What is the recommended doxycycline (Doxycycline) regimen for treating mycoplasma infections?

Doxycycline Regimen for Mycoplasma Infections

For mycoplasma infections, doxycycline should be administered at 100 mg orally twice daily for 7 days. 1, 2

Recommended Dosing by Age Group

• Adults and children ≥8 years weighing >45 kg:

  • Doxycycline 100 mg orally twice daily for 7 days 1, 3
  • This is the standard regimen for respiratory, urogenital, and other mycoplasma infections 2

• Children ≥8 years weighing <45 kg:

  • Erythromycin base or ethylsuccinate 50 mg/kg/day orally divided into 4 doses daily for 14 days, OR
  • Azithromycin 1 g orally in a single dose 1

• Children <8 years:

  • Doxycycline is contraindicated due to risk of dental staining 3
  • Alternative treatments such as macrolides should be used 4

Treatment Considerations by Infection Type

• Mycoplasma pneumoniae (respiratory):

  • Doxycycline 100 mg orally twice daily for 7-14 days 3, 2
  • For severe infections, treatment duration may be extended to 14-21 days 3

• Mycoplasma genitalium (urogenital):

  • Standard regimen: Doxycycline 100 mg orally twice daily for 7 days 1, 5
  • Note: Doxycycline alone has limited efficacy (45% cure rate) for M. genitalium 5
  • For suspected macrolide resistance, consider sequential therapy with doxycycline followed by moxifloxacin or extended azithromycin 6

Special Considerations

• Administration:

  • Take with adequate fluid (at least 8 oz of water)
  • Patient should remain upright for at least 1 hour after taking doxycycline to prevent esophagitis 3
  • Can be taken with or without food, though food may decrease gastrointestinal side effects

• Side Effects and Precautions:

  • Photosensitivity reactions can be severe; advise patients to avoid direct sunlight and use sun protection 3
  • Gastrointestinal side effects (nausea, vomiting, diarrhea) are common 3
  • Esophagitis and esophageal discomfort are potential side effects 3

• Contraindications:

  • Children under 8 years of age 1, 3
  • Pregnancy and breastfeeding (risk category D) 3
  • Known hypersensitivity to tetracyclines 3

Treatment Failures and Resistance

• For treatment failures:

  • Consider antimicrobial resistance testing if available 7
  • For M. genitalium infections with suspected resistance, alternative options include:
    • Moxifloxacin 400 mg once daily for 7-14 days 6
    • Extended azithromycin regimen (1 g initially, then 500 mg daily for 3 days) 6

• Emerging resistance concerns:

  • Macrolide resistance in M. genitalium is increasing globally (>50% in many regions) 7, 6
  • Quinolone resistance is also emerging 7
  • For multidrug-resistant infections, consultation with infectious disease specialists is recommended 8

Monitoring and Follow-up

• Clinical improvement should be evident within 48-72 hours of initiating therapy 3
• For persistent symptoms after completion of therapy, consider:
  • Antimicrobial resistance 7
  • Reinfection 1
  • Alternative diagnoses 1

Remember that doxycycline is effective against multiple mycoplasma species and is indicated for respiratory tract infections caused by Mycoplasma pneumoniae as well as urogenital infections caused by various mycoplasma species 2.