthetase gene, reducing the enzyme’s affinity for sulfonamides
• Acquisition of plasmid-mediated resistant dihydropteroate synthetase genes
• Increased production of p-aminobenzoic acid, overwhelming the competitive inhibition
• Enhanced efflux of the drug from bacterial cells

Importantly, resistance to one sulfonamide typically indicates resistance to all drugs in this class. This cross-resistance limits the utility of switching between different sulfonamides in the face of treatment failure.

Clinical Implications of Resistance

The widespread nature of sulfonamide resistance has several consequences for clinical practice:

1. Reduced empiric use: Sulfonamides are less likely to be chosen for empiric therapy without susceptibility testing
2. Combination therapy: Often used with other antibiotics to overcome resistance and broaden coverage
3. Restricted indications: Use may be limited to specific infections where effectiveness is still high
4. Increased monitoring: Close follow-up and susceptibility testing are often necessary when using sulfonamides

Other Limitations

Beyond resistance, sulfonamides have other limitations:

• Ineffective against group A streptococci in pharyngitis
• Not suitable for treating anaerobic infections
• Potential for serious adverse reactions in some patients
• Drug interactions, particularly with anticoagulants and hypoglycemic agents

Comparison with Other Antibiotics: Where Do Sulfonamides Fit in Modern Practice?

To fully appreciate the role of sulfonamides in contemporary medicine, it’s essential to compare them with other antibiotic classes. This comparison helps in understanding when sulfonamides might be preferred and when other options might be more suitable.

Advantages of Sulfonamides

What unique benefits do sulfonamides offer compared to other antibiotics?

• Broad spectrum of activity, including some protozoal infections
• Oral and topical formulations available
• Generally affordable, especially older formulations
• Synergistic effects when combined with other drugs (e.g., trimethoprim)
• Effective for certain resistant pathogens when other antibiotics fail

Disadvantages Compared to Newer Antibiotics

Why might clinicians choose other antibiotics over sulfonamides in some cases?

• Higher rates of resistance for many common pathogens
• More frequent and potentially severe side effects compared to some newer antibiotics
• Less targeted spectrum of activity compared to newer, more specific antibiotics
• Not suitable for certain common infections (e.g., streptococcal pharyngitis)
• More drug interactions to consider

Specific Comparisons

How do sulfonamides stack up against other common antibiotic classes?

1. Beta-lactams (e.g., penicillins, cephalosporins):
   • Sulfonamides have a broader spectrum including some parasites
   • Beta-lactams are generally more effective against gram-positive bacteria
   • Beta-lactams have a better safety profile for many patients
2. Fluoroquinolones:
   • Both classes have broad-spectrum activity
   • Fluoroquinolones often have better tissue penetration
   • Sulfonamides may be preferred in some UTIs due to lower risk of resistance
3. Macrolides:
   • Macrolides are preferred for respiratory infections
   • Sulfonamides have better activity against many gram-negative bacteria
4. Tetracyclines:
   • Both classes have broad-spectrum activity including some atypical pathogens
   • Tetracyclines are often preferred for certain skin conditions
   • Sulfonamides may be safer in pregnancy (though still used with caution)

In conclusion, while sulfonamides have been largely supplanted by newer antibiotics in many clinical scenarios, they still retain an important place in the antimicrobial armamentarium. Their unique properties, including broad-spectrum activity and availability in various formulations, ensure their continued relevance in specific clinical situations. However, their use must be balanced against the risks of resistance and adverse effects, highlighting the importance of judicious prescribing and careful patient monitoring.

Sulfonamides – Infectious Diseases – Merck Manuals Professional Edition

By

Brian J. Werth

, PharmD, University of Washington School of Pharmacy

Reviewed/Revised May 2022 | Modified Sep 2022

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Topic Resources

Sulfonamides are synthetic bacteriostatic antibiotics Overview of Antibacterial Drugs Antibacterial drugs are derived from bacteria or molds or are synthesized de novo. Technically, “antibiotic” refers only to antimicrobials derived from bacteria or molds but is often (including… read more that competitively inhibit conversion of p-aminobenzoic acid to dihydropteroate, which bacteria need for folate synthesis and ultimately purine and DNA synthesis. Humans do not synthesize folate but acquire it in their diet, so their DNA synthesis is less affected.

Sulfonamides include the following:

• Mafenide

• Sulfacetamide

• Sulfadiazine

• Sulfadoxine

• Sulfamethizole

• Sulfamethoxazole

• Sulfanilamide

• Sulfasalazine

• Sulfisoxazole

Three sulfonamides, sulfisoxazole, sulfamethizole, and sulfasalazine, are available as single drugs for oral use. Sulfamethoxazole is coformulated with trimethoprim (as TMP/SMX Trimethoprim and Sulfamethoxazole Trimethoprim is available as a single drug or in combination with sulfamethoxazole (a sulfonamide antibiotic). The drugs act synergistically to block sequential steps in bacterial folate metabolism… read more ). Sulfadoxine combined with pyrimethamine is available for oral use.

Sulfonamides available for topical use include silver sulfadiazine and mafenide burn cream, sulfanilamide vaginal cream and suppositories, and sulfacetamide ophthalmic.

Sulfonamide resistance is widespread, and resistance to one sulfonamide indicates resistance to all.

Most sulfonamides are readily absorbed orally and, when applied to burns, topically. Sulfonamides are distributed throughout the body. They are metabolized mainly by the liver and excreted by the kidneys. Sulfonamides compete for bilirubin-binding sites on albumin.

Sulfonamides are active against

• A broad spectrum of gram-positive and many gram-negative bacteria

• Plasmodium Malaria Malaria is infection with Plasmodium species. Symptoms and signs include fever (which may be periodic), chills, rigors, sweating, diarrhea, abdominal pain, respiratory distress, confusion… read more and Toxoplasma Toxoplasmosis Toxoplasmosis is infection with Toxoplasma gondii. Symptoms range from none to benign lymphadenopathy, a mononucleosis-like illness, to life-threatening central nervous system (CNS) disease. .. read more species

Sulfasalazine can be used orally for inflammatory bowel disease Irritable Bowel Syndrome (IBS) Irritable bowel syndrome is characterized by recurrent abdominal discomfort or pain with at least two of the following characteristics: relation to defecation, association with a change in frequency… read more .

Sulfonamides are most commonly used with other drugs (eg, for nocardiosis Nocardiosis Nocardiosis is an acute or chronic, often disseminated, suppurative or granulomatous infection caused by various aerobic soil saprophytes of the gram-positive bacilli genus Nocardia…. read more , urinary tract infection Bacterial Urinary Tract Infections Bacterial urinary tract infections (UTIs) can involve the urethra, prostate, bladder, or kidneys. Symptoms may be absent or include urinary frequency, urgency, dysuria, lower abdominal pain… read more , and chloroquine-resistant falciparum malaria Treatment of Malaria in the United States ).

Topical sulfonamides can be used to treat the following:

• Burns Burns Burns are injuries of skin or other tissue caused by thermal, radiation, chemical, or electrical contact. Burns are classified by depth (superficial and deep partial-thickness, and full-thickness)… read more : Silver sulfadiazine and mafenide acetate

• Vaginitis Overview of Vaginitis Vaginitis is infectious or noninfectious inflammation of the vaginal mucosa, sometimes with inflammation of the vulva. Symptoms include vaginal discharge, irritation, pruritus, and erythema… read more : Vaginal cream and suppositories with sulfanilamide

• Superficial ocular infections: Ophthalmic sulfacetamide

Sulfonamides are contraindicated in patients who have had an allergic reaction to them or who have porphyria.

Sulfonamides do not eradicate group A streptococci in patients with pharyngitis and should not be used to treat group A streptococcal pharyngitis.

Evidence regarding an association between sulfonamides and birth defects is mixed. Animal studies with sulfonamides show some risk, and adequate studies have not been done in pregnant women.

Use near term and in breastfeeding mothers is contraindicated, as is use in patients kernicterus Kernicterus Kernicterus is brain damage caused by unconjugated bilirubin deposition in basal ganglia and brain stem nuclei. Normally, bilirubin bound to serum albumin stays in the intravascular space. However… read more in the fetus or neonate.

Sulfonamides enter breast milk.

Adverse effects of sulfonamides can result from oral and sometimes topical sulfonamides; effects include

• Hypersensitivity reactions, such as rashes, Stevens-Johnson syndrome Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) Stevens-Johnson syndrome and toxic epidermal necrolysis are severe cutaneous hypersensitivity reactions. Drugs, especially sulfa drugs, antiseizure drugs, and antibiotics, are the most common… read more , vasculitis, serum sickness, drug fever, anaphylaxis, and angioedema

• Crystalluria, oliguria, and anuria

• Hematologic reactions, such as agranulocytosis, thrombocytopenia, and, in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked enzymatic defect common in people with African ancestry that can result in hemolysis after acute illnesses or intake of oxidant… read more , hemolytic anemia

• Kernicterus in neonates

• Photosensitivity

• Neurologic effects, such as insomnia, and headache

Hypothyroidism, hepatitis, and activation of quiescent systemic lupus erythematosus may occur in patients taking sulfonamides. These drugs can exacerbate porphyrias.

Incidence of adverse effects is different for the various sulfonamides, but cross-sensitivity is common.

Sulfasalazine can reduce intestinal absorption of folate (folic acid). Thus, use of this drug may trigger folate deficiency in patients with inflammatory bowel disease, which also reduces absorption, especially if dietary intake is also inadequate.

Mafenide may cause metabolic acidosis by inhibiting carbonic anhydrase.

To avoid crystalluria, clinicians should hydrate patients well (eg, to produce a urinary output of 1200 to 1500 mL/day). Sulfonamides can be used in patients with renal insufficiency, but peak plasma levels should be measured and sulfamethoxazole levels should not exceed 120 mcg/mL.

Sulfonamides can potentiate sulfonylureas (with consequent hypoglycemia), phenytoin (with increased adverse effects), and coumarin anticoagulants.

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Sulfonamides: Types, Usage, Side Effects & More

Sulfonamides were the first antibiotics discovered and used, and have been used by doctors since the 1930s.

Also referred to as sulfa drugs, sulfonamides are man-made antibiotics that are used to treat bacterial infections.

If you are struggling with a UTI, bronchitis, pneumonia, or have an eye or ear infection that requires an antibiotic, your health care provider may prescribe you sulfonamides. 

In this article, I’ll explain what sulfonamides are, how they work, and what conditions they’re used to treat.

I’ll list some common sulfa drugs, and talk about their side effects and dosage.

I’ll also provide some precautions about these antibiotics, and tell you when you should talk to a doctor.

What are Sulfonamides?

Sulfonamides are a class of broad-spectrum antibiotics, meaning they work against a wide range of bacteria. 

How do Sulfonamides Work?

Sulfonamides, or sulfa drugs, are a class of broad-spectrum antibiotics that act on a wide range of gram-positive and gram-negative bacteria.

Sulfa drugs do not kill bacteria, but instead work by inhibiting the bacteria from growing and multiplying, thus stopping the infection.

They do this by stopping bacteria from making folic acid, which is necessary for their growth.

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What are Sulfonamides Used to Treat?

Sulfonamides have been around since the 1930s and were some of the first effective antibiotics to be introduced into clinical medicine.

Unfortunately, bacterial resistance to sulfonamides is now common, making them less effective against the most common bacteria.

Urinary tract infections

If you have a urinary tract infection (UTI) that is known to be susceptible to sulfonamides, you may be prescribed these antibiotics by your doctor.

UTIs occur when bacteria from the skin or rectum enter the urethra and infect the urinary tract.

A UTI can infect any part of the urinary system, including your kidneys, bladder, or urethra 

Bronchitis

Bronchitis is an infection of the lungs that causes the lining of your bronchial tubes to become inflamed.

While most cases of bronchitis are caused by a virus, it can sometimes also be caused by bacteria.

If you have persistent bronchitis, or other symptoms that lead your healthcare provider to suspect that it may be due to a bacterial infection, they may prescribe you antibacterial agents such as sulfonamides.

Eye infections

If you have a bacterial eye infection such as conjunctivitis, your doctor may prescribe you sulfonamides to treat it.

For eye infections, antibiotics are typically prescribed in the form of eye drops or ointment.

Bacterial meningitis 

Meningitis is a severe brain infection that can be viral or bacterial.

When it is caused by a bacteria called Listeria monocytogenes and the patient has an allergy to penicillin, sulfa drugs may be prescribed to treat meningitis. 

Pneumonia

If you are diagnosed with pneumonia, this means the air sacs of one or both lungs have become inflamed and may also be full of liquid or pus, making it difficult to breathe.

Pneumonia is caused by bacteria, fungi, viruses, or chemical irritants.

When pneumonia is caused by a bacterial infection, your doctor may prescribe sulfonamide antibiotics to treat it.

Ear infections

Sulfonamides are used to treat bacterial ear infections, especially in children.

The medication is usually a combination of erythromycin and sulfafurazole, and has been proven to be highly effective, with significant improvement within a few days.

Burns

If you have an extensive second or third-degree burn, you may contract a bacterial infection.

Sulfa drugs can help treat these infections and may sometimes be used prophylactically, especially when applied in the form of a cream to the affected skin.

Common Sulfonamides

Gantrisin 

Gantrisin (acetyl sulfisoxazole pediatric suspension) (sulfisoxazole) is an antibacterial sulfonamide used to treat bladder infections, ear infections, and meningitis.

It is available in liquid form, which is especially useful for pediatric patients.

It is also available as an eye drop or ophthalmic ointment.

Sulfadiazine

Sulfadiazine is usually prescribed in tablet form.

It is used to treat infections including urinary tract infections, ear infections and parasitic infections such as toxoplasmosis.

It can also help prevent rheumatic fever and meningitis.

Bactrim or Septra

Bactrim or Septra are two antibiotics (sulfamethoxazole and trimethoprim) that are usually prescribed together to treat common infections, including urinary tract infections and skin infections. 

Azulfidine

Sulfasalazine delayed-release (Azulfidine EN-tabs) is used to treat a specific type of bowel disease called ulcerative colitis.

It can also be used for rheumatoid arthritis in adults and children when other medications have not worked effectively.

Sulfasalazine is an anti-inflammatory drug that works by reducing inflammation in the body.

Zonegran

Zonegran is primarily used as an epilepsy medication.

It is used to prevent and control seizures in adults in conjunction with other medicines. 

Side Effects of Sulfonamides

Sulfonamides may cause you to have adverse reactions that require medical attention.

Common side effects you may experience from taking sulfonamides include:

• Lethargy
• Diarrhea
• Nausea 
• Vomiting
• Dizziness
• Headache
• Itchiness or skin rash
• Photosensitivity 

Less common side effects you might experience include:

• Aching muscles and joints
• Trouble swallowing
• Sore throat 
• Fever
• Unusual bleeding or bruising
• Yellow eyes or skin
• Pale skin

In rare circumstances, you may experience any of the following:

• Abdominal or stomach cramps, pain, or tenderness 
• Blood in urine
• Diarrhea that is watery or bloody
• Changes in urination: urinating a lot, or not at all
• Pain or burning when urinating
• Dehydration
• Mood changes
• Lower back pain
• Swelling of the front part of the neck

Always check with your healthcare professional if you have any of the above symptoms.

If you suspect you are having a serious allergic reaction or have overdosed, stop taking the medication immediately and call 9-1-1.

You can also report your symptoms to the FDA at 1-800-FDA-1088.

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Sulfonamides Precautions

Before taking sulfonamides, tell your doctor about all medical conditions you have, especially if you have any liver, kidney, or blood disorders.

Mention all prescription and non-prescription drugs that you are taking, including all herbal, nutritional, or dietary supplements.

Sulfa drugs should not be given to infants younger than two months old.

Tell your doctor if you are pregnant, planning on becoming pregnant, or are breastfeeding, as the drug can be passed through breast milk.

Sulfa drugs can cause a serious, even life-threatening, skin rash and make your skin extremely sensitive to the sun.

Avoid unnecessary sun exposure, and inform your healthcare provider immediately if you notice a rash or other unusual skin changes.

Always read all of the information on the prescription label and only take the medication as directed by your doctor or pharmacist.

Your dosage may change as your doctor monitors your body’s response to the medicine.

If you feel dizzy or nauseous, avoid driving or operating heavy machinery. 

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Frequently Asked Questions

What are examples of sulfonamides?

Sulfonamides include Gantrisin, Sulfadiazine, Bactrim or Septra, Azulfidine, and Zonegran.

Which drugs are sulfa drugs?

Sulfa drugs are broad-spectrum antibiotics that are used to treat a wide variety of bacterial infections. Sulfa drugs include Gantrisin, Sulfadiazine, Bactrim or Septra, Azulfidine, and Zonegran.

What are sulfonamides used for?

Sulfonamides inhibit the growth of harmful bacteria in the body. They are used to treat a variety of infections, including urinary tract infections, skin infections, lung infections, and other bacterial and parasitic infections.

What is the mechanism of action of sulfonamide?

Sulfonamides work by preventing bacteria from making folic acid, preventing their growth and reproduction.

K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

K Health has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions,
and medical associations. We avoid using tertiary references.

• How Sulfa Drugs Work. (2012).
  https://www.nih.gov/news-events/nih-research-matters/how-sulfa-drugs-work

• Sulfonamides. (2017).
  https://pubmed.ncbi.nlm.nih.gov/31643703/

• Sulfonamides. (2017).
  https://www.ncbi.nlm.nih.gov/books/NBK548382/

Sulfanilamide – description of the substance, pharmacology, use, contraindications, formula

Contents

• Structural formula

• Russian name

• English name

• Latin name

• chemical name

• Gross formula

• Pharmacological group of the substance Sulfanilamide

• Nosological classification

• CAS code

• pharmachologic effect

• Characteristic

• Pharmacology

• Application of the substance Sulfanilamide

• Contraindications

• Application restrictions

• Use during pregnancy and lactation

• Side effects of the substance Sulfanilamide

• Interaction

• Dosage and administration

• Precautionary measures

• Trade names with the active substance Sulfanilamide

Structural formula

Russian name

Sulfanilamide

English name

Sulfanilamide

Latin name

genus Sulfanilamidi)

Chemical name

4-Aminobenzenesulfonamide

General formula

C ₆ H ₈ N ₂ O ₂ S

Pharmacological group of the substance Sulfanilamide

Sulfonamides

Nosological classification

ICD-10 code list

CAS code

63-74-1

Pharmacological action

Pharmacological action 90 097-

antimicrobial .

Description

Refers to short-acting sulfa drugs. Sulfanilamide is a white, odorless, crystalline powder with a slightly bitter taste and a sweet aftertaste. Easily soluble in boiling water (1:2), difficult – in ethanol (1:37), soluble in solutions of hydrochloric acid, caustic alkalis, acetone (1:5), glycerin, propylene glycol; practically insoluble in ether, chloroform, benzene, petroleum ether. Molecular weight – 172.21.

Also used as sodium methane sulfate (Streptocide soluble) – white crystalline powder; soluble in water, practically insoluble in organic solvents.

Pharmacology

The mechanism of antimicrobial action of sulfanilamide is associated with the antagonism of PABA, with which it has a chemical similarity. Sulfanilamide is captured by the microbial cell, prevents the incorporation of PABA into dihydrofolic acid and, in addition, competitively inhibits the bacterial enzyme dihydropteroate synthetase (the enzyme responsible for the incorporation of PABA into dihydrofolic acid), as a result, the synthesis of dihydrofolic acid is disrupted, and the formation of metabolically active tetrahydrofolic acid from it, which is necessary for the formation of purines and pyrimidines, stops the growth and development of microorganisms (bacteriostatic effect).

Active against gram-positive and gram-negative cocci (including streptococci, pneumococci, meningococci, gonococci), Escherichia coli, Shigella spp. Chlamydia spp. , Actinomyces israelii, Toxoplasma gondii.

When applied topically, promotes rapid wound healing.

When taken orally, it is rapidly absorbed from the gastrointestinal tract. max”>C _max in the blood is created after 1–2 hours and decreases by 50%, usually in less than 8 hours. It passes through the histohematic, including the BBB, placental barriers. It is distributed in tissues, after 4 hours it is found in the cerebrospinal fluid. It is acetylated in the liver with loss of antibacterial properties. It is excreted mainly (90-95%) by the kidneys.

There is no information on carcinogenicity, mutagenicity and effects on fertility with long-term use in animals and humans.

Sulfanilamide used to be used orally to treat angina, erysipelas, cystitis, pyelitis, enterocolitis, prevention and treatment of wound infection. Sulfanilamide (Streptocid soluble) has been used in the past as 5% aqueous solutions for intravenous administration, which were prepared ex tempore ; currently used only in the form of liniment for external use.

Application of Sulfanilamide Sulfanilamide Sulfanilamide

local : tonsillitis, purulent-inflammatory lesions of the skin, infected wounds of various etiologies (including ulcers, cracks), furunculus, carbuncle, pyoderma, erysipelas, vulgar acne, impetigo, burns (I and II degrees).

Contraindications

Hypersensitivity (including to other sulfonamides and sulfonamides), diseases of the hematopoietic system, anemia, renal / hepatic insufficiency, congenital deficiency of glucose-6-phosphate dehydrogenase, azotemia, porphyria.

Restrictions for use

Pregnancy, lactation.

Use in pregnancy and lactation

Systemically absorbed sulfanilamide can rapidly cross the placenta and be detected in the blood of the fetus (the concentration in the blood of the fetus is 50-90% of that in the mother’s blood), as well as cause toxic effects. The safety of sulfanilamide during pregnancy has not been established. It is not known whether sulfonamide can cause fetal harm when taken by pregnant women. In experimental studies in rats and mice treated during pregnancy with certain short-, intermediate-, and long-acting oral sulfonamides (including sulfanilamide) at high doses (7–25 times the therapeutic oral dose for humans), a significant increase in the incidence of cleft palate and other fetal bone malformations.

Passes into breast milk, may cause kernicterus in neonates.

Adverse effects of the substance Sulfanilamide

Allergic reactions; with prolonged local use in large quantities – a systemic effect: headache, dizziness, paresthesia, tachycardia, nausea, vomiting, dyspepsia, leukopenia, agranulocytosis, crystalluria, cyanosis.

Interaction

Myelotoxic drugs increase hematotoxicity.

Dosage and administration

Local . With superficial infectious diseases of the skin and mucous membranes of the nasal cavity and ear, with burns, ulcers, etc. used in the form of 10% ointment, 5% liniment or powder. Liniment or ointment is applied directly to the affected surface or smeared on a gauze; dressings are made in 1-2 days. For deep wounds, sulfanilamide is introduced into the wound cavity in the form of a carefully ground sterilized powder (5–10–15 g), while sulfanilamide or other antibacterial drugs are administered orally. In a mixture with sulfathiazole, benzylpenicillin and ephedrine, it is sometimes used topically (for acute rhinitis) in powder form (by blowing or drawing it into the nose when inhaling).

Precautions

Periodic peripheral blood testing is necessary for long-term use.

Trade names with active ingredient Sulfanilamide

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All lek. forms liniment ointment for local and external use ointment for external use powder for external use substance substance-powder

Dosage
All dosages 10 g 10% 15 g 2 g 25 g 5 g 5% No dosage

Manufacturer
All manufacturers Avexima Siberia LLC Aromasintez LLC BioPharmCombinat LLC Biosintez OJSC Biosintez PJSC Zelenaya Dubrava CJSC Ivanovskaya Pharmaceutical Factory Irbit Chemical and Pharmaceutical Plant OJSC Lekar Lumi LLC [St. Petersburg] Meligen FP CJSC Moscow Pharmaceutical Factory NIZHFARM OAO Ozone LLC Samaramedprom Tver Pharmaceutical Factory OJSC Technopark -Center LLC Tula Pharmaceutical Factory LLC Tyumen Chemical-Pharmaceutical Plant Usolye-Sibirsky CPP JSC Usolye-Sibirsky CPP JSC Flora of the Caucasus JSC Flora of the Caucasus JSC Hubei Maxpharm Industries Co. Zhejiang Kemsen Pharm Co., Ltd. Empils-Foch JSC YuzhFarm LLC Yaroslavl Pharmaceutical Factory (ZAO YAFF)

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Sulfanilamide – description of the substance, pharmacology, use, contraindications, formula

Contents

• Structural formula

• Russian name

• English name

• Latin name

• chemical name

• Gross formula

• Pharmacological group of the substance Sulfanilamide

• Nosological classification

• CAS code

• pharmachologic effect

• Characteristic

• Pharmacology

• Application of the substance Sulfanilamide

• Contraindications

• Application restrictions

• Use during pregnancy and lactation

• Side effects of the substance Sulfanilamide

• Interaction

• Dosage and administration

• Precautionary measures

• Trade names with the active substance Sulfanilamide

Structural formula

Russian name

Sulfanilamide

English name

Sulfanilamide

Latin name

genus Sulfanilamidi)

Chemical name

4-Aminobenzenesulfonamide

General formula

C ₆ H ₈ N ₂ O ₂ S

Pharmacological group of the substance Sulfanilamide

Sulfonamides

Nosological classification

ICD-10 code list

CAS code

63-74-1

Pharmacological action

Pharmacological action 90 097-

antimicrobial .

Description

Refers to short-acting sulfa drugs. Sulfanilamide is a white, odorless, crystalline powder with a slightly bitter taste and a sweet aftertaste. Easily soluble in boiling water (1:2), difficult – in ethanol (1:37), soluble in solutions of hydrochloric acid, caustic alkalis, acetone (1:5), glycerin, propylene glycol; practically insoluble in ether, chloroform, benzene, petroleum ether. Molecular weight – 172.21.

Also used as sodium methane sulfate (Streptocide soluble) – white crystalline powder; soluble in water, practically insoluble in organic solvents.

Pharmacology

The mechanism of antimicrobial action of sulfanilamide is associated with the antagonism of PABA, with which it has a chemical similarity. Sulfanilamide is captured by the microbial cell, prevents the incorporation of PABA into dihydrofolic acid and, in addition, competitively inhibits the bacterial enzyme dihydropteroate synthetase (the enzyme responsible for the incorporation of PABA into dihydrofolic acid), as a result, the synthesis of dihydrofolic acid is disrupted, and the formation of metabolically active tetrahydrofolic acid from it, which is necessary for the formation of purines and pyrimidines, stops the growth and development of microorganisms (bacteriostatic effect).

Active against gram-positive and gram-negative cocci (including streptococci, pneumococci, meningococci, gonococci), Escherichia coli, Shigella spp. Chlamydia spp. , Actinomyces israelii, Toxoplasma gondii.

When applied topically, promotes rapid wound healing.

When taken orally, it is rapidly absorbed from the gastrointestinal tract. max”>C _max in the blood is created after 1–2 hours and decreases by 50%, usually in less than 8 hours. It passes through the histohematic, including the BBB, placental barriers. It is distributed in tissues, after 4 hours it is found in the cerebrospinal fluid. It is acetylated in the liver with loss of antibacterial properties. It is excreted mainly (90-95%) by the kidneys.

There is no information on carcinogenicity, mutagenicity and effects on fertility with long-term use in animals and humans.

Sulfanilamide used to be used orally to treat angina, erysipelas, cystitis, pyelitis, enterocolitis, prevention and treatment of wound infection. Sulfanilamide (Streptocid soluble) has been used in the past as 5% aqueous solutions for intravenous administration, which were prepared ex tempore ; currently used only in the form of liniment for external use.

Application of Sulfanilamide Sulfanilamide Sulfanilamide

local : tonsillitis, purulent-inflammatory lesions of the skin, infected wounds of various etiologies (including ulcers, cracks), furunculus, carbuncle, pyoderma, erysipelas, vulgar acne, impetigo, burns (I and II degrees).

Contraindications

Hypersensitivity (including to other sulfonamides and sulfonamides), diseases of the hematopoietic system, anemia, renal / hepatic insufficiency, congenital deficiency of glucose-6-phosphate dehydrogenase, azotemia, porphyria.

Restrictions for use

Pregnancy, lactation.

Use in pregnancy and lactation

Systemically absorbed sulfanilamide can rapidly cross the placenta and be detected in the blood of the fetus (the concentration in the blood of the fetus is 50-90% of that in the mother’s blood), as well as cause toxic effects. The safety of sulfanilamide during pregnancy has not been established. It is not known whether sulfonamide can cause fetal harm when taken by pregnant women. In experimental studies in rats and mice treated during pregnancy with certain short-, intermediate-, and long-acting oral sulfonamides (including sulfanilamide) at high doses (7–25 times the therapeutic oral dose for humans), a significant increase in the incidence of cleft palate and other fetal bone malformations.

Passes into breast milk, may cause kernicterus in neonates.

Adverse effects of the substance Sulfanilamide

Allergic reactions; with prolonged local use in large quantities – a systemic effect: headache, dizziness, paresthesia, tachycardia, nausea, vomiting, dyspepsia, leukopenia, agranulocytosis, crystalluria, cyanosis.

Interaction

Myelotoxic drugs increase hematotoxicity.

Dosage and administration

Local . With superficial infectious diseases of the skin and mucous membranes of the nasal cavity and ear, with burns, ulcers, etc. used in the form of 10% ointment, 5% liniment or powder. Liniment or ointment is applied directly to the affected surface or smeared on a gauze; dressings are made in 1-2 days. For deep wounds, sulfanilamide is introduced into the wound cavity in the form of a carefully ground sterilized powder (5–10–15 g), while sulfanilamide or other antibacterial drugs are administered orally. In a mixture with sulfathiazole, benzylpenicillin and ephedrine, it is sometimes used topically (for acute rhinitis) in powder form (by blowing or drawing it into the nose when inhaling).

Precautions

Periodic peripheral blood testing is necessary for long-term use.

Trade names with active ingredient Sulfanilamide

Reset filters

Lek. form
All lek. forms liniment ointment for local and external use ointment for external use powder for external use substance substance-powder

Dosage
All dosages 10 g 10% 15 g 2 g 25 g 5 g 5% No dosage

Manufacturer
All manufacturers Avexima Siberia LLC Aromasintez LLC BioPharmCombinat LLC Biosintez OJSC Biosintez PJSC Zelenaya Dubrava CJSC Ivanovskaya Pharmaceutical Factory Irbit Chemical and Pharmaceutical Plant OJSC Lekar Lumi LLC [St.