What is the best IV anti-epileptic to load a patient on Vimpat (lacosamide), Topomax (topiramate), and Briviact (brivaracetam) with a breakthrough seizure?

Best IV Anti-Epileptic for Breakthrough Seizure in Patient on Multiple AEDs

Levetiracetam (Keppra) is the best IV anti-epileptic to load a patient who is already on Vimpat (lacosamide), Topamax (topiramate), and Briviact (brivaracetam) with a breakthrough seizure. 1

Rationale for Levetiracetam Selection

Efficacy

• Levetiracetam has demonstrated efficacy comparable to other second-line agents for status epilepticus, with success rates of 44-73% in stopping seizures 2
• The American Academy of Neurology notes that the ESETT trial showed levetiracetam has similar efficacy to fosphenytoin and valproate for status epilepticus 1

Safety Profile

• Levetiracetam has minimal adverse effects compared to other IV anti-epileptics 1
• Can be administered rapidly with minimal dilution (30-50 mg/kg IV) 3
• Does not cause significant cardiac conduction abnormalities or hypotension 1

Drug Interaction Considerations

• The patient is already on multiple anti-epileptic drugs, making drug interactions a critical concern
• Levetiracetam has minimal drug interactions, making it ideal for patients on multiple medications 1
• Particularly important since the patient is already on brivaracetam (Briviact), which is a derivative of levetiracetam with a similar mechanism of action 4, 5

Dosing Recommendations

• Loading dose: 30-50 mg/kg IV administered at a rate of up to 100 mg/min 2, 1
• Can be administered undiluted via peripheral IV access 1
• High serum levels can be achieved rapidly and safely with minimal infusion volume 3

Alternative Options and Their Limitations

Valproate

• While effective (88% success rate), may have interactions with existing medications 2
• Side effects include gastrointestinal disturbances, somnolence, tremor, and local irritation 1

Phenytoin/Fosphenytoin

• Lower success rate (56%) compared to other options 2
• Significant risks of hypotension, cardiac dysrhythmias, and purple glove syndrome 2
• Requires slower infusion rate, delaying therapeutic effect

Phenobarbital

• Effective (58% success rate) but causes significant respiratory depression and hypotension 2
• These side effects are particularly problematic in emergency settings

Propofol

• Requires intubation and respiratory support
• Significant risk of hypotension (42% of patients) 2
• Should be reserved for refractory cases requiring intubation

Important Clinical Considerations

• Monitor vital signs during and after infusion
• Perform EEG if mental status does not improve after seizure cessation to rule out non-convulsive status epilepticus
• Consider investigating potential causes of breakthrough seizure with laboratory tests (electrolytes, glucose, calcium, magnesium, CBC, toxicology)
• Brivaracetam (Briviact) is structurally similar to levetiracetam, but their concurrent use is still considered safe as they have different binding affinities to SV2A 5, 6, 7

Potential Pitfalls to Avoid

• Avoid phenytoin/fosphenytoin due to higher risk of adverse effects and drug interactions
• Do not delay treatment while waiting for laboratory results
• Remember that the patient's current medication regimen already includes multiple mechanisms of action, so adding a medication with a different mechanism may be more beneficial than increasing doses of current medications

In conclusion, levetiracetam offers the best balance of efficacy, safety profile, and minimal drug interactions for a patient already on multiple anti-epileptic drugs presenting with breakthrough seizures.