Recommended Dosage of Invanz (Ertapenem) for Adults with Normal Renal Function
The recommended dosage of Invanz (ertapenem) for adults with normal renal function is 1 gram once daily, administered intravenously or intramuscularly. 1
Dosing Details
Ertapenem has pharmacokinetic properties that allow for convenient once-daily dosing:
- Standard adult dose: 1 gram once daily 1, 2
- Administration routes:
- Intravenous (IV) infusion
- Intramuscular (IM) injection
Pharmacokinetic Properties Supporting Once-Daily Dosing
Ertapenem has several key characteristics that enable once-daily dosing:
- Long half-life of approximately 4 hours in adults 2
- High protein binding
- Sufficient serum concentrations maintained above the MIC for most susceptible organisms for 12-24 hours 3
Special Population Considerations
Renal Impairment
- Normal to moderate renal function (CrCl ≥31 mL/min/1.73 m²): No dosage adjustment needed 1
- Severe renal impairment (CrCl ≤30 mL/min/1.73 m²): Reduce dose to 0.5 grams every 24 hours 1
- End-stage renal disease on hemodialysis: 0.5 grams daily with administration after dialysis on dialysis days 1
Elderly Patients
- No dosage adjustment necessary for elderly patients with normal (for their age) renal function 1
- Consider monitoring renal function as elderly patients may have age-related decreases in creatinine clearance
Hepatic Impairment
- No dosage adjustment recommended based on hepatic function 1, 2
- Ertapenem does not appear to undergo significant hepatic metabolism 1
Clinical Considerations
Therapeutic Efficacy Factors
- Urinary pH may affect drug efficacy - ertapenem is more rapidly effective in acidic urine 4
- In critically ill patients with severe sepsis, pharmacokinetics can be variable and may result in suboptimal unbound concentrations in some patients 5
Monitoring
- Routine monitoring of drug levels is not necessary for most patients 3
- Consider monitoring in patients with:
- Severe renal impairment
- Critical illness
- Poor treatment response
Common Pitfalls to Avoid
Renal function assessment: Always assess renal function before initiating therapy, as dose adjustments are required for severe renal impairment
Duration of therapy: Ensure appropriate duration based on infection type and clinical response
Drug interactions: While ertapenem has minimal drug interactions (not a substrate or inhibitor of P-glycoprotein or cytochrome P450 enzymes), probenecid can reduce renal clearance of ertapenem by competing for active tubular secretion 1
Administration considerations: When given intravenously, ertapenem should be infused over 30 minutes to minimize vein irritation
Ertapenem's once-daily dosing regimen, broad spectrum of activity, and minimal drug interactions make it a convenient option for treating various infections in adults with normal renal function.