Levetiracetam PO to IV Conversion
When switching from oral to intravenous levetiracetam, use a 1:1 dose conversion ratio as the bioavailability is equivalent between formulations. 1
Conversion Guidelines
Levetiracetam demonstrates complete bioequivalence between oral and IV formulations, making the conversion straightforward:
- The initial total daily intravenous dosage should be equivalent to the total daily dosage and frequency of oral levetiracetam 1
- Maintain the same dosing schedule (typically twice daily dosing)
- No dose adjustment is needed when converting between routes
For example:
- 500 mg PO twice daily → 500 mg IV twice daily
- 1000 mg PO twice daily → 1000 mg IV twice daily
- 1500 mg PO twice daily → 1500 mg IV twice daily
Administration Considerations
When administering IV levetiracetam:
- Standard administration: Infuse over 15 minutes 1
- Available in three concentrations: 500 mg/100 mL (5 mg/mL), 1000 mg/100 mL (10 mg/mL), or 1500 mg/100 mL (15 mg/mL) 1
- Do not further dilute the solution prior to use
- Maximum single dose is typically 1500 mg
Clinical Evidence Supporting 1:1 Conversion
The 1:1 conversion ratio is supported by pharmacokinetic studies showing bioequivalence between formulations:
- A study in healthy subjects demonstrated that single doses of levetiracetam 1,500 mg administered as a 15-minute IV infusion and as oral tablets were bioequivalent 2
- The geometric mean IV/oral ratios were 92.2% for AUC and 103.7% for Cmax, confirming bioequivalence 2
- Steady state is typically reached within 48 hours of consistent dosing 2
Special Considerations
Renal Impairment
Dose adjustments are necessary for patients with impaired renal function:
| Creatinine Clearance | Dosage | Frequency |
|---|---|---|
| >80 mL/min (normal) | 500-1,500 mg | Every 12 hours |
| 50-80 mL/min (mild) | 500-1,000 mg | Every 12 hours |
| 30-50 mL/min (moderate) | 250-750 mg | Every 12 hours |
| <30 mL/min (severe) | 250-500 mg | Every 12 hours |
| ESRD patients on dialysis | 500-1,000 mg | Every 24 hours* |
*Following dialysis, a 250-500 mg supplemental dose is recommended 1
Rapid Administration Options
Recent evidence suggests that faster administration may be safe in urgent situations:
- Rapid IV push administration (over 5 minutes) appears to be safe and well-tolerated 3, 4
- Faster administration may be beneficial in acute care settings requiring rapid attainment of therapeutic levels 3
- In status epilepticus, IV push administration was associated with shorter time to administration (12 vs. 44 minutes) compared to standard infusion 4
Switching Back to Oral Formulation
When IV therapy is no longer needed:
- Switch to oral levetiracetam at the equivalent daily dosage and frequency of the intravenous administration 1
- No titration period is required when switching back to oral formulation
- Maintain the same total daily dose and dosing schedule
Common Pitfalls to Avoid
Assuming dose adjustment is needed: Unlike some medications, levetiracetam requires no dose adjustment when switching between oral and IV routes due to its complete bioavailability.
Inadequate renal adjustment: Failing to adjust doses in patients with renal impairment can lead to drug accumulation and increased side effects.
Abrupt discontinuation: Avoid sudden withdrawal of levetiracetam to reduce the risk of increased seizure frequency and status epilepticus 1.
Overlooking compatibility issues: Levetiracetam IV is compatible with lorazepam, diazepam, and valproate sodium, but compatibility with other antiepileptic drugs is not established 1.