Antibiotic Dosing in Hemodialysis Patients
Core Dosing Principle
Increase the dosing interval rather than reducing the individual dose for antibiotics in hemodialysis patients, as concentration-dependent bactericidal activity requires adequate peak concentrations for efficacy. 1, 2
The fundamental error clinicians make is reducing individual doses, which leads to subtherapeutic peak concentrations and treatment failure. 1 Instead, maintain standard individual doses but extend the interval between doses to prevent drug accumulation between dialysis sessions. 1, 2
Timing of Administration
Administer all antibiotics immediately after hemodialysis sessions to prevent premature drug removal and ensure adequate therapeutic levels. 2, 3
- On dialysis days, give antibiotics post-dialysis, typically resulting in three-times-weekly dosing. 1, 2
- Never administer antibiotics before dialysis, as this results in subtherapeutic levels and treatment failure. 2
- This timing strategy facilitates directly observed therapy and optimizes drug exposure. 1
Antibiotic-Specific Dosing
Antibiotics Requiring NO Dose Adjustment
These drugs are hepatically metabolized and not significantly removed by dialysis:
- Rifampin: 600 mg once daily or 600 mg three times per week 1, 2
- Isoniazid: 300 mg once daily or 900 mg three times per week 1, 2
- Ethionamide: 250-500 mg/dose daily 1, 2
- Clindamycin: Standard dosing without adjustment 2
Antibiotics Requiring Interval Extension (Three Times Weekly)
These drugs are renally cleared or have active metabolites that accumulate:
- Pyrazinamide: 25-35 mg/kg per dose three times per week (NOT daily) 1, 2
- Ethambutol: 15-25 mg/kg per dose three times per week (NOT daily) 1, 2
- Levofloxacin: 750-1,000 mg per dose three times per week (NOT daily) 1, 2
- Moxifloxacin: 400 mg once daily without adjustment, given after dialysis 3
- Cycloserine: 250 mg once daily or 500 mg/dose three times per week (56% removed by dialysis) 1, 2
Injectable Aminoglycosides
Never use aminoglycosides as first-line therapy in hemodialysis patients due to substantial risk of irreversible ototoxicity. 2, 3
If absolutely necessary:
- Streptomycin, Kanamycin, Amikacin, Capreomycin: 12-15 mg/kg/dose two or three times per week (NOT daily) 1, 2
- Approximately 40% is removed by hemodialysis when given just before dialysis 1, 2
- Do not reduce individual doses despite renal failure, as these exhibit concentration-dependent killing 1
Vancomycin
For hemodialysis patients, give an initial loading dose of at least 15 mg/kg, then maintenance doses of 1,000 mg every 7-10 days in anuric patients. 4
- The FDA label specifies that in anuria, 1,000 mg every 7-10 days maintains stable concentrations 4
- For catheter-related infections, use 20 mg/kg (actual body weight) rounded to nearest 500-mg increment, administered after dialysis 2
- Therapeutic drug monitoring is essential, as 12-16% of patients achieve low levels (<12 mg/L) despite standard dosing 5
Cephalosporins
- Cefazolin: 20 mg/kg (actual body weight) rounded to nearest 500-mg increment, administered after dialysis 2
- Cephalosporins are preferred over aminoglycosides for gram-negative coverage due to lower toxicity risk 2
Beta-Lactams
- Amoxicillin: Administer immediately after each dialysis session 2
- Most beta-lactams are dialyzable and require post-dialysis supplementation 6
Critical Safety Considerations
Avoid nephrotoxic drug combinations (vancomycin + aminoglycosides, vancomycin + colistin) in hemodialysis patients to prevent further kidney damage. 2, 3
Monitoring Requirements
Therapeutic drug monitoring should be considered for:
- Cycloserine: Risk of neurotoxicity 2
- Ethambutol: Risk of optic neuritis 2
- All aminoglycosides: Risk of ototoxicity and nephrotoxicity 2
- Vancomycin: Highly variable levels, especially in non-anuric patients 5
Pharmacokinetic Principles
Hemodialysis removes antibiotics with:
High volume of distribution is the only guarantee that an antibiotic will not be eliminated by intensive dialysis techniques. 6