Difference between revisions of "Anticonvulsant levels and reloading"
| Line 36: | Line 36: | ||
===Phenytoin=== | ===Phenytoin=== | ||
*First-time load or level ~0 | *First-time load or level ~0 | ||
| − | **IV: | + | **IV: 18mg/kg at max rate of 25mg/min |
**PO: 18mg/kg as single dose or divided into 3 doses q2hr | **PO: 18mg/kg as single dose or divided into 3 doses q2hr | ||
*Level above 0 (to avoid over-dosing) | *Level above 0 (to avoid over-dosing) | ||
| Line 43: | Line 43: | ||
===Fosphenytoin=== | ===Fosphenytoin=== | ||
| − | *IV: | + | *IV: 18mg PE/kg at 100-150mg/min |
==See Also== | ==See Also== | ||
Revision as of 23:05, 28 January 2012
Contents
Background
- IV load can be performed with phenobarbital, phenytoin, valproate, levetiracetam
- Oral loading can be spread over day or more to avoid GI upset
Dose
Dose (mg) = ideal body weight (kg) X Vd X [desired level - current level (mcg/mL)]
Volume of Distribution
| Agent |
Volume of Distribution |
| Phenytoin (dilantin) | 0.8 |
| Carbamazepine (tegretol) | 0.8 |
| Phenobarbital | 0.6 |
| Valproate (depakote) | 0.2 |
Desired Level
- Pt's optimal level = desired level
- If optimal level unknown target upper end of therapeutic range:
- Phenytoin = 20 mcg/mL
- Valproate = 100 mcg/mL
- Phenobarbital = 40 mcg/mL
- If optimal level unknown target upper end of therapeutic range:
Loading
Phenytoin
- First-time load or level ~0
- IV: 18mg/kg at max rate of 25mg/min
- PO: 18mg/kg as single dose or divided into 3 doses q2hr
- Level above 0 (to avoid over-dosing)
- (100-level) X 0.25 X wt
- Give over 1hr
Fosphenytoin
- IV: 18mg PE/kg at 100-150mg/min
See Also
Source
DONALDSON 3/08 (from emedicine; Treiman 1997; Bourgeois, 1996)