Anticonvulsant levels and reloading: Difference between revisions
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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> | ||
==Loading<ref name="ACEP"></ref>== | ==Initial Loading<ref name="ACEP"></ref>== | ||
{|class="wikitable" | {|class="wikitable" | ||
|''' | |'''[[Anticonvulsant]] (brand name)''' | ||
|'''Loading Dose | |'''PO Loading Dose''' | ||
|'''IV Loading Dose''' | |||
|- | |- | ||
| [[Carbamazepine]] (Tegretol)| | | [[Carbamazepine]] (Tegretol) | ||
single oral load | |8mg/kg suspension in single oral load | ||
|NA | |||
|- | |- | ||
| [[Gabapentin]] (Neurontin) | | | [[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 | |||
IV | |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== | ==Reloading== | ||
*'''Dose (mg) = [[ideal body weight estimation|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=== | ||
{| class="wikitable" | |||
{| | |||
|- | |- | ||
| '''Agent | | '''Agent''' | ||
| '''Volume of Distribution | | '''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 | |||
|} | |} | ||
==See Also== | ==See Also== | ||
*[[Seizure]] | *[[Seizure]] | ||
*[[Seizure ( | *[[Seizure (peds)]] | ||
*[[ | *[[Seizure with known seizure disorder]] | ||
*[[Anticonvulsants]] | |||
== | ==References== | ||
<references/> | <references/> | ||
[[Category: | [[Category:Pharmacology]] | ||
[[Category: | [[Category:Neurology]] |
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
- Dose (mg) = ideal body weight (kg) X Vd X [desired level - current level (mcg/mL)]
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 |