Drug Category: Vitamins -- These agents are essential for normal metabolic processes.
| Drug Name | Pyridoxine (vitamin B-6) -- A 2004 American Academy of Neurology and Child Neurology Society practice parameter concluded that "there is insufficient evidence to recommend pyridoxine for the treatment of infantile spasms (Level U, Class III and IV evidence)." Two distinct treatment situations exist in which pyridoxine is used in patients with West syndrome: (1) IV administration during diagnostic EEG to assess whether patient's seizures and EEG abnormalities are related to pyridoxine deficiency. In this approach, administer 50-100 mg IV during diagnostic EEG; if dramatic improvement noted in EEG, patient believed to have pyridoxine-dependent seizures (2) Long-term oral administration: Effectiveness of long-term oral high-dose pyridoxine in West syndrome has been investigated in multiple open-label studies with promising results; most patients who respond to long-term oral high-dose pyridoxine do so within 1-2 wk of initiation. |
|---|---|
| Pediatric Dose | Initial dose: 10-20 mg/kg/d PO Titration: Increase by 10 mg/kg q3d Maintenance dose: 15-50 mg/kg/d PO (approximately 100-400 mg/d) |
| Contraindications | Documented hypersensitivity; do not administer IV to infants with cardiac disease |
| Interactions | Can decrease phenobarbital and phenytoin serum concentrations |
| Pregnancy | C - Safety for use during pregnancy has not been established. |
| Precautions | Usually well tolerated; adverse events include decreased appetite, nausea, vomiting, paresthesias, diarrhea, somnolence, and headache; abnormal liver function tests and low serum folic acid levels have been noted in some patients; long-term (cumulative) adverse effects can include severe sensory peripheral neuropathy, movement disorders, and ataxia |
Complications:
* Complications include dose-related, idiosyncratic, or long-term adverse effects from medications, including death.
Prognosis:
* The long-term overall prognosis is poor and is related directly to the etiology.
o Infants with idiopathic West syndrome have a better prognosis than do infants with symptomatic West syndrome. Only 14% of infants with symptomatic West syndrome have normal or borderline normal cognitive development, compared to 28-50% of infants with idiopathic West syndrome. Mental retardation is severe in 70% of patients, often with psychiatric problems such as autistic features or hyperactivity. Infrequently spasms may persist in adulthood. Fifty to seventy percent of patients develop other seizure types. Eighteen to fifty percent of patients will develop Lennox Gastaut syndrome.
o Subsets of patients among the symptomatic West syndrome group seem to have a better prognosis. A retrospective study of 17 children with trisomy 21 and infantile spasms found that 13 of 16 survivors were seizure free for more than 1 year and 10 no longer were taking anticonvulsants.
o A study of 15 children with neurofibromatosis type 1 and infantile spasms also reported a relatively benign seizure and cognitive outcome.
o Prognosis appears to be worse in infants with other seizure types, persistent EEG abnormalities, poor response to ACTH, and delayed initiation of treatment. One study showed that later onset, normal-to-mild psychomotor delay at the time of diagnosis, and good seizure control were factors related to better prognosis.
Medical/Legal Pitfalls:
* Failure to inform the patient's family of the risk for severe adverse effects, including death, from the use of either ACTH or oral steroids
* Failure to inform the patient's family of the risk for severe idiosyncratic reactions from two commonly used antiepileptic medications for West syndrome
o Valproate - Hepatotoxicity, pancreatitis
o Lamotrigine - Steven-Johnson syndrome, toxic epidermal necrolysis
* Failure to inform the patient's family of signs and symptoms to watch for that indicate severe adverse effects or idiosyncratic reactions
* Failure to instruct the family on what to do if they notice signs and symptoms indicating severe adverse effects or idiosyncratic reactions
* Failure to fully investigate and identify possible causes of the patient's West syndrome, including identification of tuberous sclerosis (a common cause of West syndrome), which can have implications for the entire family
* Failure to recognize signs and symptoms of West syndrome, which could result in failure to select an appropriate AED with proven efficacy; this could increase the risk for uncontrolled seizures that in turn increase the risk for injury and death.
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