Chlortetracycline is a broad-spectrum antibiotic and the first member of the tetracycline group, discovered in 1945 by Benjamin Duggar from the bacterium Streptomyces aureofaciens and initially marketed as Aureomycin; it acts by inhibiting bacterial protein synthesis, making it bacteriostatic, and is effective against a wide range of Gram-positive and Gram-negative bacteria as well as organisms like rickettsiae and chlamydiae, with applications in treating infections in humans and, more commonly today, in veterinary medicine, while also paving the way for related antibiotics such as Tetracycline and Doxycycline.
BRAND NAMES
Aureomycin : Chlortetracycline is a tetracycline antibiotic mainly used in topical and ophthalmic (eye) preparations for treating bacterial infections by inhibiting bacterial protein synthesis. It is commonly known by the brand name Aureomycin and is available in ointments for skin and eye infections.
MECHANISM OF ACTION
Chlortetracycline (a tetracycline antibiotic) works by inhibiting bacterial protein synthesis. It binds reversibly to the 30S ribosomal subunit of bacteria, preventing the attachment of aminoacyl-tRNA to the mRNA–ribosome complex, which blocks the addition of new amino acids to the growing peptide chain and stops bacterial growth (bacteriostatic effect).
PHARMACODYNAMICS
Chlortetracycline is a bacteriostatic antibiotic that inhibits bacterial protein synthesis by reversibly binding to the 30S ribosomal subunit, preventing aminoacyl-tRNA attachment and blocking peptide chain formation, thereby stopping bacterial growth.
ADMINISTRATION
It is mainly administered topically as eye ointments or skin ointments for local bacterial infections; systemic use is now rare.
DOSAGE AND STRENGTH
Common ophthalmic/dermal ointments are typically available in 0.5%–1% strength, applied 2–4 times daily depending on infection severity and medical advice.
DRUG INTERACTIONS
May reduce effectiveness when used with bactericidal antibiotics; interaction possible with antacids, calcium, iron, or magnesium-containing products due to reduced absorption (more relevant in systemic use).
FOOD INTERACTIONS
Dairy products and calcium-rich foods can reduce absorption in systemic therapy, but food interactions are minimal in topical use.
CONTRAINDICATIONS
Contraindicated in patients with known hypersensitivity to tetracyclines and generally avoided in pregnant women and children under 8 years (for systemic exposure).
SIDE EFFECTS
May include local irritation, redness, burning sensation, itching, and rarely allergic reactions.
OVERDOSE
Overdose is rare with topical use; excessive application may cause increased local irritation or hypersensitivity reactions.
TOXICITY
Systemic toxicity is uncommon due to limited absorption in topical use, but tetracyclines in general may cause liver toxicity, photosensitivity, and effects on bone and teeth development when used systemically.
