Vancomycin
Mechanism :
The bactericidal action of vancomycin results primarily from inhibition of cell-wall biosynthesis. In addition, vancomycin alters bacterial cell membrane permeability and RNA synthesis. There is no cross-resistance between vancomycin and other antibiotics. Vancomycin is not active in vitro against gram-negative bacilli, mycobacteria, or fungi.
Indication :
- Staphylococcal infections
- Methicillin resistant staphylococcus aureus (MRSA)
- Pseudomembranous colitis
- Enterococcus faecium.
Contraindications :
Vancomycin is contraindicated in patients with known hypersensitivity to this antibiotic.
Dosing :
Moderate MRSA infections:
By IV infusion over at least 60 minutes
40 mg/kg daily, given in 3-4 divided doses for 7-10 days. Max: 2 g daily.
Severe staphylococcal or other gram-positive infections, osteomyelitis, septicemia, soft tissue infections, endocarditis, meningitis:
Neonates:
<29 weeks of gestation: 15 mg/kg every 24 hours.
29-35 week of gestation: 15 mg/kg every 12 hours.
>35 week of gestation: 15 mg/kg every 8 hours.
1 month-18 years: 15-20 mg/kg every 8 hours (Max: 2 g daily), adjusted according to plasma concentrations.
Preoperative-Prophylaxis of endocarditis:
For patients undergoing dental, oral or upper respiratory tract surgery: 20 mg/kg slow IV infusion 1 hour before surgery. For patients undergoing GI or genitourinary procedure: 20 mg/kg with 1.5 mg/kg
gentamicin 1 hour before surgery.
Clostridium difficile infection:
First infection: 40 mg/kg/day PO in 4 doses for 10 days (Max: 125 mg/dose for non-severe infections and 500 mg/dose for severe infections). Can also use similarly for staphylococcal enterocolitis.
Recurrent infection: 40 mg/kg/day PO in 4 divided doses for 10-14 days, then 20 mg/kg/day PO 12 hourly for 7 days, then 10 mg/kg PO once a day for 7 days, then 10 mg/kg PO every 2nd-3rd day for 2-8 weeks. Max: 125 mg/dose.
Adverse Effect :
Infusion-Related Events: During or soon after rapid infusion of vancomycin, patients may develop anaphylactoid reactions, including hypotension, wheezing, dyspnea, urticaria, or pruritus. Rapid infusion may also cause flushing of the upper body (“red neck”) or pain and muscle spasm of the chest and back.
Others: Renal failure, pseudomembranous colitis symptoms, vertigo, dizziness, tinnitus, reversible neutropenia, thrombocytopenia, phlebitis, drug fever, nausea, chills, eosinophilia, rashes including exfoliative dermatitis, Stevens-Johnson syndrome, and vasculitis.
Interaction :
Anesthetic Agents: Concomitant administration of vancomycin has been associated with erythema and histamine-like flushing.
Amphotericin B, Aminoglycosides, Bacitracin, Polymyxin B, Colistin, Viomycin, or Cisplatin: Concurrent and/or sequential systemic or topical use when indicated, requires careful monitoring.
Renal Dose :
Dose in Renal Impairment GFR (mL/min)
| 20-50 | IV: 0.5–1 g every 12–24 hours Oral: dose as in normal renal function |
| 10-20 | IV: 0.5–1 g every 24–48 hours Oral: dose as in normal renal function |
| <10 | IV: 0.5–1 g every 48–96 hours Oral: dose as in normal renal function |
Dose in Patients undergoing Renal Replacement Therapies
| CAPD | Not dialysed. Dose as in GFR<10 mL/min |
| HD | Not dialysed. Dose as in GFR<10 mL/min |
| HDF/High flux | Dialysed. |
| CAV/VVH/HD | Dialysed. 1 g every 48 hours |
| CVVHD/HDF | Dialysed. 1 g daily |
Hepatic Dose :
No dose adjustment recommended.