Renamycin

Approved Indications:

• Bacterial infections caused by susceptible organisms, including:
• Respiratory tract infections (e.g., bronchitis, pneumonia)
• Urinary tract infections (UTIs)
• Skin and soft tissue infections (e.g., acne vulgaris, infected wounds)
• Eye infections (e.g., conjunctivitis, blepharitis – topical form)
• Gastrointestinal infections (e.g., cholera)
• Rickettsial infections (e.g., typhus, Rocky Mountain spotted fever)
• Brucellosis (with aminoglycoside)
• Chlamydial infections (e.g., trachoma, psittacosis)
• Mycoplasma pneumonia
• Plague, tularemia, and anthrax (alternative treatment)

Off-label or Less Common Uses:

• Acne rosacea (topical form)
• Malaria prophylaxis (where appropriate)
• Periodontal infections (in veterinary and some human applications)

Adults (Oral):

• General infections: 250–500 mg every 6 hours (1–2 g/day in divided doses)
• Acne vulgaris: 250 mg twice daily for several weeks or months
• Chlamydia/RTI: 500 mg every 6 hours for 7–14 days

Children (>8 years):

• 25–50 mg/kg/day in 4 divided doses
• Not recommended for children <8 years due to risk of permanent teeth discoloration

Eye Ointment:

• Apply 1 cm ribbon to affected eye(s) every 2–4 hours initially, then less frequently as symptoms improve

Topical cream:

• Apply a thin layer to affected skin area 1–3 times daily

Special Populations:

• Renal impairment: Use cautiously; accumulation may occur
• Hepatic impairment: Monitor closely; adjust dose if liver dysfunction is present
• Elderly: Standard adult dose, with renal and hepatic monitoring

Administration Notes:

• Oral forms should be taken on an empty stomach (1 hour before or 2 hours after meals) with plenty of water
• Avoid taking with dairy products, antacids, or iron supplements (reduces absorption)

Oxytetracycline is a broad-spectrum bacteriostatic antibiotic that inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit of susceptible organisms. This blocks the attachment of aminoacyl-tRNA to the mRNA-ribosome complex, preventing the addition of new amino acids to the growing peptide chain. The result is inhibition of bacterial growth and replication. It is active against a wide range of gram-positive and gram-negative bacteria, rickettsiae, chlamydiae, and mycoplasmas.

• Absorption: Well absorbed orally, though reduced by food, antacids, and iron; ~60–80% bioavailability
• Distribution: Widely distributed in body tissues and fluids; crosses placenta; enters breast milk
• Protein Binding: ~20–40%
• Metabolism: Minimal hepatic metabolism
• Half-life: 6–12 hours (varies by dose and formulation)
• Excretion: Primarily renal (glomerular filtration); some biliary excretion

• Pregnancy: Category D. Contraindicated during the second and third trimesters due to risk of fetal tooth discoloration and bone growth inhibition.
• Lactation: Excreted into breast milk; may cause dental staining and bone growth suppression in the nursing infant. Not recommended during breastfeeding.

• Tetracycline antibiotic
• Bacteriostatic antimicrobial agent

• Known hypersensitivity to tetracyclines
• Severe hepatic or renal impairment (use with caution or avoid)
• Children <8 years of age (risk of permanent teeth discoloration and enamel hypoplasia)
• Pregnancy and breastfeeding (due to teratogenic and toxic effects)

• Photosensitivity: Patients should avoid excessive sunlight or UV exposure
• Tooth discoloration: Avoid use in children under 8 years and during pregnancy
• Superinfections: May result from prolonged use (e.g., fungal overgrowth, pseudomembranous colitis)
• Hepatic toxicity: Use with caution in liver dysfunction or with hepatotoxic drugs
• Renal toxicity: Accumulation may occur in renal impairment
• Intracranial hypertension: Rare but serious; monitor for signs (e.g., headache, vision changes)
• Diarrhea: Persistent or severe diarrhea may indicate Clostridioides difficile colitis

Common:

• Gastrointestinal: Nausea, vomiting, epigastric distress, diarrhea
• Skin: Photosensitivity, rash
• Oral: Glossitis, stomatitis, tooth discoloration

Less Common:

• CNS: Headache, dizziness
• Liver: Elevated liver enzymes, hepatic toxicity
• Blood: Anemia, leukopenia (rare)

Rare but Serious:

• Pseudomembranous colitis
• Intracranial hypertension
• Anaphylaxis or severe allergic reactions

• Antacids/calcium/magnesium/iron supplements: Reduce absorption of oxytetracycline
• Oral contraceptives: May reduce efficacy; recommend backup contraception
• Warfarin: Potentiation of anticoagulant effects
• Penicillin antibiotics: May antagonize bactericidal effect
• Retinoids (e.g., isotretinoin): Increased risk of intracranial hypertension

• Many global guidelines (e.g., WHO, CDC) now recommend limited tetracycline use due to growing bacterial resistance
• Still retained as an option for rickettsial infections, brucellosis, and certain resistant cases where alternatives are not available
• Continued warnings regarding pediatric use and pregnancy-related risks

• Store below 25°C in a dry place
• Protect from light and moisture
• Keep tightly closed in original container
• Do not use expired medication (risk of nephrotoxicity with degraded tetracyclines)
• Reconstituted oral suspension should be used within the prescribed period (typically 7–14 days)