Anticonvulsant levels and reloading: Difference between revisions
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==Loading== | ==Loading== | ||
* | ===Phenytoin=== | ||
*First-time load or level ~0 | |||
**IV: 10-20mg/kg at max rate of 25mg/min | **IV: 10-20mg/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 | ||
===Fosphenytoin=== | |||
*IV: 10-20mg phenytoin equivalent at max rate of 150mg/min | |||
===Phenytoin=== | |||
*(100-level) X 0.25 X wt | |||
*Give over 1hr | |||
==See Also== | ==See Also== | ||
Revision as of 09:55, 4 October 2011
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: 10-20mg/kg at max rate of 25mg/min
- PO: 18mg/kg as single dose or divided into 3 doses q2hr
Fosphenytoin
- IV: 10-20mg phenytoin equivalent at max rate of 150mg/min
Phenytoin
- (100-level) X 0.25 X wt
- Give over 1hr
See Also
Source
DONALDSON 3/08 (from emedicine; Treiman 1997; Bourgeois, 1996)