OXYMET 5% WSP

Indications

• Acne vulgaris
• Chlamydia infections
• Respiratory tract infections
• Urinary tract infections
• Skin and soft tissue infections
• Periodontal disease

Dosage

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

Adults: Refer to the BNF for specific adult dosing.

Mechanism of action

Oxytetracycline works by binding to the 30S ribosomal subunit of bacteria, preventing the attachment of aminoacyl-tRNA to the ribosomal acceptor site. This action inhibits protein synthesis, leading to the cessation of bacterial growth. The drug is also known to have some anti-inflammatory properties.

Pharmacodynamics

The pharmacodynamics of oxytetracycline is characterized by its ability to inhibit the growth of susceptible bacteria, leading to a bacteriostatic effect. The spectrum of activity includes a variety of organisms, including some strains of Streptococcus, Staphylococcus, and Escherichia coli. The drug also displays activity against certain protozoa. Resistance can occur through various mechanisms, including efflux pumps and ribosomal protection.

Pharmacokinetics

Oxytetracycline is well-absorbed from the gastrointestinal tract, although its absorption can be reduced by the presence of divalent and trivalent metal ions such as calcium and magnesium. The drug is widely distributed in body tissues and fluids, including the liver, kidneys, and lungs. It is metabolized primarily in the liver and excreted mainly in the urine. Its half-life is approximately 6 to 12 hours, depending on the formulation and patient factors.

Contra-indications

• Hypersensitivity to oxytetracycline or any tetracycline antibiotics
• Pregnancy, particularly during the second and third trimesters
• Severe liver impairment
• Children under 8 years due to the risk of permanent tooth discoloration

Adverse effects

• Gastrointestinal disturbances such as nausea, vomiting, and diarrhea
• Photosensitivity reactions
• Esophageal irritation or ulceration
• Superinfection with non-susceptible organisms, including fungi
• Hepatotoxicity, particularly in patients with pre-existing liver disease
• Renal toxicity, especially with high doses or prolonged use

Interactions

• Antacids containing aluminum, calcium, or magnesium can reduce the absorption of oxytetracycline
• Iron supplements and multivitamins containing iron may also decrease the effectiveness of oxytetracycline
• Oral contraceptives may be less effective when taken with oxytetracycline
• Warfarin effects may be enhanced due to changes in gut flora

Precautions

• Use cautiously in patients with liver or renal impairment
• Monitor for signs of superinfection
• Avoid use in children under 8 years to prevent dental discoloration
• Consider alternative antibiotics if the patient has a history of hypersensitivity to tetracyclines

Pregnancy

Oxytetracycline should not be used during pregnancy, especially in the second and third trimesters, due to the risk of fetal harm, including impaired bone growth and discoloration of teeth.

Breast-feeding

Oxytetracycline is excreted in breast milk; caution is advised as it may affect the infant's gut flora and bone development.

Storage

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

Formulations

• Oral tablets
• Oral suspension
• Topical ointment
• Injection