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31 Cards in this Set
- Front
- Back
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Status Epilepticus definition.
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Seizure for more than 5 min
Technically longer than 30 min but seizures that last longer than 5 minutes are less likely to terminate and you want to treat |
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Clinical Manifestations.
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Limb convulsions
Longer than 5 minutes A/O x 0 Persistent upper gaze Incontinence Tachycardia, Hypertension, Tachypnea, Diaphoresis |
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Potential etiologies.
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Head trauma
Subtherapeutic drug levels |
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Goals in status epilepticus.
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Termination of seizure - If the convulsions stop but they don't regain mental status, they could be having non-convulsive status epilepticus where brain activity is still abnormal
Prevent recurrence (electrolyte abnormalities) Reduce adverse effects Stabilize ABC's |
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Non-pharmacologic therapy
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Assess and control airway, breathing and circulation
Make sure iv lines are not pulled out |
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Initial pharmacotherapy plan in status epilepticus
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Thiamine - to prevent wernicke's encephalopathy
D5W - to cover for possible hypoglycemia Fluids Benzodiazepine all IV |
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Which benzodiazepine is the best choice?
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Diazepam - Fast onset but very short acting so not good for recurrence (DOA 30 min - You'd want to give a long acting anticonvulsant also like phenytoin
Lorazepam - Longer duration of action - This is the drug of choice and has a greater affinity to the receptor. Don't have to give Phenytoin with this agent Midazolam - Very short acting - Must be administered continuous IV infusion which would be a problem with no IV access |
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What is the dose of Lorazepam?
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4 m IVP x 1
May repeat in 5 min if no response Max dose 8 mg |
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Which agent is good if the patient needs the agent IM (thrashing about)
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Midazolam 200 mcg/kg IM
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Monitoring
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ABG
Chem 7 CBC Consciousness Convusions Benzo side effects (sedation, respiratory depression) To find out the underlying cause |
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If initial therapy does not work, what would you give?
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Must think of infusion rate
Phenytoin or Fosphenytoin Phenytoin max rate 50 mg/min (25 mg/kg in elderly) Fosphenytoin max rate 150 mg/min |
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Phenytoin LD 10-20 mg/kg (lower for elderly, higher for obese)
May repeat 5 mg/kg if unresponsive to initial dose |
Fosphenytoin - Dose and infusion rate related paresthesia and pruritis of the face and groin
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Why does phenytoin have a lower max infusion rate?
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Vehicle is propylene glycol
Hypotension and arrhythmia's related to too-rapid infusion This is most likely to occur in elderly patient with cardiac disease or critically ill patients with low blood pressure Fosphenytoin is a prodrug with fewer BP and ECG changes |
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When do you want to check the phenytoin level after infusion has ended?
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2 hours
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Why is phenytoin used as a second line agent?
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Phenytoin works in up to 90% of patients
Infused over such a long time and works so slowly, so that is why it is used as a second line agent after a benzo. |
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Monitoring.
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Vital signs
ABGs ECG Phenytoin level 2 hours after infusion and right before first loading dose You need to start a loading dose in 12-24 hours (not immediately) |
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What can you do if the phenytoin doesn't work?
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You can give an additional 5 mg/kg of phenytoin or fosphenytoin equivalents
or IV Phenobarbital |
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Things you can do if the status epilepticus is still going on for more than 60 min
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IV Phenobarbital bolus every 1 hour until seizures stop
IV Valproate bolus followed by infusion IV Midazolam bolus followed by infusion IV Pentobarbital IV Propofol |
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When would you want to use Phenobarbital over Phenytoin?
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Patients who
Failed benzo + phenytoin Have a phenytoin allergy Have cardiac conduction abnormalities |
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What are the adverse events of phenobarbital?
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CNS Depression
Respiratory Depression Hypotension ***Controls seizures within minutes and there is no max dose*** |
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What would you do if the patient had no IV access?
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IM Midazolam
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If the patient was on clonazepam at home?
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Need a higher dose but respect maximum doses.
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If the patient had a history of atrial fibrillation?
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Phenobarbital
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How would you adjust the patients medication therapy if they had not been on phenytoin prophylaxis?
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You'd wanna go higher if the patient was obese
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Phenytoin half life is about 24 hours
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So check levels in 3-5 days
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You need to look at albumin when assessing Phenytoin levels. What is the equation to adjust serum phenytoin?
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Adjusted concentration = measured total concentration/ [(0.2 x albumin) + 0.1]
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What is the Phenytoin - Fluconazole interaction?
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Fluconazole is a 2C9 inhibitor, phenytoin is a substrate
Fluconazole increases the serum level of phenytoin |
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What is the concern with giving Zonisamide?
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It has a sulfa moiety
Sulfa allergy |
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Carbamazepine is an inducer and an auto-inducer.
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It can decrease the levels of other drugs as well as its own levels.
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Phenytoin
Substrate of 2c9, 2c19 Inducer of 3a, 2c |
Carbamazepine
Substrate 3a4 1a2 2c8 Inducer 1a2 2c 3a |
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AED's that are renally eliminated
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Gabapentin
Pregabalin Levetiracetamen Topiramate |
