Hello,

My neurologist prescribed Depakene to me which is another brand name for
Epilim. Let me recap a couple of things I know about this (but don't
forget: I am not a doctor or pharmacist!):

Each drug has a half-life (the time required for the concentration of the
drug in the blood to decline to half of its original value). Medications
with a short half-life, such as carbamazepine (the regular form, not
extended release) and valproate, pose a slightly greater problem than those
with a longer half-life, such as phenytoin or phenobarbital (brand names
differ per country). For drugs with a short half-life, it is important to
keep the interval between doses as close to the usual routine as possible.
Otherwise, the person risks adverse effects from high drug levels in the
blood or seizures from low drug levels.

I think your son is experiencing seizures because his blood levels are not
constant (too high / too low).

For drugs with a short half-time, it is better to take a couple of pills
during the day to keep the levels steady then taking them all at once in
the morning or one in the morning / one in the afternoon, etc.

The following is not definitive information, and applies
to my experience only! I use Depakote ER, an extended
release form of valproic acid. This is supposed to maintain
blood levels of valproic acid for 24 hours. One night, I
accidentally dropped 500mg on the floor, so took only
750mg that evening instead of the usual 1250 (x2 daily). I
had some jittering and jerking in the night and the next morning
(this had been essentially removed for three months), and
I took a valproic trough level blood test in the morning
(but for another reason...). The following night is when I
discovered the 500mg Depakote tablet on the floor. My
trough level before had been 107, but this time it had
dropped to 72 12 hours after the short dose (even though
I was using the ER version). Following this, I had five
"good" days (unusual for me - I'm starting on another drug
to try to fix this, too). I asked my neurologist, who has
done some work with dosing, and he advised me not
to read into variations anything significant, but to maintain
a precise dosing schedule (for both time and amount,
which is not always easy). He insists this is the best way
to gain control. I also asked about the effects of overdosing,
and it appears that seizures are not among them (do a
search on Depakote or valproic acid on www.google.com,
and you may be reassured). Some people can react badly
to any drug, though, and I could not tolerate Topamax
even in small quantities...
--DR

Thanks for your comments both :))

My son does react in unexpected ways to a variety of different things.
He's not very tolerant of drugs or injections/vaccinations.

Yesterday he didn't have any medication at all.  Today he was back to
his normal dosage.  He didn't have any fits/seizures yesterday or
today but he'd had 3 quite bad ones the day before yesterday.

Hello,
If, as you suspect, your son gets overloaded with the medication, he would begin to suffer side effects: lethargy, drowsiness, etc. It might be advisable to talk to his teachers to ask if they have noticed this behaviour at school?
As well, you could keep a lookout for this at home? Epilim is a drug with a long half life, meaning that one dose will last longer than a day, dependant on amount, so withholding a half dose would not have any real effect, as the prescribed dose is already in his system!
I wish you and your son well, Rich.