What is the recommended dose and frequency of doxycycline (antibiotic) for treating infections?

Recommended Doxycycline Dosing for Treating Infections

The standard recommended dose of doxycycline for treating most bacterial infections in adults is 100 mg twice daily (every 12 hours), with an initial loading dose of 200 mg on the first day of treatment. 1

Adult Dosing Regimens

Standard Treatment for Common Infections

• Initial dose: 200 mg on day 1 (administered as 100 mg every 12 hours) 1
• Maintenance dose: 100 mg once daily or 100 mg every 12 hours for more severe infections 1
• Duration: Typically 7-14 days depending on the type and severity of infection 2

Specific Infection Types and Durations

• Skin and soft tissue infections: 100 mg twice daily for 7-14 days 2
• Respiratory tract infections: 100 mg twice daily for 7-21 days 2, 3
• Urinary tract infections (severe/chronic): 100 mg every 12 hours 1
• Sexually transmitted infections:
  • Uncomplicated chlamydial infections: 100 mg twice daily for 7 days 1
  • Nongonococcal urethritis: 100 mg twice daily for 7 days 1
  • Uncomplicated gonococcal infections: 100 mg twice daily for 7 days (or alternative single visit dose of 300 mg followed by another 300 mg one hour later) 1

Pediatric Dosing (for children over 8 years of age)

• Initial dose: 2 mg/lb (4.4 mg/kg) of body weight divided into two doses on day 1 1
• Maintenance dose: 1 mg/lb (2.2 mg/kg) of body weight daily as a single dose or divided into two doses 1
• For severe infections: Up to 2 mg/lb (4.4 mg/kg) of body weight may be used 1
• For children over 100 lbs: Use standard adult dosing 1
• Note: Doxycycline is not recommended for children under 8 years of age 2

Special Considerations

Administration Guidelines

• Take with adequate amounts of fluid to reduce the risk of esophageal irritation 1
• If gastric irritation occurs, take with food or milk 1
• Patient should remain upright for at least 1 hour after taking doxycycline to prevent esophagitis 2
• The absorption of doxycycline is not markedly influenced by simultaneous ingestion of food or milk 1

Renal Impairment

• No dosage adjustment is necessary in patients with renal impairment 1, 4
• Doxycycline does not accumulate in patients with renal insufficiency 4

Common Side Effects

• Gastrointestinal effects (nausea, vomiting, diarrhea) 1, 5
• Photosensitivity 2
• Esophagitis and esophageal discomfort 2

Treatment Duration by Infection Type

• Streptococcal infections: Continue therapy for 10 days 1
• Skin and soft tissue infections: 5-10 days for uncomplicated cases 2
• Community-acquired pneumonia: 7-14 days 3
• Sexually transmitted infections: 7-10 days depending on the pathogen 1

Pitfalls and Caveats

• Exceeding the recommended dosage may result in increased side effects 1
• Doxycycline is contraindicated in children under 8 years of age due to the risk of dental staining 2
• For severe infections requiring long-term therapy, monitor for superinfection, especially with non-susceptible organisms 2
• Photosensitivity reactions can be severe; patients should be advised to avoid direct sunlight and use sun protection 2

Doxycycline's excellent tissue penetration, broad-spectrum activity, and once or twice daily dosing make it an effective and convenient option for treating a wide range of bacterial infections 4.