Anticonvulsant levels and reloading: Difference between revisions
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|'''Loading Dose and Route of Administration'''
|'''Loading Dose and Route of Administration'''
|-
|-
| [[Carbamazepine]] (Tegretol)||8 mg/kg oral suspension;
| [[Carbamazepine]] (Tegretol)||PO: 8 mg/kg suspension in single oral load  
single oral load;
IV: not available  
IV not available  
|-
|-
| [[Gabapentin]] (Neurontin) ||900 mg/day oral (300 mg tid) for 3 days;
| [[Gabapentin]] (Neurontin) ||PO: 900 mg/day oral (300 mg tid) for 3 days
IV not available  
IV: not available  
|-
|-
| [[Lacosamide]] (Vimpat) ||Oral and IV formulations available and safe;
| [[Lacosamide]] (Vimpat) ||PO: dosages not studied
loading dosages not studied  
IV: not studied  
|-
|-
| [[Lamotrigine]] (Lamictal) ||6.5 mg/kg single oral load if on lamotrigine;
| [[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
for >6 mo without a history of rash or intolerance in the past and only off lamotrigine for <5 days;
IV: not available  
IV not available  
|-
|-
| [[Levetiracetam]] (Keppra) ||1,500 mg oral load;
| [[Levetiracetam]] (Keppra) ||PO: 1,500 mg oral load
rapid IV loading safe and well tolerated in doses up to 60 mg/kg  
IV: 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;
| [[Phenytoin]] (Dilantin) ||PO: 20 mg/kg divided in maximum doses of 400 mg every 2 hours
or 18 mg/kg IV at maximum rate of 50 mg/min  
IV: 18 mg/kg at maximum rate of 50 mg/min  
|-
|-
| [[Fosphenytoin]] (Cerebyx) ||18 PE/kg IV at maximum rate of 150 PE/min;
| [[Fosphenytoin]] (Cerebyx) ||PO:
IM administration possible  
IV: 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
| [[Valproate]] (Depacon) ||PO:
IV: Up to 30 mg/kg IV at max rate of 10 mg/kg/min
|}
|}


Revision as of 15:21, 25 November 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:

  1. Phenytoin
  2. Carbamazepine
  3. Phenobarbital
  4. Valproate

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

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

See Also

Source

  1. ↑ 1.0 1.1 Seizures ACEP Policy committee . Clinical Policy: Critical Issues in the Evaluation and Management of Adult Patients Presenting to the Emergency Department With Seizures. Ann Emerg Med. 2014;63(4):437–447.e15. doi:10.1016/j.annemergmed.2014.01.018.
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