What is the dosing regimen for Bactrim (sulfamethoxazole/trimethoprim) in the treatment of hordeolum cellulitis?

Bactrim Dosing for Hordeolum Cellulitis

For hordeolum cellulitis, the recommended dosage of Bactrim (sulfamethoxazole/trimethoprim) is 1 double-strength tablet (160 mg trimethoprim/800 mg sulfamethoxazole) orally twice daily for 7-10 days. 1

Rationale for Dosing

• Bactrim is effective against purulent cellulitis, including hordeolum cellulitis, which is often caused by Staphylococcus aureus, including community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) 1
• The dosage of 1 double-strength tablet (160 mg trimethoprim/800 mg sulfamethoxazole) twice daily is the standard adult dose for skin and soft tissue infections 1, 2
• For skin infections like hordeolum cellulitis, a 7-10 day course is typically recommended to ensure complete resolution and prevent recurrence 2, 3

Weight-Based Considerations

• For optimal outcomes, weight-based dosing should be considered, particularly in patients who are overweight or obese 4
• Adequate dosing is defined as ≥5 mg/kg/day of the trimethoprim component 4
• Inadequate dosing has been associated with a significantly higher clinical failure rate (30% vs 17%) compared to adequate weight-based dosing 4

Special Populations

• For patients with impaired renal function:
  • Creatinine clearance >30 mL/min: standard regimen 2, 3
  • Creatinine clearance 15-30 mL/min: half the usual regimen 2, 3
  • Creatinine clearance <15 mL/min: not recommended 2, 3
• Bactrim is contraindicated in:
  • Pregnant women in the third trimester 1
  • Children under 2 months of age 2, 3
  • Patients with known hypersensitivity to sulfonamides 2

Efficacy and Monitoring

• Bactrim has demonstrated high efficacy rates (91%) in treating skin infections in areas with high prevalence of CA-MRSA 5
• Clinical improvement should be evident within 48-72 hours of initiating therapy 1
• If no improvement is seen within 72 hours, consider:
  • Possible resistance to Bactrim
  • Need for incision and drainage if abscess formation has occurred
  • Alternative antibiotic therapy 1, 5

Potential Adverse Effects

• Common adverse effects include rash, urticaria, nausea, vomiting, and gastrointestinal disturbances 6
• Rare but serious adverse effects include:
  • Agranulocytosis (case reports exist even in healthy adults) 7
  • Stevens-Johnson syndrome
  • Toxic epidermal necrolysis 2
• Monitor for signs of bone marrow suppression, especially in prolonged therapy or high doses 7, 8

Alternative Options

• If Bactrim is contraindicated or not tolerated, consider:
  • Clindamycin 300-450 mg orally three times daily 1
  • Doxycycline 100 mg orally twice daily (not for children under 8 years) 1
  • Linezolid 600 mg orally twice daily (more expensive option) 1

Clinical Pearls

• Incision and drainage should be performed if fluctuance is present, but antimicrobial therapy is still recommended for surrounding cellulitis 1
• Patient should be advised to complete the full course of antibiotics even if symptoms improve rapidly 1
• Warm compresses applied to the affected eye can help with symptomatic relief and may promote drainage 1