Effect of Valproic Acid Concentration on Photic Response
Condition: Photosensitive Epilepsy
MeSH terms: Epilepsy; Epilepsy, Reflex
Intervention: Valproic Acid; Placebo
Intervention description: The investigators will utilize intravenous sodium valproate at visit 3. Dosage will be individualized to each patient's body weight, age, and hepatic-enzyme-inducing status. Intravenous VPA dose predictions will be based upon population VPA pharmacokinetic parameters (Dutta 2003).; Each patient will have a placebo-infusion (with 0.9% NS or D5W) of 12-hour duration at visit 2.
Intervention MeSH terms: Valproic Acid
Phase: Phase 4
Study type: Interventional
Primary purpose: Treatment
Intervention model: Single Group Assignment
Masking: None (Open Label)
Enrollment: 13.0
Sex: All
Minimum age: 15 Years
Maximum age: 65 Years
Healthy volunteers: No
Keywords: epilepsy; photosensitive; valproic acid

Summary:

      We are trying to learn if small changes in the amount of a valproate in the blood (given
      through an IV) will change the way the brain reacts to flashing lights.
    

Eligibility criteria:

        Inclusion Criteria:

          -  Male or female patients

          -  Aged 15 to 65 years

          -  Patients with a diagnosis of epilepsy for which they are either taking up two AEDs,
             not including VPA/divalproex, or no AEDs

          -  Patients with a reproducible IPS-induced photo-paroxysmal responses of at least 7
             SPR-EEG units as measured at two different time points in the day (pm screening Study
             Visit 1 and am of Visit 2).

          -  Are in good health (with the exception of epilepsy).

          -  Able and willing to provide written informed consent.

        Exclusion Criteria:

          -  Patients not exhibiting a photo-paroxysmal-EEG response

          -  Patients with active psychogenic seizures

          -  Women who are pregnant or lactating

          -  Women of reproductive potential who do not agree to use effective birth-control
             methods during the study and for one week after receiving study drug.

          -  Patients taking any dosage form of VPA/divalproex within 4 weeks prior to the study

          -  Patients taking more than two concomitant AEDs

          -  Patients with any clinically significant laboratory abnormality, which in the opinion
             of the investigator, will exclude the patient from the study

          -  Patients who are suffering from active liver disease indicated by abnormal liver
             function tests greater than three times the upper limit of normal (AST and ALT),
             patients with porphyria, or patients with a family history of severe hepatic
             dysfunction

          -  Patients with a history of alcoholism, drug abuse, or drug addiction (within the past
             12 months)

          -  Patients with a history of sensitivity or allergic reaction to valproate / divalproex

          -  Patients who have a medical history which would contraindicate sodium valproate (VPA)
             administration

          -  Patients who have participated in any other trials involving an investigational
             product or device within 30 days of screening.

          -  Patients with clinically significant ECG abnormalities, as judged by the PI, at
             screening visit

          -  Patients with such poor intravenous access that the insertion of two intravenous
             catheters (one for sodium valproate infusion and one, in a contralateral arm vein, for
             serial blood sampling) for a 12-hour period is not possible.

          -  Patients who received benzodiazepines within one week of study initiation

          -  Status epilepticus within one year of screening

          -  Generalized tonic-clonic seizure within 24 hours of photic stimulation procedure