Levetiracetam Dosing for a 64-Year-Old Patient with CrCl 49 mL/min
For a 64-year-old patient with a creatinine clearance of 49 mL/min, the recommended dose of Keppra (levetiracetam) is 500 mg twice daily (1000 mg/day total). 1
Pharmacokinetic Considerations in Renal Impairment
- Levetiracetam is primarily eliminated through renal excretion with approximately 66% of the administered dose excreted unchanged in urine 1
- Total body clearance of levetiracetam is reduced by approximately 50% in patients with moderate renal impairment (CrCl 30-50 mL/min) 1
- The patient's CrCl of 49 mL/min falls into the moderate renal impairment category, requiring dose adjustment 1
- Clearance of levetiracetam is directly correlated with creatinine clearance 1
Specific Dosing Recommendations
- For patients with CrCl between 30-50 mL/min, the FDA label recommends reducing the total daily dose by approximately 50% 1
- Standard adult dosing of levetiracetam typically ranges from 1000-3000 mg/day divided into two doses 2
- Therefore, for this 64-year-old patient with CrCl 49 mL/min, the appropriate starting dose would be 500 mg twice daily 1
Age-Related Considerations
- Elderly patients (>60 years) have decreased total body clearance of levetiracetam by approximately 38% compared to younger adults 1
- The half-life of levetiracetam is approximately 2.5 hours longer in elderly patients 1
- This decreased clearance is primarily due to age-related decline in renal function 1
- GFR decreases approximately 8 mL/min each decade after age 40 3
Monitoring Recommendations
- Regular monitoring of renal function is essential as levetiracetam clearance correlates directly with creatinine clearance 1
- If renal function deteriorates further (CrCl <30 mL/min), additional dose adjustments may be necessary 1
- Monitor for clinical efficacy and adverse effects, particularly somnolence and asthenia, which are the most common side effects 2
- No routine therapeutic drug monitoring is required for levetiracetam, but it may be beneficial in patients with altered pharmacokinetics such as the elderly 4
Common Pitfalls to Avoid
- Avoid underdosing, which may lead to inadequate seizure control 5
- Avoid overdosing, which may increase the risk of adverse effects, particularly in patients with renal impairment 1
- Do not rely solely on serum creatinine to estimate renal function in elderly patients, as decreased muscle mass may result in falsely low values 3
- Remember that polypharmacy, common in elderly patients, may affect drug metabolism and clearance 6