Overview
Spiramycin is a macrolide antibiotic derived from Streptomyces ambofaciens, used primarily for treating various bacterial infections. It exhibits bacteriostatic activity by inhibiting protein synthesis through binding to the 50S ribosomal subunit. Spiramycin has good tissue penetration and is particularly noted for its use in toxoplasmosis during pregnancy.
Mechanism of Action
Binds reversibly to the 50S subunit of bacterial ribosomes, inhibiting translocation during protein synthesis. This bacteriostatic action prevents bacterial growth without directly killing the organism.
Indications
- Toxoplasmosis (especially during pregnancy)
- Respiratory tract infections
- Skin and soft tissue infections
- Dental infections
- Prevention of meningococcal meningitis in contacts
Dosage
Adults: 2-3 grams daily in divided doses (typically 1.5 million IU twice daily or 1 million IU three times daily). Duration varies by indication: 10-14 days for most infections, 3 weeks for toxoplasmosis during pregnancy. Pediatric dosing based on weight.
Contraindications
- Hypersensitivity to spiramycin or other macrolides
- Severe hepatic impairment
- Concomitant use with ergot derivatives
Side Effects
- Gastrointestinal disturbances (nausea, vomiting, diarrhea)
- Allergic reactions (rash, urticaria)
- QT interval prolongation
- Hepatotoxicity (elevated liver enzymes)
- Taste disturbances
Interactions
- Ergot alkaloids (increased risk of ergotism)
- Cyclosporine (increased cyclosporine levels)
- Theophylline (possible increased theophylline levels)
- Oral contraceptives (potential decreased efficacy)