Medication Summary
In postoperative endophthalmitis, parenteral therapy is not necessary unless evidence of infection exists outside the globe.
In other forms of endophthalmitis, administer broad-spectrum antibiotics once cultures have been obtained. An ophthalmologist usually administers intravitreal and subconjunctival injections. The following list of systemic antibiotics can be administered in conjunction with injection.
Antibiotics
Class Summary
Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the context of the clinical setting.
Vancomycin (Vancocin)
Empiric coverage for gram-positive organisms including B cereus. DOC for both intravitreal and systemic administration; excellent gram-positive coverage and has added advantage of providing better coverage against resistant organisms; bactericidal against most organisms and bacteriostatic for enterococci; inhibits cell wall biosynthesis, interfering with cell-membrane permeability and RNA synthesis.
After systemic administration, drug penetrates most tissues including vitreous, especially if the blood-ocular barrier is compromised. Use creatine clearance to adjust dose in patients with renal impairment.
Gentamicin (Gentacidin, Garamycin)
Empiric coverage for gram-negative organisms including P aeruginosa. First choice aminoglycoside for systemic gram-negative coverage; bactericidal inhibitor of protein synthesis (30S ribosomal subunit).
Dosing regimens are numerous; adjust dose based on CrCl.
Ceftazidime (Fortaz, Ceptaz)
Third-generation cephalosporin with broad gram-negative coverage but decreased efficacy to gram-positive organisms; gram-negative coverage includes Enterobacter, Citrobacter, Serratia, Neisseria, Providencia, and Haemophilus species.
Cephalosporins bind to one or more of the penicillin-binding proteins and prevent cell wall synthesis inhibiting bacterial growth.
Ceftriaxone (Rocephin)
Third-generation cephalosporin that crosses blood brain barrier. Active against resistant bacteria including gonococci, H influenzae, and other gram-negative organisms.
Used in suspected hematogenous source for endophthalmitis in combination with vancomycin while cultures are pending. Cephalosporins bind to the penicillin binding protein and prevent cell wall synthesis, which inhibits bacterial growth.
Cefotaxime (Claforan)
Third-generation cephalosporin that has broad gram-negative coverage but lower efficacy for gram-positive organisms. Cephalosporins bind to one or more of the penicillin-binding proteins and prevent cell wall synthesis inhibiting bacterial growth.
Clindamycin (Cleocin)
Use in IV drug abusers or penetrating trauma with soil contamination for suspected B cereus infection. Semisynthetic antibiotic that inhibits bacterial protein synthesis by interfering with peptide bond formation at the 50S ribosomal subunit; has both bacteriostatic and bactericidal activity.
Antifungal
Class Summary
For suspected candidal or Aspergillus infection. Indicated in patients who are immunosuppressed, who have indwelling venous catheters, or who are currently taking broad-spectrum antibiotics.
Amphotericin B (AmBisome)
Fungistatic or fungicidal depending on concentration attained in body fluids; polyene antibiotic produced by a strain of Streptomyces nodosus. Changes permeability of fungal cell membrane by binding to sterols, which causes fungal cell death as intracellular components leak out.
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Severe endophthalmitis. Courtesy of Ron Afshari Adelman MD, MPH, MBA, FACS, Yale Medical Group.
