IV administration of LEV and LCS is initially preferred over ET in the hospital setting. Bioavailability pharmacokinetic data are available in healthy individuals but not in acutely ill patients.

This is a prospective observational study of adult patients aged 18 years old and above who received IV LEV and/or LCS in the hospital setting. Serum levels of LEV and LCS were measured during IV administration and repeated at least 24 hours after conversion to ET. Drug costs for transitioning from IV to ET were estimated.  

Of 45 patients, 36 received LEV and 9 LCS with mean age of 63 ± 19 and 72 ± 15, respectively.

Serum levels are described as means in mcg/dL. Amongst those with history of epilepsy or seizures, 20 (55.6 %) had IV LEV level of 9.52 ± 11.56 and ET LEV level of 22.38 ± 13.62 (P = 0.727); 5 (55.6 %) had IV LCS level of 9.28 ± 3.91 and ET LCS level of 9.76 ± 4.74 (P = 0.516).  In the seizure prophylaxis group, 16 (44.4 %) had IV LEV of 10.16 ± 5.13 and ET LEV level of 12.13±7.37 (P = 0.294); 4 (44.4 %) had IV LCS level of 4.25 ± 0.26 and ET LCS level of 6.22 ± 0.56 (P = 0.013).

No patients had seizures within 48 hours of transition.  Overall drug cost saving was $ 590.30 for LEV and $10,004.50 for LCS.

This preliminary data shows that IV and ET therapeutic levels are comparable suggesting that ET is as effective as IV in the hospital setting. There is also potential drug cost saving when transitioning from IV to ET.