Anticonvulsant levels and reloading: Difference between revisions

(/* LoadingSeizures 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...)
 
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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>


=== Dose ===
==Initial Loading<ref name="ACEP"></ref>==
Dose (mg) = ideal body weight (kg) X Vd X [desired level - current level (mcg/mL)]
{|class="wikitable"
|'''[[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)
|}


=== Volume of Distribution ===
==Reloading==
*'''Dose (mg) = [[ideal body weight estimation|ideal body weight]] (kg) X Vd X [desired level - current level (mcg/mL)]'''


{| style="width: 500px" border="1" cellpadding="1" cellspacing="1"
===Volume of Distribution===
 
{| class="wikitable"
|-
|-
| '''Agent<br/>'''
| '''Agent'''
| '''Volume of Distribution<br/>'''
| '''Volume of Distribution'''
| '''Desired Level'''
|-
|-
| Phenytoin (dilantin)  
| Phenytoin (dilantin)  
| 0.8
| 0.8
| 20 mcg/mL
|-
|-
| Carbamazepine (tegretol)
| Carbamazepine (tegretol)
| 0.8
| 0.8
| 12 mcg/mL
|-
|-
| Phenobarbital
| Phenobarbital
| 0.6
| 0.6
| 40 mcg/mL
|-
|-
| Valproate (depakote)
| Valproate (depakote)
| 0.2
| 0.2
|}
| 100 mcg/mL
 
=== 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
 
==Loading<ref>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>==
{|class="wikitable"
|'''Drug (With Selected References)'''
|'''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
|}
|}


==See Also==
==See Also==
*[[Seizure (Peds)]]
*[[Seizure]]
*[[Febrile Seizure]]
*[[Seizure (peds)]]
*[[Dilantin Load]]
*[[Seizure with known seizure disorder]]
*[[Depakote Loading]]
*[[Anticonvulsants]]


==Source==
==References==
<references/>
<references/>


[[Category:Drugs]]
[[Category:Pharmacology]]
[[Category:Neuro]]
[[Category:Neurology]]

Latest revision as of 03:59, 8 March 2021

Background

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.
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