Difference between revisions of "Anticonvulsant levels and reloading"

(Reloading)
 
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==Background==
 
==Background==
*IV load can be performed with phenobarbital, phenytoin, valproate, levetiracetam
+
*IV load can be performed with phenobarbital, [[phenytoin]], valproate, levetiracetam
 
*Oral loading can be spread over day or more to avoid GI upset
 
*Oral loading can be spread over day or more to avoid GI upset
 
*May use IV vs PO reload at physican discretion<ref name="ACEP">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.</ref>
 
*May use IV vs PO reload at physican discretion<ref name="ACEP">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.</ref>
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|-
 
|-
 
| [[Carbamazepine]] (Tegretol)
 
| [[Carbamazepine]] (Tegretol)
|8 mg/kg suspension in single oral load  
+
|8mg/kg suspension in single oral load  
 
|NA
 
|NA
 
|-
 
|-
 
| [[Gabapentin]] (Neurontin)  
 
| [[Gabapentin]] (Neurontin)  
|900 mg/day oral (300 mg tid) for 3 days
+
|900mg/day oral (300mg tid) for 3 days
 
|NA  
 
|NA  
 
|-
 
|-
 
| [[Lamotrigine]] (Lamictal)  
 
| [[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
+
|6.5mg/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
 
|NA  
 
|NA  
 
|-
 
|-
 
| [[Levetiracetam]] (Keppra)  
 
| [[Levetiracetam]] (Keppra)  
|1,500 mg oral load
+
|1,500mg oral load
|Up to 60 mg/kg (rapid loading)
+
|1,000-1,500 mg IV
 
|-
 
|-
 
| [[Phenytoin]] (Dilantin)  
 
| [[Phenytoin]] (Dilantin)  
|20 mg/kg divided in maximum doses of 400 mg every 2 hours
+
|20mg/kg divided in maximum doses of 400mg every 2 hours
|18 mg/kg (max rate of 50 mg/min)  
+
|18mg/kg (max rate of 50mg/min)  
 
|-
 
|-
 
|[[Fosphenytoin]] (Cerebyx)  
 
|[[Fosphenytoin]] (Cerebyx)  
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| [[Valproate]] (Depacon)  
 
| [[Valproate]] (Depacon)  
 
|NA
 
|NA
|Up to 30 mg/kg IV (max rate of 10 mg/kg/min)
+
|Up to 30mg/kg IV (max rate of 10mg/kg/min)
 
|}
 
|}
  
 
==Reloading==
 
==Reloading==
*'''Dose (mg) = ideal body weight (kg) X Vd X [desired level - current level (mcg/mL)]'''
+
*'''Dose (mg) = [[ideal body weight estimation|ideal body weight]] (kg) X Vd X [desired level - current level (mcg/mL)]'''
  
 
===Volume of Distribution===
 
===Volume of Distribution===

Latest revision as of 15:25, 27 September 2019

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]

Anticonvulsant (brand name) PO Loading Dose IV Loading Dose
Carbamazepine (Tegretol) 8mg/kg suspension in single oral load NA
Gabapentin (Neurontin) 900mg/day oral (300mg tid) for 3 days NA
Lamotrigine (Lamictal) 6.5mg/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 NA
Levetiracetam (Keppra) 1,500mg oral load 1,000-1,500 mg IV
Phenytoin (Dilantin) 20mg/kg divided in maximum doses of 400mg every 2 hours 18mg/kg (max rate of 50mg/min)
Fosphenytoin (Cerebyx) NA 18 PE/kg IV (max rate of 150 PE/min)
Valproate (Depacon) NA Up to 30mg/kg IV (max rate of 10mg/kg/min)

Reloading

Volume of Distribution

Agent Volume of Distribution Desired Level
Phenytoin (dilantin) 0.8 20 mcg/mL
Carbamazepine (tegretol) 0.8 12 mcg/mL
Phenobarbital 0.6 40 mcg/mL
Valproate (depakote) 0.2 100 mcg/mL

See Also

References

  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.