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Phenytoin Dizziness

My 12 year old son has been going up and down on his Dilantin. He has noctunal cluster seizures every night, but since upping the doseage of Dilantin, his seizures have gone from 20-30 per night to 5-10 per night. He was taking 100 mg extended phenytoin 2x daily - this did not help so neuro added a 50 mg chewable Dilantin before bed. This helped a little with no side effects. So a week later she added another 25 mg before bed, which again helped a bit. But now my son can barely walk, he is sooooo dizzy he walks around like he is drunk. He also had brain surgery almost 2 months ago and needs to continue with his physical therapy, but cannot because he can't even stand by himself. The neuro did levels and says they are fine but we cannot go up anymore, and the dizziness is a side effect of the Dilantin. So we need to decide if we want the seizures or side effects.

My question is this - for those of you who are taking Dilantin, did you see this kind of side effect when you started? And if so, does this go away, or did you have to decrease your dose? How long does it take for the dizziness to subside?  I would hate to see his seizures go back to where we started from, phenytoin seems to be the only med that has shown some improvement in my sons seizures in years.



so sorry to hear about the hard time your son is having. I have had two experiences with Dilantin (Pheytoin): my doctor first tried me on it 25years ago when I was first diagnosed with TLE, and frankly I just could not tolerate it, even though I kept at it for several years. It totally spaced me out when I got anywhere near the dose the doctor said I should be taking, and it never got any better.

In the end I stopped taking it... and ultimately switched to Depakote for 4-5years, which I tolerated very well (at least I thought!... check out my story elsewhere on this forum).

I was hospitalized some time ago with seizures, and they put me on Dilantin with Keppra and Depakote with intravenous Ativan. Some cocktail huh?! Again, the Dilantin spaced me out completely, as they had me on a high dose. Only when they dropped off the Dilantin and replaced it with Trileptal did the world stop spinning. So for sure, there are other drugs that may not have such side effects for your son.

But everyone of us is different, and we all react differently to the AEDs: I really encourage you to talk to your doctor about different possible drugs, or combination of drugs. And seriously consider the tradeoff of increased seizure activity versus heavy drug usage. It really is a compromise.

Also, (if by chance you haven't already) please make absolutely sure the seizures are truly epileptic though EEG monitoring, rather just than a doctors diagnosis.

Good luck,


Thank you for the response Drew.

Yes, we have tried almost every drug possible, including Depakote. Currently he is taking Lamictal, Topamax, Dilantin and Keppra. Before bed he also takes valium and lorazapam. We are in the process of weaning the Topamax, since it is the only drug that has not shown any decrease in seizures. The Keppra stopped his TC and Lamictal helps with the severity of the PC (when we try decreasing Lamictal, he becomes incontinent during seizures). And of course there is Dilantin, last night he only had 3 seizures (these are short PC seizures which last only 5 seconds each). I know going from 30 seizures nightly down to 3 is thanks to the Dilantin, because the other drugs he was on for many years now, the Dilantin is new to us, and showing great results. I think we are going to stick with it for a few more days, and call the doctor, hopefully she prescribes him a lower time release for his day dose and we keep the high dose at night. She said with the chewables, its quicker acting but shorter lasting, so the high chewable dose at night should ware off by morning, giving him less side effects during the day.

 I wish these night seizures were in fact NOT seizures, but we've had our share of EEGs. My son just had an anatomical hemispherectomy in April at the Cleveland Clinic. When he was still seizureing after the surgery, they did extensive tests to see if these were just post op seizures. He was put in VEEG monitoring unit and they said these are the exact same seizures as before surgery (except before surgery he had 10+ more intense startle seizures per day, instead of clusters at night). Since the seizure focus was removed, they are blaming it on a mirror focus, meaning the other side of the brain has learned how to seize on its own, without an actual focus. Yes, I know, it's a bummer. But they said in 6 months time, we should see less seizures after the brain has healed, at that time we will know what we are working with, and what drugs we should start weaning more of. That is why I am so insistant on keeping the Dilantin, if it is stopping the seizures, the other hemisphere might calm down and "forget" how to seize if it isn't constantly seizing.

This ended up being a lot longer than I was expecting, sorry this is so long, for those of you who are reading.


Is he taking the generic Phentoin (by Taro) or the brand name reformulated Dilantin? Phenobarbial seems to impact each person differently however, these two drugs are an ancient standard. However, I don't really know how much research has been devoted solely to their effects on growing children.


Of course he is taking the generic phenytoin, can't expect the insurance company to pay for the real thing. Actually the 100 mg time release is generic and the 50 mg chewable is Dilantin. The doctor had to explain to the pharmacy that the increased nightly dose of phenytoin MUST be in the chewable Dilantin form so it's quicker acting and worn off by morning, to try to avoid the side affects. Of course the insurance company questioned it, since the chewables don't come in generic.

Our neurologist is out for the week, but the neuro on call said to skip this morning's dose, and continue with the 100 mg time release tonight. Why the time release? Why not just give him the chewable before bed, when he actually HAS seizures. I gave him the 100 mg about an hour ago, and already he is complaining of feeling sick. I can't wait until our regular neuro comes back, she told me last week that she will be gone this entire week but will be back 6/16. She left us with a prescription of 30 mg phenobarbatol in case seizures got worse. We have not used it yet, thankfully the seizures are continuing to decrease. But if we have to give up this Dilantin, I am affraid they will probably get worse again. So frustrating!!!!!!!!!!!

When our neuro comes back, I am going to suggest a lower dose time release with the nightly chewable, or maybe just giving the time release once per day, instead of in the morning and night. How long does the time release stay in the system? I thought I heard Dilantin should be taken only once per day.

Yes, you can expect the insurance company to pay for it. If he is not tolerating anything but, then that is the medication that needs to be prescribed.

As for waiting a week for the neuro, why must you wait unless you really want your regular neurologist. Can your regular doctor "cover"? No access to a specialist, when you need them is not acceptable.

See a thread, on this site, called Had to go off Dilantin or search via my name and see how many other folks are having this difficulty with the generic and being covered by an HMO.

I could be wrong here but, each seizure only creates a neurological pathway that increases the risk of more seizures. If he is nocturnal and in that fixed pattern, that is preferrable to seizures from consciousness that can happen anytime.

My thoughts are with you. Let me know if you find the other thread and what you think.


I agree not having our regular neuro is unexceptable. I hate when I call and they say, she will be out all week. She said this will be the last week she will be gone for the rest of the summer. And there is a Neuro "on call" who has helped us in the past, but she is not familiar with Austins case, for example, she is the one who prescribed Ausitn take an additional Dilantin in the morning - when I questioned the timing (since he only seizures at night) the nurse was the only person available and she said "that is what the doctor ordered." What I should have done is contacted the epileptologists at Cleveland Clinic where he had his surgery - but they are hard to reach also and still not as familiar with Austin as his regular neuro that he has had since birth.

Some good news is he had ZERO seizures last night. And the only change was actually decreasing the Dilantin. His morning dose was skipped, I gave him the 100mg at night and skipped the extra chewable dose right before bed (since he was feeling queezie after giving the 100mg time release). So Dilantin is not only touchy with the dose in terms of side effects, but also in terms of effectiveness. I hope we finally found our right balance now.

too much dilantin will make u walk around drunk.....i been taking it for yrs i know..... i was in hosp for something else and my level was all out of whack.......the level should be between 10 - 20 i believe...not sure about that.....when they checked my level of dilantin it was at 37.5......almost lethal.....surprised i could still work.....i was walking around and stumbling into things and my speech was terrible.....please have his level checked again and keep an eye on it....take care and god bless.....


Yes, anytime my dosage of Dilantin is increased significantly, it takes my body about a week to adjust to it.  The last increase I had was 50mg to a total of 300mg a day.  It was like I was drugged up for about a week.  I also break up when I take it.  I take 200mg in the morning and 100mg at night.  It still makes me tired, but not to the extent it was when the dosage was first increased.  Hope this helps.

I've been on Dilantin for almost two years following surgery to install a new VP shunt (two TC's post surgery spaced six months apart and over a thirty "migraine" auras which I think were actually seizure related).

They started me on 100mg daily and bumped it up over time in order to see if it would decrease the auras.  I maxed out at 300Mg daily and the auras have all but disappeared (they left me with debilitating nausea and a wicked headache).

The Dilantin is doing it's job but the side effects, dizziness among them, is present and while not debilitating, it's an issue - I've described it as feeling like I'm drunk.  I have tripped, lost my balance and fallen a half dozen times in the last six months, but thankfully injured nothing more than my pride :-)

I'm on the fence about switching meds as having my symptoms under control is an enormous  relief , but I think the fact the drug makes me so clumsy and prone to falling will give me no choice but to eventually in the short term switch as eventually I am going to take a spill and seriously injure myself.

My husband used feel dizziness with high level oh phenytoin.

 He is now on Tegretol Retard and the dizziness has gone and the seizures are better controled



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