Phenytoin and Carbamezapine combination therapy


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Hello everyone. New to the forum. Just wanted to know if there is anyone out there that has ever changed their medication from phenytoin /dilantin to carbamezepine/tegretol and if so how was their experience.

I have been on phenytoin for 9 years straight but after some breakthrough seizures we tried to increase the dosage from 300mg to 400mg per day. It seems like a small dose but it came with all sorts of side effects, the most disturbing being peripheral neuropathy. Getting back to 300mg didnt help the situation so doc has me slowly transferring to carbamezapine.

So the last 2 weeks I have been taken down to 200 mg phenytoin and added 400mg carbamezepine. The plan is to gradually phase out phenytoin. The current 'combination' therapy seems to be working and the neuropathy has subsided. I wonder whether its possible to simply continue on this combination regime without making any more changes.
Hi isaac777, welcome to CWE. :hello:

My wife was on phenytoin (Dilantin) for many years too. It worked fairly well for most of that time too, but near the end, she started having a lot of problems. The best I can describe it is she became hyper sensitive to it. It's like the range of the therapeutic blood syrum level narrowed a lot. Too little Dilatin and she had seizures (went status epilepticus several times). Too much and she had very strong side effects - dizzyness, nausea, etc. It became clear that she had to wean off of it (Dilantin) because both ends of the spectrum were becoming increasingly more frequent and dangerous.

Her neuro tried several alternative drugs before getting her on her current regimen which has finally established a modicum of balance for her with respect to controlling the seizures with tolerable side effects.

At some point in your Dilantin weaning, you are going to have blood syrum levels less than the therapeutic range. At that point, you might as well completely wean off of it, because it isn't really doing anything for you anyway, and there are risks/consequences for long term Dilantin use.
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