What are the first-line medications for someone who had a tonic-clonic seizure?

First-Line Medications for Tonic-Clonic Seizures

The first-line medication for acute management of tonic-clonic seizures is an intravenous benzodiazepine (preferably lorazepam), followed by either valproate (30 mg/kg IV) or levetiracetam (30 mg/kg IV) as second-line treatment if seizures continue. 1, 2

Initial Management of Tonic-Clonic Seizures

First-Line Treatment

• For patients with active tonic-clonic seizures, IV benzodiazepines are the first-line treatment of choice 1, 2
• If IV access is not available, rectal diazepam should be administered 2
• Lorazepam is preferred over diazepam for IV administration due to its longer duration of action 2

Second-Line Treatment Options

If seizures continue after benzodiazepine administration, the following second-line options should be considered:

Valproate (30 mg/kg IV)

• Valproate has demonstrated high efficacy (63-88%) in controlling seizures within 20-60 minutes of administration 1
• It has a favorable safety profile with fewer adverse effects compared to phenytoin, particularly regarding hypotension 1
• As a second-line agent, valproate achieved seizure control in 79% of patients versus 25% with phenytoin 1
• Recommended dosing: 30 mg/kg IV infused at 6 mg/kg/hour, followed by maintenance infusion of 1-2 mg/kg/hour 3

Levetiracetam (30 mg/kg IV)

• Levetiracetam shows similar efficacy to valproate (68-73%) in controlling refractory seizures 1, 2
• It has minimal drug interactions and does not require serum level monitoring 4
• Recommended dosing: 30 mg/kg IV administered at 5 mg/kg per minute 3
• Levetiracetam lacks cytochrome P450 isoenzyme-inducing potential, making it suitable for patients on multiple medications 4

Clinical Decision Algorithm

1. Initial Assessment and Stabilization

   • Ensure airway, breathing, and circulation
   • Administer IV benzodiazepine (lorazepam preferred) 1, 2

2. If seizures continue after benzodiazepine administration:

   • Choose between valproate (30 mg/kg IV) or levetiracetam (30 mg/kg IV) based on:
     • Patient's comorbidities
     • Potential drug interactions
     • Previous medication response 3, 2

3. Specific considerations for choosing between valproate and levetiracetam:

   • Choose valproate if:

     • Male patient or post-menopausal female 5
     • No history of liver disease 6
     • No significant drug interactions are a concern 6

   • Choose levetiracetam if:

     • Female of childbearing potential (valproate should be avoided) 2, 5
     • Patient has liver disease 4
     • Patient is on multiple medications with potential interactions 4

Important Considerations and Pitfalls

• Avoid prophylactic anticonvulsants in patients with no history of seizures, as they do not reduce the risk of first seizure 1
• If anticonvulsants are started perioperatively, consider discontinuation after the perioperative period in patients without a history of seizures 1
• Monotherapy is preferred over polytherapy to minimize adverse effects and drug interactions 2
• Monitor for adverse effects:
  • Valproate: hepatotoxicity, thrombocytopenia, pancreatitis 6
  • Levetiracetam: behavioral changes, somnolence, dizziness 4
• Consider long-term treatment only after a second seizure, as 50% of patients who experience a first seizure will never have a second one 7

Long-Term Management After Initial Seizure Control

• For patients requiring ongoing treatment, consider transitioning to oral formulations of the same medication that controlled the acute seizure 2
• For partial onset seizures, carbamazepine may be considered as an alternative for long-term management 8, 9
• For primary generalized tonic-clonic seizures, valproic acid, lamotrigine, levetiracetam, or topiramate are effective options 5, 9
• Consider discontinuation of antiepileptic drugs after 2 seizure-free years, taking into account clinical factors 2