METRICYCLIN OBLETS

Indications

• Bacterial infections
• Respiratory tract infections
• Urinary tract infections
• Acne
• Chlamydia infections
• Mycoplasma pneumonia

Dosage

Children: Refer to the BNF for Children for specific dosing information.

Adults: Refer to the BNF for specific dosing information.

Mechanism of action

Chlortetracycline exerts its antibacterial effect by binding to the 30S ribosomal subunit of bacteria, inhibiting protein synthesis. This action prevents the addition of amino acids to the growing polypeptide chain, ultimately leading to cell death in susceptible organisms. It is effective against a variety of organisms, including both aerobic and anaerobic bacteria.

Pharmacodynamics

The pharmacodynamics of chlortetracycline involves its ability to inhibit bacterial protein synthesis, which is crucial for bacterial growth and reproduction. The drug's effectiveness is dependent on the concentration of the drug at the site of infection and the susceptibility of the bacteria. Bacteriostatic in nature, chlortetracycline stops bacteria from multiplying rather than killing them outright.

Pharmacokinetics

Chlortetracycline is well absorbed from the gastrointestinal tract, with peak plasma concentrations occurring within 1 to 2 hours after oral administration. It is widely distributed throughout the body, including into tissues and body fluids. The drug can be excreted in urine, and its half-life varies from 6 to 12 hours, depending on the individual’s renal function. Biliary excretion also occurs.

Contra-indications

• Hypersensitivity to chlortetracycline or any component of the formulation
• Porphyria
• Renal impairment

Adverse effects

• Gastrointestinal disturbances (nausea, vomiting, diarrhea)
• Photosensitivity
• Skin rashes
• Esophageal irritation
• Hepatotoxicity
• Superinfection (due to prolonged use)

Interactions

• Antacids containing aluminum, calcium, or magnesium may reduce absorption of chlortetracycline
• Iron supplements can interfere with absorption
• Oral contraceptives may have reduced efficacy when taken with chlortetracycline
• Warfarin may have increased anticoagulant effect

Precautions

• Use with caution in patients with liver or renal impairment
• Monitor for signs of superinfection
• Avoid prolonged exposure to sunlight or UV light
• Consider potential effects on developing teeth in children

Pregnancy

Chlortetracycline is generally not recommended during pregnancy due to potential harm to the developing fetus, particularly effects on tooth development.

Breast-feeding

Chlortetracycline is excreted in breast milk and may affect the infant; use with caution.

Storage

Store in a cool, dry place away from light. Keep out of reach of children.

Formulations

• Oral tablets
• Topical ointments
• Liquid formulations