What is the recommended dosage of doxycycline (tetracycline antibiotic) for treating wound infections?

Doxycycline Dosage for Wound Infections

For wound infections, doxycycline 100 mg twice daily is the recommended dosage for adults, with treatment duration typically 7-14 days depending on infection severity and clinical response. 1, 2

Standard Dosing Regimen

Adults

• Initial dose: 200 mg on day 1 (administered as 100 mg every 12 hours) 2
• Maintenance dose: 100 mg twice daily (every 12 hours) 1, 2
• Duration: 7-14 days for most bacterial skin and soft tissue infections 1

Pediatric Patients (>8 years of age)

• Children ≤100 lbs: 2 mg/lb divided into two doses on day 1, then 1 mg/lb daily (as single or divided dose) 2
• Children >100 lbs: Use adult dosing 2
• For severe infections: Up to 2 mg/lb may be used 2

Clinical Context and Coverage

Doxycycline provides good activity against Eikenella species, staphylococci, and anaerobes, though some streptococci may be resistant. 1 Importantly, doxycycline misses MRSA coverage, which is a critical limitation for empiric wound infection treatment. 1

When Doxycycline is Appropriate:

• Mild cases of specific infections including tularemia, bubonic plague, and bacillary angiomatosis 1
• Animal bite wounds (though amoxicillin-clavulanate is preferred as first-line) 1
• Specific pathogens like Aeromonas hydrophila or Vibrio vulnificus (combined with ciprofloxacin or ceftriaxone) 1

When Doxycycline is NOT Appropriate:

• Severe necrotizing infections requiring broad-spectrum coverage with vancomycin plus piperacillin-tazobactam or carbapenems 1
• Suspected MRSA infections where vancomycin or other anti-MRSA agents are needed 1
• Meningitis concerns due to poor CNS penetration 1

Important Clinical Considerations

Administration Guidelines

• Give with adequate fluids to reduce risk of esophageal irritation and ulceration 2
• May be given with food or milk if gastric irritation occurs, as absorption is not significantly affected 2
• No dose adjustment needed for renal impairment at usual recommended doses 2

Duration Adjustments

• Preemptive therapy for high-risk bite wounds: 3-5 days for immunocompromised patients, asplenic patients, those with advanced liver disease, or moderate-to-severe injuries 1
• Extended therapy: May require longer courses for immunocompromised or critically ill patients 3

Common Pitfalls and Caveats

The most critical error is using doxycycline as monotherapy for serious wound infections without considering the causative organisms. 1 Doxycycline lacks coverage against MRSA and has variable activity against streptococci, making it inappropriate for empiric treatment of most wound infections. 1

Key Warnings:

• Exceeding recommended dosage may increase side effects without improving efficacy 2
• Not indicated for serious intra-abdominal infections unless flora are known to be susceptible 4
• Inadequate source control (lack of proper debridement and drainage) will lead to treatment failure regardless of antibiotic choice 3
• Tetanus prophylaxis should be administered if not vaccinated within 10 years 1

Special Populations:

• Pregnancy: May be used for life-threatening illness despite general avoidance; adverse effects on teeth/bones are dose-related, so short courses (<14 days) before 6 months gestation may be acceptable 1
• Children <8 years: Generally avoided due to teeth staining, but may be necessary for serious infections like Rocky Mountain spotted fever 1

For most common wound infections, amoxicillin-clavulanate remains the preferred first-line agent due to superior coverage of both aerobic and anaerobic bacteria. 1, 3