Anticonvulsant levels and reloading: Difference between revisions
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==Reloading== | ==Reloading== | ||
=== Dose === | === Dose === | ||
Dose (mg) = ideal body weight (kg) X Vd X [desired level - current level (mcg/mL)] | '''Dose (mg) = ideal body weight (kg) X Vd X [desired level - current level (mcg/mL)]''' | ||
=== Volume of Distribution === | === Volume of Distribution === |
Revision as of 04:16, 3 June 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]
Loading[1]
Drug (with brand name) | Loading Dose and Route of Administration |
Carbamazepine (Tegretol) | 8 mg/kg oral suspension;
single oral load; IV not available |
Gabapentin (Neurontin) | 900 mg/day oral (300 mg tid) for 3 days;
IV not available |
Lacosamide (Vimpat) | Oral and IV formulations available and safe;
loading dosages not studied |
Lamotrigine (Lamictal) | 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) | 1,500 mg oral load;
rapid IV loading safe and well tolerated in doses up to 60 mg/kg |
Phenytoin (Dilantin) | 20 mg/kg divided in maximum doses of 400 mg every 2 h orally;
or 18 mg/kg IV at maximum rate of 50 mg/min |
Fosphenytoin (Cerebyx) | 18 PE/kg IV at maximum rate of 150 PE/min;
IM administration possible |
Valproate (Depacon) | Up to 30 mg/kg IV at max rate of 10 mg/kg/min IV |
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 |
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: