Anticonvulsant levels and reloading: Difference between revisions
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***Valproate = 100 mcg/mL | ***Valproate = 100 mcg/mL | ||
***Phenobarbital = 40 mcg/mL | ***Phenobarbital = 40 mcg/mL | ||
***Carbamazepine = 12 mg/L | |||
==Reloading== | ==Reloading== |
Revision as of 06:44, 14 December 2014
Background
- IV load can be performed with phenobarbital, phenytoin, valproate, levetiracetam
- Oral loading can be spread over day or more to avoid GI upset
- May use IV vs PO reload at physican discretion[1]
Initial Loading[1]
Drug (with brand name) | Loading Dose and Route of Administration |
Carbamazepine (Tegretol) | PO: 8 mg/kg suspension in single oral load
IV: not available |
Gabapentin (Neurontin) | PO: 900 mg/day oral (300 mg tid) for 3 days
IV: not available |
Lacosamide (Vimpat) | PO: dosages not studied
IV: not studied |
Lamotrigine (Lamictal) | PO: 6.5 mg/kg single oral load if on lamotrigine for >6 mo without a history of rash or intolerance in the past and only off lamotrigine for <5 days
IV: not available |
Levetiracetam (Keppra) | PO: 1,500 mg oral load
IV: rapid IV loading safe and well tolerated in doses up to 60 mg/kg |
Phenytoin (Dilantin) | PO: 20 mg/kg divided in maximum doses of 400 mg every 2 hours
IV: 18 mg/kg at maximum rate of 50 mg/min |
Fosphenytoin (Cerebyx) | PO:
IV: 18 PE/kg IV at maximum rate of 150 PE/min IM: administration possible |
Valproate (Depacon) | PO:
IV: Up to 30 mg/kg IV at max rate of 10 mg/kg/min |
Levels
Medications with verifiable levels include:
Desired Levels
- 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
- Carbamazepine = 12 mg/L
- If optimal level unknown target upper end of therapeutic range:
Reloading
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 |