Dosage and Usage of Apo-Tetra (Tetracycline) for Bacterial Infections
For adults, the standard dosage of tetracycline is 1 gram daily, administered as either 500 mg twice daily or 250 mg four times daily. Higher doses of 500 mg four times daily may be required for severe infections or those not responding to lower doses. 1
Adult Dosing Guidelines
- Standard adult dosage: 1 gram daily, given as either:
- 500 mg twice daily, or
- 250 mg four times daily 1
- For severe infections: 500 mg four times daily 1
- Duration of therapy is typically 7 days, depending on clinical response 2
Specific Infection Dosing
- For streptococcal infections: Continue therapy for 10 days 1
- For brucellosis: 500 mg four times daily for three weeks (accompanied by streptomycin) 1
- For syphilis in penicillin-allergic patients:
- Early syphilis (less than one year): 500 mg four times daily for 15 days
- Late syphilis (more than one year): 500 mg four times daily for 30 days 1
- For gonorrhea: 500 mg four times daily for seven days 1
- For Chlamydia trachomatis infections: 500 mg four times daily for at least seven days 1
- For acne: Initial dosage of 1 gram daily in divided doses, with gradual reduction to maintenance levels of 125-500 mg daily when improvement occurs 1
Pediatric Dosing
- For children above 8 years of age: 10-20 mg/lb (25-50 mg/kg) body weight daily, divided into four equal doses 1
- Important: Tetracyclines should not be used in children under 8 years of age due to risk of tooth enamel discoloration 2, 3
Administration Guidelines
- Take with adequate amounts of fluid to reduce risk of esophageal irritation and ulceration 1
- Absorption is impaired by:
- Antacids containing aluminum, calcium, or magnesium
- Preparations containing iron, zinc, or sodium bicarbonate
- Food and some dairy products 1
Special Populations
- Renal impairment: Decrease total dosage by reducing individual doses and/or extending time intervals between doses 1
- Pregnancy: Tetracyclines are not recommended during pregnancy 2
Common Side Effects and Precautions
- Gastrointestinal irritation and diarrhea 4
- Phototoxic dermatitis 4
- Yeast superinfection 3
- Vestibular damage (particularly with minocycline) 3, 4
Clinical Considerations
- Tetracyclines are bacteriostatic and act by binding to the bacterial 30S ribosomal subunit to inhibit protein synthesis 5
- Doxycycline is often preferred over tetracycline for most indications due to its twice-daily dosing, better absorption with food, and no requirement for dose adjustment in renal insufficiency 6
- Resistance to tetracyclines has increased over time, limiting their use for some infections 5
- Tetracyclines have broad-spectrum activity against gram-positive and gram-negative bacteria, as well as atypical organisms 5
Remember that while tetracyclines have a broad spectrum of activity, local resistance patterns should be considered when selecting antimicrobial therapy, and susceptibility testing should guide treatment decisions when possible 2.