Effect
- Antibacterial
- Bakeriostatic
- Antiparasitic against protozoa
Mechanism of action
Sulfonamides inhibit the synthesis of folic acid in microorganisms. They are structural analogues (antimetabolites) of the natural substrate p-aminobenzoic acid and competitively displace it. Trimethoprim, used in combination with sulfamethoxazole, has a synergistic effect.
Indications
Bacterial infectious diseases caused by:
- Streptococcus
- Pneumococcus
- Actinomycetes
- Nocardia, e.g. nocaridosis
- Chlamydia, e.g. trachoma
Some infections caused by protozoa:
- Pneumocystitis carinii, e.g. Pneumocystitis carinii pneumonia (sulfamethoxazole + trimethoprim).
- , toxoplasmosis (sulfadiazine + pyrimethamine).
- Plasmodia
External:
- Silver sulfadiazine (Flammazine): infection prophylaxis, therapy of skin and wound infections and burns.
- Sulfacetamide (Blephamide): superficial sulfacetamide-sensitive eye infections, e.g., conjunctivitis. In the U.S.: rosacea, acne.
Locally in the intestine:
- Inflammatory diseases in the colon
Structure and structure example
Active ingredients
External:
- Silver sulfadiazine (Flammazine).
- Sulfacetamide + prednisolone (Blephamide).
Internal:
- Sulfadiazine
- Trimethoprim and sulfamethoxazole = cotrimoxazole (Bactrim, generics).
- Sulfadoxine + pyrimethamine (Fansidar, off label).
Effective locally in the intestine:
- Sulfasalazine (salazopyrin).
Adverse effects
- Gastrointestinal discomfort
- Blood count changes
- Allergic skin reactions
- Photosensitization
- Headache
- Joint pain
- Hypoglycemia
Advice notes
- Regularly check the blood count
- Adequate fluid intake to reduce the risk of crystalluria
- Exposure to strong sunlight and UV light may cause photosensitization
