Question | Answer |
Cause kidney stones | topiramate (Topamax)
zonisamide (Zonegran)
* drink plenty of water to reduce risk |
sulfonamide anti-convulsant | zonisamide (Zonegran) and topiramate (topamax) |
Dose conversion between fosphenytoin and phenytoin | Fosphenytoin 125-150mg = phenytoin 100mg |
Free phenytoin level calculation for albumin < 4 | measured conc / [(0.2 x albumin) + 0.1] |
Free phenytoin level calculation for CrCl < 10 | measured conc / [(0.2 x albumin) + 0.1] |
Phenytoin therapeutic range | 10-20mcg/mL
> 20 mcg/mL = lateral nystagmus, > 30 ataxia, > 40 decreased mentation, > 100 death
Free phenytoin level: 1-2.5 |
Phenytoin ADRs | P-450 inducer
Hirsutism
Enlarged gums
Nystagmus
Yellow-browning of skin
Teratogenecity
Osteomalacia
Interference with B12 metabolism (hence anemia)
Neuropathies (verigo, ataxia, headache) |
Autoinduction | Carbamazepine (~ 21 days) |
BBW of VPA | hepatoxicity especially in children < 2 yo
pancreatitis
teratogenecity |
BBW carbamazepine | blood dyscrasias
SJS (esp in asians + for HLA-B*1502) |
Schedule of Fycompa (perampanel) | C-III |
Schedule of Phenobarb | C-IV |
Schedule of clobazam (Onfi) | C-IV |
Schedule of pregablin (Lyrica) | C-V |
Schedule of Lincosamide (Vimpat) | C-V |
Schedule of ezogabine (Potiga) | C-V |
Severe life-threatening rash esp when co-administered with VPA | lamotrigine (Lamictal) |
DOC for absence seizures | ethosuximide (Zarontin) |
Max IV rate for phenytoin | 50mg/min |
Phenytoin IV solution | NS only due to propylene glycol |
Oligohidrosis | Zonisamide |
Treatment of febrile seizures | diazepam or lorazepam |
Dose of Phenytoin for status epilepticus | 15-20mg/kg LD
5-6 mg/kg/d divided TID (~300mg/d) |