API Sulfamethazine

Sulfamethazine More Info

Sulfamethazine is a synthetic sulfonamide antimicrobial agent that belongs to the class of sulfanilamide derivatives, widely used in veterinary medicine and occasionally in human clinical practice for specific indications.

Basic Chemical Properties

Chemical Formula: C₁₂H₁₄N₄O₂S

Molecular Weight: 278.33 g/mol

Appearance: It typically exists as a white or off-white crystalline powder with slight solubility in water, but increased solubility in dilute acids or alkaline solutions.

CAS Number: 57-68-1

Mechanism of Action

Sulfamethazine exerts its antibacterial effect by competing with para-aminobenzoic acid (PABA) for the active site of the enzyme dihydropteroate synthase in bacteria. This enzyme is essential for the synthesis of folic acid, a key nutrient required for bacterial DNA replication and cell growth. By inhibiting folic acid synthesis, sulfamethazine suppresses the proliferation of susceptible bacteria. It is primarily effective against gram-positive bacteria (e.g., Streptococcus spp., Staphylococcus spp.) and some gram-negative bacteria (e.g., Escherichia coli, Klebsiella spp.), but it is inactive against viruses, fungi, or anaerobic bacteria.

Applications

Veterinary Medicine (Primary Use)It is commonly used to prevent and treat bacterial infections in livestock (cattle, swine, poultry) and companion animals. Indications include respiratory tract infections, urinary tract infections, enteritis, and systemic infections caused by susceptible pathogens. It can be administered via oral, injectable, or feed-mixed routes, with strict adherence to dosage guidelines to avoid residue accumulation in animal products.

Human Medicine (Limited Use)Due to the emergence of sulfonamide-resistant bacteria and the availability of more effective antibiotics, its use in humans is restricted. It may be prescribed for treating uncomplicated urinary tract infections or as a second-line agent for certain protozoal infections (e.g., toxoplasmosis) in combination with other drugs.

Safety and Precautions

Allergic Reactions: Sulfamethazine can trigger hypersensitivity reactions in some individuals, ranging from mild skin rashes to severe conditions like Stevens-Johnson syndrome. Patients with a history of sulfonamide allergy should avoid this drug.

Residue and Resistance Risks: Overuse or improper administration in animals can lead to antibiotic residues in meat, milk, and eggs, posing potential health risks to humans. Long-term use also contributes to the development of bacterial resistance.

Side Effects: In humans, common side effects include gastrointestinal disturbances (nausea, vomiting), hematological abnormalities (anemia, leukopenia), and renal toxicity. Close monitoring of blood and urine parameters is recommended during treatment.

Drug Interactions: It may interact with anticoagulants, hypoglycemic agents, or methotrexate, enhancing their pharmacological effects and increasing the risk of adverse reactions.

Regulatory Status

In most countries, sulfamethazine is classified as a prescription drug in both human and veterinary medicine. Strict regulations govern its use in food-producing animals, including maximum residue limits (MRLs) and withdrawal periods to ensure food safety.