Author: Rimsha Nazir
INTRODUCTION
When it comes to combating bacterial infections, Sulfonamide medications have been essential in contemporary medicine. Commonly known as “SULFA DRUGS”, these antibiotics have been saving lives since they were created in the 1930s. But what precisely are sulfonamides, how do they function, and why do they continue to be important today? Let’s delve into the intriguing realm of sulfonamide medications and examine their applications, mechanisms, and influence on healthcare.
SULFONAMIDE DRUGS
A group of synthetic medications known as Sulfonamides contains the sulfonamide chemical group. Sulfonamides are known as “SULFA DRUGS”.
- Sulfonamides are antimicrobial substances that can stop some pathogenic bacteria from growing.
- The first effectively synthesized selectively harmful antibacterial medicines are sulfonamides.
- Sulfonamides are significant in medicinal chemistry because it exhibits a variety of biological properties including antibacterial, hypoglycemic, diuretic, anti-inflammatory, anti-cancer, and anti-hypertensive qualities with potential use in agriculture.
- Gerhard Domagk received Noble Prize in medicine for his contributions to the discovery of Sulfonamide drug.
STRUCTURE
The basic structure of sulfonamide contains
- Sulfonamide group (SO2-NH2)
- Free amino group.
Basic Structure of Sulfonamide
The basic structure of sulfonamides includes the amino group and the sulfonamide group in the para position of the benzene ring. A considerable number of sulfonamide derivatives are produced by replacing the nitrogen of the sulfonamide group (N1) with a hydrogen atom. Still, only a small number of active sulfonamide medicines were made by replacing the nitrogen of the aromatic amino group (N4) with a hydrogen atom.
CLASSIFICATION OF SULFONAMIDES
The sulfonamides are divided into the following classes to support this.
1. SHORT ACTING SULFONAMIDES
- Short-acting sulfonamides have a half-life of fewer than 10 hours.
- These are used to treat infections of the urinary tract.
- These include Sulfamethizole, Sulfisoxazole, and Sulfanilamide.
2. INTERMEDIATE ACTING SULFONAMIDES
- Intermediate-acting sulfonamides have a half-life of 10 to 24 hours.
- These are particularly effective against invasive aspergillosis in AIDS patients.
- These include Sulfamethoxazole, sulfacetamide, and sulfadiazine.
3. LONG-ACTING SULFONAMIDES
- Long-acting sulfonamides have a half-life of more than 24 hours.
- These are used to treat ulcerative colitis.
- These include Sulfadimethoxine, and Sulfadoxine.
4. SPECIAL PURPOSE SULFONAMIDES
- These include Sulfacetamide sodium, Silver sulfadiazine, Sulfasalazine, and mafenide.
MECHANISM OF ACTION OF SULFONAMIDE DRUGS
Sulfonamides inhibit multiplication of bacteria by acting as competitive inhibitors of p-aminobenzoic acid (PABA) in the folic acid metabolism cycle. Because sulfonamides structurally resemble to p-aminobenzoic acid (PABA).
RESISTANCE TO SULFONAMIDE DRUGS
Sulfonamide drugs are effective against both Gram-positive and Gram-negative bacterial infections. Most bacteria, including, Gonococci, Pneumococci etc. are capable of developing sulfonamide resistance. Resistance to sulfonamides is caused by reduced drug permeability, an increase in bacterial PABA or Dihydropteroate synthase, or the creation of changed enzyme that has no impact on the medication. Bacterial cells are rarely resistant because they can absorb folate. Sulfonamides inhibit the bacterial enzyme Dihydropteroate synthase (DHPS), thus blocking synthesis of nucleic acid as well as the biosynthesis of folic acid. This Bacteriostatic action inhibits the growth of various Gram-positive and Gram-negative bacteria.
THERAPEUTIC USES OF SULFONAMIDES
Sulfonamides are widely used in the prevention and treatment of local and systemic infections in all species.
- Sulfadoxine in combination with pyrimethamine is used as an anti-malarial drug.
- Sulfacetamide is used in the treatment of acne and to treat conjunctivitis.
- Sulfadiazine is an antibacterial medicine that is used in a topical burn treatment as a 1% w/w oil-water cream.
- To avoid the spread of disease in freshwater aquaculture, Sulfadimethoxine, as an antibiotic, is combined with ormetoprim.
- Sulfamethoxazole is used to treat infections like middle ear infections, CNS infections, Nocardia infections.
- Sulfamethoxazole is also used to treat the respiratory infections and to treat ear infections in children.
- Sulfanilamide is used to treat beta-hemolytic streptococcal infections. It is an effective chemotherapeutic agent.
- Sulfamethizole is the only drug available in conventional dosage form and is primarily used orally to treat urinary tract infections.
- Sulfacetamide is used in ophthalmic preparations.
- The wound healing efficacy increases by using a 5% mafenide acetate solution.
SIDE EFFECTS OF SULFONAMIDE DRUGS
Sulphonamide have been linked to a number of side effects such as;
- Nausea
- Hematopoietic disorder
- Porphyria
- Hypersensitivity reaction
- Urinary tract disorder
- Skin rash
- Tiredness
- Dizziness
- Diarrhea
- Stevenson’s Johnson syndrome (SJS)
- Drug Reaction with Eosinophilia and Systemic Syndrome (DRESS)
- Pulmonary eosinophilia
- Toxic epidermal necrolysis.
CONCLUSION
It has been decades since sulfonamide drugs have been used in the treatment of bacterial infections. The inhibition of folate synthesis broadens their efficacy against many pathogens. Despite the resistance seen with certain bacteria, sulfonamides remain useful in conjunction with other therapies and are employed even beyond infections, in dermatology and ophthalmology. Sulfonamides must, however, continue to be part and parcel of modern medicine through their sensible use.
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